1 Empowering Innovation Together Jack Johnston, Director TABLE OF Marketing Communication

Contributing Authors CONTENTS Sal Amarasinghe Andy Stanford Clark Bob Martin Michael Parks Foreword: From Idea to Prototype Akash Gujarati 3 By Sal Amarasinghe Mike Reed

Technical Contributors Inside the Proof of Concept 5 Andy Stanford Clark, IBM Chief Technology Officer for UK and Ireland, Joseph Downing IBM Master Inventor Paul Golata Nihar Kulkarni Tools for Hardware Development Christina Unarut 13 Bob Martin, Senior Engineer and Subject Matter Expert in Rapid Prototyping at Microchip Technologies Editorial Contributors

Designing, Producing, and Testing Circuit Boards Julie Emmons 23 Michael Parks, Senior Vice President of Engineering Design, Green Heather Hamilton Shoe Garage Design & Production Prototyping: Developing Embedded Software Hannah Baker 31 Akash Gujarati, Senior Embedded Software Engineer for Magic Leap With Special Thanks Kevin Hess Prototyping: The Art of Putting It All Together Sr. VP, Marketing 39 Mike Reed, Mechatronics Engineering Lead at HAX Russell Rasor VP, Supplier Marketing

Jennifer Krajcirovic Director, Creative Design

Raymond Yin Director, Technical Content

Mouser and Mouser Electronics are registered trademarks of Mouser Electronics, Inc. Other products, logos, and company names mentioned herein may be trademarks of their respective owners. Reference designs, conceptual illustrations, and other graphics included herein are for informational purposes only. Copyright © 2019 Mouser Electronics, Inc.—A TTI and Berkshire 1 Hathaway company. 2 cycle as possible. This requires a well-managed, technical and functional specifications. The answer can FOREWORD: FROM IDEA TO PROTOTYPE disciplined program of building and testing, with a clear only come from one place, and that is the customer. understanding of what questions each prototype is trying You are building the right thing if the customer accepts By Sal Amarasinghe for Mouser Electronics to answer. It also involves a broad set of tools and skills, it. That’s why it is critically important to get through from industrial designers to electrical engineers and your iterative cycles and begin testing prototypes with business modelers. As you build and test, you will be your customers as soon as possible so that you are not working toward a high-fidelity prototype or MVP that is wasting time building design features they do not want. Sal Amarasinghe is an electro-mechanical engineer who is passionate about building innovative products and a step away from becoming a product that is ready for There are both human and technical aspects of every manufacture. design, and there are many reasons why customers services by integrating design, engineering, and business. After graduating from the University of Waterloo in accept some products and reject others. At the end of Canada, he spent 5 years helping companies like Apple and Microsoft designing consumer electronics that you use The goal of the prototyping process is to answer that the day, a product will only be successful if customers every day. He joined MIT as a graduate student in product design to better understand the human-centered design really big question: Are you building the right thing? The accept it and eventually buy it. If they do that, then you answer is not found by going through a fixed number are building the right thing. process. Sal is now a co-founder at Human Element, a design consulting firm, which helps large organizations of prototypes or assuring that the prototype meets its design radical new products and services for humans using their patented Whole Human Design methodology.

Why build prototypes? When you have an idea and you physical design team may be working on a 3D model begin thinking about how to build it, the first and most while the engineering team is creating a schematic and fundamental question you must answer is this: Are you putting together boards and components to build rough building the right thing? The purpose of prototyping is to working prototypes. While they are working on their answer that question. respective aspects of the design, business developers are investigating the market and identifying potential Although it is a simple question, it may not have a simple customers who can become prototype testers. Medium- answer. That’s because the answer is made up of several fidelity prototypes may not be ready for customers yet, parts. Does it look right? Does it work the way it should? but they receive broader exposure and testing, and they Do customers like it? Finding the answers requires a are seriously addressing questions about how to build the multidiscipline approach involving design, engineering, necessary functionality and how the product should look. and business interests. More and more companies are adopting an integrated approach with product teams As the prototypes become more refined through made up of designers, engineers, and business people all feedback, designers and engineers will begin to merge working closely together. their efforts to create a looks-like/works-like high-fidelity prototype. This is a working model that is very close to Prototyping is an iterative process that begins with what the finished product will look like. It may serve as something as simple as a sketch, a computer design, or a minimum viable product (MVP), and it will be used for a physical mock up. This earliest stage is a low-fidelity more extensive testing with people who would be actual prototype, and its purpose is to begin testing the idea, to customers. begin answering those questions about whether this is something customers want. Even before this earliest stage Prototyping is a process of building, testing, and repeating of prototyping, designers, engineers, and business people until you define what the product will do, how it will look, get together, interview stakeholders, and begin to develop and how you will build it. Prototyping is also a process of an idea of what exactly this product is going to be and failure. Failing fast is important in a prototyping process. what features need to be in it. If you are an entrepreneurial When you build a prototype, you test it as quickly as engineer working on your own, you still need to be possible, and if it works, that’s great. If it fails, that’s answering those same questions. It’s those earliest even better because that means you’ve figured out very requirements that go into making a low-fidelity prototype. early on something that is not going to work. Your next iteration will have a better solution. The prototyping Based on initial feedback, prototyping moves forward process involves creating as many iterations as possible with looks-like physical designs and works-like functional within budget and time constraints, always working to designs. These are medium-fidelity prototypes. The solve the biggest challenges as early in the prototyping

3 4 Inside the Proof of Concept

By Mouser Electronics with Andy Stanford Clark, IBM Chief Technology Officer for UK and Ireland, IBM Master Inventor

5 6 INSIDE THE PROOF OF CONCEPT By Mouser Electronics with Andy Stanford Clark, IBM Chief Technology Officer for UK and Ireland, IBM Master Inventor

Professor Andy Stanford-Clark is the Chief Technology Officer for IBM in UK and Ireland. He is an IBM Distinguished Engineer and Master Inventor with more than 40 patents. Andy is based at IBM’s Hursley Park laboratories in the UK, and has has been working in the area that we now call the Internet of Things for more than 20 years. He has a BSc in Computing and Mathematics, and a PhD in Computer Science. He is a Visiting Professor at the University of Newcastle, an Honorary Professor at the University of East Anglia, an Adjunct Professor at the University of Southampton, and a Fellow of the British Computer Society.

When working through a new design, the inventor needs Sometimes the boundaries between POC and prototype to recognize where in the innovation process he or she are fuzzy. Almost as soon as you have an idea, you will is and what’s needed to move to the next stage. Most begin thinking about how to build it. And the ultimate designs begin with an idea. Next, there is a stage of idea validation of a concept is building an actual working validation that happens before moving on to the next prototype. This article is about working through the first level, which is building functional models that look and stage of engineering, which we refer to as the proof of work like the finished product. concept (POC), and getting to a point where you are ready to begin seriously building prototypes. Not everyone uses the same terminology for these stages of development. In this article and eBook, we are defining Most ideas come in the context of a problem that needs them as follows: a solution. Andy Stanford-Clark, IBM Chief Technology Officer (CTO) for UK and Ireland and IBM Master Inventor, Proof of concept (POC) – This is the first stage of idea describes it in this way. “Most of my inventions come from validation. It describes exactly what the invention will do, seeing the problem first. I see a problem out in the world, how it will work, and that it can be done. The POC uses either I come across it or a client tells me about it, and documentation and often then I sit and mull it over for a while, and some code or hardware “...the real work begin(s), and it then, ‘Bing, aha!’ I have that inspiration to prove the initial flash of in the shower.” Only after that initial rush inspiration is possible. It starts by asking basic questions of inspiration does the real work begin, must satisfy the inventor such as, ‘will this device solve the and it starts by asking basic questions that an idea is workable and problem,’ and, ‘is it technically such as, ‘will this device solve the the potential investors that problem,’ and, ‘is it technically feasible?’ it’s worth taking to the next feasible?’” stage. The real purpose of a POC Many inventors think of a POC as sketching out an idea to Prototype – This is a working model that looks and show that it is logically sound and cobbling together some functions like a finished product. The purpose of a parts or code that prove it can work (Figure 1). At some prototype is to work out the physical and engineering level, that is a POC. But a POC is not just a minimum details of how to build the invention. Prototypes answer threshold of proof or a recipe of things that make up a questions about physical and functional design. They also standard presentation. The POC is defined by what it answer questions about usability and marketability. The must accomplish. Figure 1: Not just a sketch; a proof of concept ultimate goal of prototyping is to develop an idea to the should be technically sound and marketable. point where it is ready for manufacturing and release to customers.

7 [CONT’D ON NEXT PAGE] 8 Regardless of whether you are building a better level of funding you seek and what you plan to do with the mousetrap, a control system for an autonomous vehicle, funds you raise. In some cases, the crowdfunding process or a consumer device, a POC must do three things: itself becomes part of the POC in that it validates market Figure 2: In the POC phase, you must provide interest in the idea. enough information to engineers or investors to show • It must convince you that your idea is technically feasible that the solution is sound. and it has market viability. The key elements included in a POC are:

• It must convince others of those things. Concept overview – This is an executive summary that • It must show that you have a path for reaching technical provides an overview of the problem, the invention that feasibility and market viability. will solve it, who would buy it, a summary of its unique capabilities or technology, and what you have done so far. Convincing yourself that an idea will work is often the easiest part because it’s your idea and it’s easy to gloss Problem and solution description – This provides a over some of the more subtle proof points that a potential more detailed look at the problem your innovation would customer or investor would like to see. After all, at this address. This part of the POC can include practical point, a lot of the investment comes in the form of your examples of what people do now without your invention, own time and money spent putting something together and how your solution would change that. It would talk that demonstrates a key aspect of your idea. about who exactly will be interested in this and how they would use it. There should be a discussion of market size But at the end of the day, a POC is a document or and the business model you have in mind for tapping that presentation designed to sell the idea. It is used to market. If you’re envisioning a new kind of rugged, all- convince others, to win POC funding needed to build weather electric bicycle, you have to consider whether or and test real prototypes, and to attract additional capital. not you’d sell to consumers through traditional retailer. Is Funding may come from research grants, investors, it something you would sell to municipalities that want to accelerators, or business partners, all of whom are implement a pay-per-use public service? Is it something looking for the greatest return with the least risk to their you plan to sell to bike rental businesses or resorts? The investment. problem and solution discussion describe the what, who, and how of your concept in enough detail that people can What’s inside a POC? clearly see what you have in mind. Exactly what you include in a POC depends on the Technical description – This part of the POC goes product and the potential investors. “It varies,” explains into greater technical detail about the solution itself, Stanford-Clark, “and it’s often based on how much providing a level of detail that is appropriate and technical detail they need.” necessary to achieve the audience objective. This could include conceptual diagrams, physical and operational In B2B projects, you may be working closely with an details, overall system architecture, schematics, and engineering team of potential customers or investors. discussions of components that will go into your They will understand the problem and the solution you invention, with a focus on the unique technical aspects are working toward. Showing them key concepts and that set your solution apart from other products. More technologies you plan to use may be all that’s needed to detailed technical information might include power move them to the next level. The next level might be a source, sensor types, processors, connectors, interfaces, contract of finite length that specifies a working prototype communications, security architecture, and other aspects that will be built to deliver certain functionality, measure of the design. results, and perform a cost-benefit analysis.

You can provide this information through documentation, In a consumer product, potential investors may want specifications, and even a physical mock-up or demo to see a more formal presentation that talks about the (Figure 2). The goal is to provide as much information as technology, walks them through a demo, discusses the is necessary to convince an engineer or funding entity that business model, provides market analysis, and tells them the solution is sound, but you don’t want to give away so what resources you need for further development. In a much that someone can steal the idea. crowdfunding scenario, the POC may be a description and a mock-up of the product, again depending on what

9 [CONT’D ON PAGE 11] [CONT’D ON PAGE 13] 10 One approach to the technical description is to do it as all the outstanding issues you intend to resolve through a first ‘Hello world’ message across the Atlantic and halfway the next level of development, which is a more refined if you were filing a patent. “If you’re filing a patent to prototyping program. These can be technical and physical across America six thousand miles away. It was magical!” prototype, which becomes the POC for the next level of get intellectual property protection for an invention, you design issues, usability issues, component selection A lot of work goes into proving a concept, and sometimes development, until you have a manufacturable product. need to write it up in a format that teaches somebody and costing, and market readiness questions. Your plan the boundaries between POC and prototype are not clear. And even then, the work does not end. knowledgeable in that technology area how to do this will also need to discuss a timeline for your prototyping The best dividing line may be when you move from POC new thing you’ve invented,” explains Stanford-Clark. program, what physical resources you will need for to prototyping, you are moving from experimentation to The next articles talk about different aspects of Doing it this way will provide a good technical description, fabrication, assembly, and testing, and how much money earnest development with a product as the end goal. prototyping, including commonly used development tools, although you may choose to leave some of that detail out you need to accomplish your goals. These boundaries become fuzzy because everything circuit board design, embedded software development, of the POC. you do is done to move you to the next level. In a sense, and how to put together a prototyping program. The POC is flexible in that it should adjust to the every working prototype you build becomes the POC for Business plan and cost justification – This section of audience. Its purpose is to convince people, especially the POC provides more detail about your business model, potential investors, that investing in your idea is a risk your estimate of acceptable market pricing and product worth taking. It also serves as a reality check. If the POC production costs, and how you arrived at those estimates. fails to reinforce your own belief and passion in your idea, For example, you may have unique market knowledge, then you will have a hard time selling it to others. or you may have market research that helps answer business questions. You may have already done a round From POC to Prototyping of crowdfunding and from that, you are able to make As you work past your initial inspiration to figure out if informed statements about how the market would receive your idea is possible, you are probably building something your solution. to prove to yourself that it can be done. You’re putting things together to see what works. This is the beginning It’s important to include a cost-benefit discussion. Most of the POC, and in many ways, it’s the most exciting inventions, even those that represent an entirely new kind part of innovation. You work late of product, are competing at night, and maybe you work with with other products or old “It’s important to include a cost- somebody who takes a few days to ways of doing things. Maybe benefit discussion... you need to do their part before getting back to your invention automates you to test something. something that is done show that the benefit of your solution manually. There is a benefit outweighs the cost.” Stanford-Clark, who is also an to that. You need to show inventor of the Message Queuing that the benefit of your solution outweighs the cost. A Telemetry Transport (MQTT) messaging protocol, very simple example is a device that delivers the same described the experience like this: “It was like Marconi functionality as popular brands but at a third of the cost. sending the first message to America. I was in the Isle of Wight in the UK, and my co-designer of MQTT was ® ® ® ™ Development plan – This explains where you are in your Intel Cyclone Intel RealSense sitting in Kansas City, and we’d both written some code current development, and what you need to turn your idea on a Friday afternoon. We were on the phone with our 10 GX Development Kit Tracking Camera T265 into a market-ready product. For many innovations, this headsets, both typing away. Things came through, but it requires laying out a prototype testing plan that details was garbage. We went back and forth until we sent that mouser.com/intel-cyclone-10-gx-kit mouser.com/intel-realsense-camera-t265 11 12 Tools for Hardware Development

By Mouser Electronics with Bob Martin, Senior Engineer and Subject Matter Expert in Rapid Prototyping at Microchip Technology

13 14 often programs and arrangements When you begin building early-stage In addition to parts for building TOOLS FOR HARDWARE DEVELOPMENT available that give qualified people prototypes, you will start collecting prototypes, you need equipment to access even if they are not directly parts. You may use a generic test them (Figure 2). By Mouser Electronics with Bob Martin, Senior Engineer and Subject Matter Expert in Rapid Prototyping involved with the university. Bob evaluation board, and in scrounging at Microchip Technology Martin, Senior Engineer and Subject for components, you will discover Hardware Test Equipment Matter Expert in Rapid Prototyping that certain parts are popular. In Every well-equipped lab will need at Microchip Technologies, notes working out key aspects of a design, these basic pieces of test equipment: that these facilities often come with you might purchase breakout A maker before it was a term, Bob Martin has been tearing apart things to see how they work all his life. He has a built-in community of engineers boards from vendors to quickly test • Digital Multimeter (DMM) – used and enthusiasts who like to share concepts and do rapid prototyping done everything from installing specialized instruments at arctic weather stations to support atmospheric research to measure voltage, current, and ideas. “It’s amazing how much in a process that’s like building with resistance. In selecting a DMM, campaigns. Now, he serves as the “Wizard of Make” for Microchip Technology, where he keeps the maker spirit people at colleges love to talk about electronic Legos. consider resolution (more display alive within Microchip Technology, educates aspiring makers, and continues to create, experiment and explore. He engineering projects,” he says. digits typically indicate higher Colleges can be a great place to find Eventually, you will need to take that lives in Sunnyvale, California, with his wife, twin daughters, a cat with no teeth, and a garage full of surplus wire and resolution), accuracy, auto-ranging, support when you are in your earliest early-stage prototype consisting of “vintage electronics” that really should be recycled. and true RMS capabilities. stages. breakout boards, wires, sensors, and other components all plugged • Oscilloscope – used for testing Eventually, many engineers want to into a breadboard and start refining analog sections of a circuit, this build out their own lab space. The the design with actual parts and is an essential tool for analyzing Turning an idea into a working need some basic tools to develop is not an option and you do not have basic ingredients of a good bench prototype requires a place to work their hardware project. This article access or a well-stocked corporate are plenty of workspace, good and tools that will get the job done. provides a high-level overview of the facility, there are many well-equipped Figure 2: Components plugged into a breadboard in the early lighting, and a good bench power Corporate engineers or those who resources you will need to build and fab labs and makerspaces available stages of prototyping. supply. The type of power supply have hardware accelerator support test prototypes. for use at a reasonable cost you need depends on the type of will have access to equipment and (Figure 1). These can be great places work you are doing. A good bench hardware. Entrepreneurial engineers to start. Lab Facilities supply allows you to adjust voltage and makers must either build Every engineer needs a lab of some outputs and dial in very accurate their own lab or find access to the Many of these facilities are kind. Many begin with a workbench voltages. There are many choices equipment they need. Regardless associated with university in their basement or garage. If that in bench supplies, including output of who you are, every engineer will engineering programs, but there are ranges, number of channels, current limitation controls to protect delicate Figure 1: The image shows an example of an engineer’s workbench. components, and linear vs. switching power supplies.

In addition to these basics, you will need components and test equipment.

Parts and Components components. That’s when you see waveforms, troubleshooting circuits, the real benefit of working in a lab One of the benefits of working in and evaluating signal quality. When with a large collection of parts. an established lab is that they often choosing an oscilloscope, consider “Those part collections are like tribal have part collections useful for bandwidth, which specifies knowledge. They’re the canon of prototyping. These may be parts they frequency ranges it can measure, popular parts that lab managers keep in stock because they are used sample rate, the number of collect because they trust those a lot, surplus parts from previous channels it can measure, its ability parts. You’re getting that tribal projects, or parts donated to the to store waveforms and the record knowledge, and with that comes the lab by organizations. Some fab labs lengths it can store, triggering schematic symbols and footprints maintain very large collections of capabilities, and the types and whatever CAD package you’re parts and components. configurations of probes that are using,” Martin explains. compatible with the scope.

15 [CONT’D ON PAGE 18] 16 • USB Logic Analyzer – used to display and test digital signals. “The USB logic analyzer is the real star of the show, especially if you’re working with microcontrollers,” Martin says. Key features to consider include the number of channels it can track, how much continuous signal measurement it can store, and sample rate. Some logic analyzers have their own displays, and some are designed to plug into a computer and run with proprietary software. provide integrated end-to-end design functionality that starts with In addition to test equipment, you schematics and carries through will need electronic computer-aided directly to the PCB layout portion design (ECAD) to create schematics of the program. This is an essential and PCB layouts. capability.

Electronic CAD • Intuitive interface. One of the most important selection criteria ECAD and Electronic Design is whether you are comfortable Automation (EDA), provide essential using the application. Martin functionality for designing electrical explains, “These applications all circuits, creating schematics, creating have different user paradigms in printed circuit board (PCB) layouts, how they organize their interfaces. and generating all documentation One of these user interfaces is needed to fabricate PCBs and build going to click with you and be PCB assemblies. Although high- much more intuitive than others. end ECAD solutions can be very That’s the one you want.” Martin expensive, there are good free and advises downloading trial versions trial versions that provide sufficient and working with them to find one functionality for many projects. Also, you like. This does not need to be using trial versions is a great way to an endless research project. You check them out before investing in a can usually tell pretty quickly if the premium version. application makes sense to you. He also suggests looking for packages ECAD applications use standard that have good video tutorial symbols for building schematics, support. “All the good packages, and they offer comparable features free or not, have excellent video commonly used in electronic design. tutorials,” he says. “If it’s sparse on However, there are certain things to video tutorials, you probably want look for when deciding on the right to look elsewhere.” ECAD package. These include: • Flat and hierarchical schematics. • Complete functionality. It used to Many projects work fine with flat be that schematics were created schematics, but more complex in one ECAD application and PCB designs benefit from hierarchical layouts in a separate program. schematics that allow you to Now most ECAD applications collapse sections of the diagram

17 [CONT’D ON NEXT PAGE] 18 while still seeing all the connections the exact parts you intend to use dimensions, hole sizes, number of that go into that section. Martin in your prototype. Martin notes, layers, and other essential design says, “If your design is only a few “You can go to the web site of your features. There may be special pages long, flat schematics work favorite parts vendor and get CAD constraints for certain parts of the fine. At some point, hierarchical symbol downloads for actual parts. layout such as the power section becomes more manageable. You It’s really convenient because, not or RF section. Being able to specify can grow into it. You might start only do you get the symbol, but you these design constraints in detail with a flat schematic, and if your also get the actual footprint.” is fundamental to creating a board design is getting to six or seven layout that will work and that can be pages, you probably want to start • Back annotation. Back annotation fabricated. looking at hierarchical.” A good allows you to make a change design package will allow you to go at the PCB layout stage which • Trace length matching. This is either way. automatically updates netlists and a very important aspect of PCB the schematic. For example, you layout, especially in designs that • Text searchable PDFs. This is the may discover during layout that involve high-speed signals where ability to generate an interactive routing would be a lot easier if you uneven trace lengths can cause PDF version of a schematic. Martin switched some pins around, which variations in how long it takes says, “Text searchable PDFs are you can easily do. This changes signals to move through the traces. very useful if you are sharing a the PCB netlist, but with back PCB layout functionality should design with someone who does annotation, it will also change the support trace length matching. not have your ECAD package.” schematic netlist. Searchable PDFs break out the • Auto-routing – proceed with net names so that if you click on a Creating a schematic is just the caution. Many ECAD applications net name on one page of the PDF beginning of the design process. support auto-routing, and some schematic, it will automatically Once you have a good schematic, work better than others. It’s highlight the netlist across all the you will need to turn it into a PCB important that the auto-routing pages in that schematic. You can layout for fabrication. be fully controllable by design also search for specific part names constraints. Auto-routing is not a and instantly find the part with all its “Creating a schematic is function you would use to layout an connections highlighted. Being able just the beginning of the entire board. It should only be used in certain cases, for instance in to generate text searchable PDF design process. “ schematics is a valuable capability highly repetitive non-critical sections in an ECAD package. of a layout. It can also be helpful in PCB Layout areas of a layout where trace length • Import part-specific schematic Most ECAD packages have PCB matching is important. Martin says, information. Most ECAD packages layout functionality integrated into “Most applications do trace length have standard symbol libraries, but the application. Here are some key matching automatically, and that is you also want to be able to import features you want to consider when more important than auto-routing.” schematic information specific to evaluating ECAD packages: • Documentation. This is a standard Figure 3: Circuit simulation can be useful in the early design stages. but essential function of the • Seamless integration and ECAD application. This includes design constraints. These are maintaining and outputting all the • 3D step modeling. Many ECAD files to the mechanical CAD people Simulation basic capabilities that are almost packages provide 3D STEP models, who can use it for enclosure design. documentation for fabrication and A circuit simulator uses schematic default requirements in any ECAD which allow you to display PCBs assembly, including bill of materials and mathematical models to package. Seamless integration is in 3D. This is a highly valuable In addition to creating schematics, (BOMs), assembly plots for board simulate analog circuit operation complete functional integration capability that accelerates PCB layouts, and documentation, layers, and drill tables. Part of the for analysis. Without building an between schematic design and packaging design by providing there is one other important function documentation includes Gerber operational prototype, you can use PCB layout. You should be able you with a complete 3D profile so provided by design software. That is or ODB++ output files, which are circuit simulation to look at signal to work on either and have those you can see how everything will fit circuit simulation. used by the PCB manufacturer to propagation in a circuit, power levels, results reflected in the other. together. 3D STEP models allow fabricate your boards. and thermal dissipation. This is Design constraints are design rules you to visualize your assembled useful in early design stages to verify such as board dimensions, trace board, and you can send 3D STEP

19 [CONT’D ON NEXT PAGE] 20 a design and help in component is a very expensive, specialized Mechanical CAD model into the mechanical CAD selection (Figure 3 on previous service. That, and the cost of application is a key capability. CONSIDERATIONS FOR COMPONENT Many mechanical CAD applications page). getting Federal Communications provide 3D modeling functions Commission (FCC), certification for a capable of creating enclosures and AND SOFTWARE SELECTION Simulation functionality is wireless design is one reason many Working with Digital supporting 3D printing. From the increasingly becoming a feature of engineers use pre-certified modules Components electrical engineer’s perspective, ECAD applications, either through in their RF designs. In addition to the ECAD tools By John Teel a key mechanical CAD capability linking to Simulation Program with and test equipment discussed is being able to import a 3D step Integrated Circuit Emphasis (SPICE), so far, many designs require “Changing a component later in the development process model of the PCB board that is a widely used open-source circuit “...a key mechanical CAD digital components such as generated by your ECAD application. can add considerable time, cost, and quality issues, so it’s simulator, or as an integrated part capability is being able to microcontrollers and field- This enables you to quickly see best to get it right from the start.” of the ECAD application. It can be programmable gate arrays import a 3D step model how the assembled board fits into very helpful in designing analog (FPGAs) that need their of the PCB board that is the enclosure and where all the circuits, but it is less useful for digital own development tools and Choosing components touchpoints will be. “PCB board components such as those involving generated by your ECAD strategies. Many development designers work with mechanical Freelance engineers and startups often design the product first with a focus microcontrollers. application. “ tools used to program these packaging guys,” explains Martin. on performance, analyzing the cost impacts of the selected components parts, such as the integrated “They’ll generate that 3D STEP afterward. Instead, engineers should take a closer look at component costs For designs involving radio When you have designed, built, and development environment (IDE) for model and hand it off to the and their impact on the overall cost. Also ensure that the component will transmission or wireless connectivity, tested your PCB assembly, you will microcontrollers, will be specific mechanical CAD guys who will pull continue to be available in high quantity for the life of your product. RF simulation is essential in antenna need to put it into an enclosure. For to the part or part family you are it into the enclosure, rotate it, and The component package can add to the cost. For example, a leadless design and evaluating the circuit for that, you will need mechanical CAD. using. In the case of FPGAs, you take dimensions from it if necessary.” package like QFN will add costs compared to a leaded package like an regulatory compliance. RF simulation will likely be using a hardware Being able to put that 3D STEP SOIC. When selecting components that will dissipate considerable power, description language such as take that into account. Verilog or VHDL. In both cases, you will need logic simulators When selecting components, visit a distributor’s website, like Mouser.com, designed for digital circuits that instead of individual manufacturer websites. Comparing components from allow you to incrementally step multiple manufacturers on one site makes the process much more efficient. through code one instruction at a Finally, consider the manufacturer’s support level. Some component time and measure how each line of manufacturers will offer more support to startups than others. code affects signals in the circuit.

You will also use testing strategies, Selecting hardware development tools such as function partitioning, Developing custom electronics starts with a schematic circuit diagram that which allow you to isolate just one is high-level and conceptual. Then the schematic diagram must be turned portion of the digital circuit to test into a real-world Printed Circuit Board (PCB) layout. These steps are done its functions independent of what in the same software, which checks to ensure the PCB layout matches the is happening in the rest of the schematic diagram. Two of the most popular software packages are Altium circuit. This becomes necessary and Eagle. When designing your own product, consider a low cost software in complex circuits in which a called DipTrace. All of these packages output PCB design files called microcontroller may be performing Gerber files which can then be sent to a PCB manufacturer for prototypes one kind of process while an or production. Be sure to design your PCB layout with debugging in mind, FPGA is performing a different but which generally means adding plenty of testpoints. dependent process. For debugging electronics, you need a well-equipped lab area with With a fully equipped lab and tools such as power supplies, voltage meters, oscilloscopes, function design tools, you will be able Microchip Technology dsPIC33CK Microchip Technology SAM R34 generators, and other equipment. Most modern electronic products include to move to a critical stage in a programmable processor such as a microprocessor or a microcontroller, Curiosity Development BoardApplications Xplained Pro Evaluation Kit prototype development: Circuit so debug work will also be done inside the Integrated Development design, which is covered in the Environment (IDE) software. next article. mouser.com/microchip-dspic33ck-board mouser.com/microchip-sam-r34-xpro-eval-kit

21 22 Designing, Producing, & Testing PCBs

By Mouser Electronics with Michael Parks, Senior Vice President of Engineering Design, Green Shoe Garage 23 24 DESIGNING, PRODUCING, AND TESTING PCBS

By Mouser Electronics with Michael Parks, Senior Vice President of Engineering Design, Green Shoe Garage

Michael Parks, P.E. is the owner of Green Shoe Garage, a custom electronics design studio located in Southern Maryland. He blogs and occasionally podcasts at Gears of Resistance, a site dedicated to raising public awareness of technical and scientific matters. Michael is also a licensed Professional Engineer in the state of Maryland and holds a Master’s degree in systems engineering from Johns Hopkins University. Most importantly he gets to be a dad to his daughter Hailey.

Making Printed Circuit Boards Schematics and PCB board designs are not the same thing. Schematic diagrams show how the circuit An essential part of building a prototype is creating a functionally works to meet device specifications, printed circuit board (PCB), assembling components whereas a board design shows how all the components onto the board, and testing the assembly to make sure are physically connected. Michael Parks, Senior Vice everything works the way it is supposed to. To do this, an President of Engineering Design at Green Shoe Garage, “Schematics are crucial to engineering team must design the circuit, create a board describes it in this way: “Schematics let the designer layout, and either fabricate the board or send it out for move a circuit idea from the brain to a digital file that fabrication (Figure 1). can be shared, edited, and saved for future iterations. understanding how a circuit will Schematics are crucial to understanding how a circuit will work functionally.” Figure 1: Engineers designing, creating and fabricating work functionally.” prototype boards. Schematics allow you to answer questions like, ‘Does my microcontroller have enough pins to handle all the sensors I want for my design?’, and from a collaboration perspective, they make conveying the design to other engineers easy through the use of standard symbols to delineate different electronic components. A schematic also shows the interconnection between components in a very easy to comprehend manner. Good PCB layouts are based on good schematics, so that is where the work begins.

Designing a Circuit and Creating the Schematic A circuit design always starts with a specification that describes in detail what the device will do. From that Many services now offer low-cost custom board specification, the engineering team will create a block fabrication with quick turnaround. The real challenge diagram showing the relationship between various is creating a good PCB board design. Although some functions needed to fulfill operational requirements. Based engineers will jump directly into designing a PCB layout, on that block diagram, engineers will select specific this is never a good idea. It creates less than optimum components needed to perform those functions. designs, and in the case of a complex project, the results can be disastrous. The better approach is to develop a Engineers typically use an electronic design automation schematic first. (EDA) tool to do this design work. EDA software has Figure 2: A flat schematic example

25 [CONT’D ON NEXT PAGE] 26 all the functionality needed to create designs, perform else’s circuitry, but you only really care about the inputs • 0.010” trace widths will do for most low power digital and circuit simulations and analysis, create PCB layouts, and and outputs of their part and not necessarily how the analog signal traces. 0.030” traces for 1A and 0.100” for generate files that PCB fabricators use to manufacture internal components are wired. In that case, a hierarchical 4A. Also, keep at least 0.010” between traces and pads. boards. Creating a schematic is an iterative process that schematic can render their part as a black box you will moves from block diagram to a drawing that shows more be incorporating into your design, but it also allows you Best practices when designing RF or detailed component relationships, and ultimately to a to look at that black box circuitry in the future if you need microwave PCBs detailed schematic showing pin connections based on to better understand its inner workings. It also makes • The ideal trace length for an antenna is 1/4 wavelength. actual component specifications. updating the design much simpler should parts become That provides a good balance between RF performance obsolete in the future. Or if the developer wishes to offer a and board size. When creating schematics, engineers have a choice family of products with slight variations. For example, an of either using flat or hierarchical schematics. A flat environmental monitoring platform that offers both a Wi-Fi • Never use 90° turns in traces carrying microwave (multiple GHz or more) signals. “Using two 45° turns schematic is one in which the entire design is detailed radio option and an LTE radio option. General PCB design best practices on a single sheet or multiple interconnecting sheets is the least noisy geometry for gigahertz signals,” says for large and complex designs (Figure 2 on previous Once you have a completed and verified schematic, it is • Place components that require a specific location on Parks. “This prevents noise from reflections as signals page). A hierarchical schematic shows a design made time to create the PCB layout. the board first. These include parts such as USB ports, race around the PCB.” up of functional blocks with pin connections between the connectors, buttons, and switches. • Place copper pads along the signal trace to allow for blocks. Clicking on a functional block provides expanded Creating a PCB Layout • Try to place all components on the same layer of the points to connect surface mount inductors and/or schematic detail for that section. Some engineers prefer EDA software typically contains functionality that helps board. capacitors for fine-tuning the circuit. Parks explains, traditional flat schematics, but hierarchical schematics you turn a schematic into a PCB layout. This includes “This is important because material properties in have their advantages. • Minimize the lengths of traces by thinking about which the ability to set basic design rules, such as PCB size, the components and traces can vary from one PCB parts will be physically interconnected and placing them trace widths, hole sizes, and other design rules that help assembly to the next. This allows you to build a ‘close Parks notes that “If you are working on a design where as close as possible to each other. ensure you do not create a layout that is impossible to enough’ board and then fine-tune during testing.” multiple people are contributing, a hierarchical schematic manufacture. Even when using modern EDA software, • Align polarized components the same way. For example, makes it easier to work asynchronously. It allows you The ground plane should always be continuous under there is an art to creating PCB layouts. Though it is always have positive leads face to the right on the PCB to abstract away the complexity of parts that you are RF components and transmission line traces. Include a beyond the scope of this article, the following are helpful and use a square pad for positive terminals. going to treat as ‘plug-and-play’.” For example, let’s say generous amount of ground vias between layers around best practices: you are building a PCB that will incorporate someone [CONT’D ON NEXT PAGE]

TWO BIG PCB DESIGN PROBLEMS Inadequate PCB testing

By Josh Lifton No matter how careful you are, PCB production can • Exclave is a tool that makes factory testing of boards create faults, errors, and defects. Testing at all phases much easier. Several Crowd Supply projects have of design is crucial. Here are some resources that used Exclave. Part Obsolescence can help you develop testing techniques for your PCB design process: There are many PCB design problems, but one of • Information on parts availability and status is the biggest and most pervasive is designing around constantly changing. Manufacturers do notify their • Circuit Talk ezine published by Screaming Circuits obsolete or hard-to-get parts. If manufacturing will customers of parts that are nearing the end of their is a publication written by experts from an assembly happen months after the design, the chances of parts life, so staying abreast of these notices is vital. house perspective, with articles that explain common being unavailable greatly increases. • When a part is likely to be in short supply or obsolete, pitfalls and how to avoid them.

seek out information on the source and availability of There are several ways to mitigate this risk: • InspectAR is an up-and-coming tool that is currently replacement components. Locate online databases in beta. It uses your phone to overlay metadata (e.g., • Shorten the amount of time between PCB design and where you can quickly search for hard-to-find schematics, electrical nets, and part datasheets) manufacture. components. onto the board you’re holding. InspectAR has a lot of • Confirm the availability of parts with vendors and potential to make the testing and debugging workflow determine which parts may be at risk. much more efficient.

27 28 the RF portion of the PCB. “This helps cut down on as capacitance tests that look for shorts, and resistance and developing a test plan are all crucial before • Not keeping the parts list updated after changing cross-coupling between the low-speed signal lines and tests that verify proper current flow through the traces committing to larger production runs. components in the board design, and subsequently the RF transmission lines,” says Parks. “In other words, (Figure 3). spending lots of money on the wrong parts. it reduces noise being induced on the low-speed signal Parks as a big fan of getting boards and prototypes made lines (acting as a receiver) from the high-speed RF lines PCBs that pass these tests will need to be populated with as quickly as possible so that problems can be found and Next Steps (acting as a transmitter).” components. That completes the electronic portion of the corrected early in the process. “People are often afraid to Part of the PCB design process includes creating prototype. Note that a bare PCB is just the board without take that first step,” he says. “PCBs have become cheap. PCB fabrication drawings, Bill of Materials (BOM), and A Word About Auto-Routing any components. Once components are soldered onto I encourage getting their boards made and out there, and assembly drawings, and keeping these documents up the board, it becomes a printed circuit board assembly if nothing else, it’s the failures that will teach you most.” Most EDA software has auto-routing functionality that to date with the most current prototype iteration. EDA (PCBA) or simply a printed circuit assembly (PCA). Parks speaks from experience. Some of the common and will layout the PCB based on placed components and software is able to generate all this documentation along painful mistakes he has endured include the following: schematic information. Most engineers do not use auto- with electronic files needed for fabrication and assembly. It’s important to recognize that PCB layout is often more routing except in particular circumstances. For instance, art than science, especially if you are dealing with RF • Polarized components getting placed backward. auto-routing can save time when laying out a highly Once you have a working PCA, it will go to the embedded or high-speed signals. Trace lengths and topology can repetitive, non-critical area of a board, such as an LED software engineer who has been working on the code that be culprits in whether or not a board works. Also, the • Overheating due to making traces too thin. display, or when trying to locate a difficult connection will drive your device. It’s time to load and run software manufacturing process is not perfect. Sometimes a between two specific pins. However, using auto-routing • Crosstalk from traces being placed too closely together. on the actual prototype hardware and test the design’s perfect design can be foiled by a pick-and-place machine to lay out critical areas or an entire board will result in an While not very common, it was the hardest to diagnose. operational capabilities. Creating embedded software is placing a surface mount diode on the board backward. unusable mess. “Auto-routers don’t always make the best the focus of the next article. That’s why having limited test runs, building a test jig, • Not thinking about thermal management and placing choices,” says Parks. power-thirsty components too close to each other.

Other factors also influence PCB layout. For instance, Figure 3: An engineer testing PCBs. it is becoming increasingly common to use multi-layer PC boards. Parks notes several advantages. “Although putting components on one layer is ideal, a multi-layer board allows you to reduce length and width when real estate is limited. You can also put different voltage components on different layers, and use layers to block cross-talk in a circuit.” However multi-layer boards tend to be more expensive, and they can create design issues. For instance, passing a trace between layers may be convenient, but it can also add latency to a circuit.

Another PCB option is the flexible printed circuit (FPC). These are smaller, lighter, and more mechanically flexible than rigid PCBs. They are often used in wearable devices where human comfort is a design factor. Parks notes that “Certain types of additive FPC manufacturing can be very cost-effective and environmentally friendly as they tend not to require etching chemicals found in more traditional PCB manufacturing.”

Once you have a final PCB layout, the EDA software will generate design files that PCB fabricators can use to create the PCB. For prototyping purposes, you want to select manufacturers who can create PCBs in small batches at a reasonable price, and they can do it quickly.

Testing Your Circuit Board Bare PCBs should be inspected and tested before assembly. These tests include visual inspection as well

29 30 Prototyping:

Developing

Embedded

Software

By Mouser Electronics with Akash Gujarati, Senior Embedded Software Engineer for Magic Leap

31 32 PROTOTYPING: DEVELOPING EMBEDDED SOFTWARE

By Mouser Electronics with Akash Gujarati, Senior Embedded Software Engineer for Magic Leap

Akash Gujarati is a software engineer at Magic Leap where he is engaged in building the present and the future, of spatial computing. He previously worked at Tesla where he helped create the first Powerwall and Powerpack energy storage products. Throughout his career, Akash has had the opportunity to work on complex, resource-critical systems and he is glad to be involved in technology that drives the innovations shaping the future of our society.

Embedded Software Development the logic that delivers application In embedded systems development, Is Different than Application functionality. Embedded software electrical and hardware engineers Development is different in that every statement work closely with embedded of embedded code directly affects software developers to build a Prototyping involves not only hardware. It is manipulating the solution. Electrical engineers and designing and assembling a device’s hardware at a granular level so that embedded software developers work hardware, but also developing the device functions the way it is together to understand component the embedded software that supposed to. Embedded software details, schematics, and basic makes the hardware components developers need to understand the electrical engineering principles, function. Embedded software capabilities of hardware components though their roles are distinct. typically consists of device drivers, and how they must function for an operating system, and system the device to operate properly, A typical embedded software software. Device drivers directly which requires the ability to read a development process goes like this: interact with and manage hardware schematic, understand component functions. Today, many electronic documentation and specifications, • Design collaboration. The devices, such as health monitoring and use electronic test equipment, hardware and electrical engineers equipment, cars, consumer devices, such as scopes and multimeters. As begin choosing components and industrial control systems, embedded systems acquire more needed to build the system. “That’s depend on embedded software to edge computing capabilities and the when the embedded software perform essential operations. processors used in them become developer comes in,” says Akash more powerful, there may be a Gujarati, Senior Embedded Developing embedded software is growing role for app developers in Software Engineer for Magic Leap, different than creating application embedded system design. However, “to make sure they are choosing the right microcontroller or digital signal “Embedded software is different in that every processor, and to begin right away seeing what embedded functions statement of embedded code directly affects they need to support the overlying hardware.” application layer.”

there will always be a need for • Component and design review. software. Most applications embedded software developers After reviewing component choices manipulate data—they store it, who use machine code to directly with the hardware engineers, the move it, display it, and perform manipulate hardware components. embedded software developer calculations on it. Applications are reviews schematics with the entire abstracted from the underlying A Typical Embedded Software embedded team, including the hardware team, to make sure hardware. The primary focus of an Development Process application developer is to create all the signals and connections

33 [CONT’D ON PAGE 35] 34 are understood. Sometimes this developer then builds a test unit or where the initial development design concept for the product. provide greater flexibility for system great if you can spend a little more RECOMMENDEDrequires rethinking certain aspects EMBEDDED hardware emulator that will simulate happens. It is where you can see That is the last stage of developing upgrades. on a higher clock-speed controller of the design because, for example, signals the hardware is expected to that everything works, see power embedded software for the initial with more memory,” he says. SOFTWAREthey may find certain PROGRAMMING outputs on the generate. That allows for rapid code levels and waveforms, and have a product. Once you’ve reached For many years the traditional selected components don’t work as iteration and development. “It’s functional code set. Doing this with that stage and it works, you will embedded software development Integrated Development LANGUAGESoriginally planned. basically modeling the hardware so an emulator is especially important continue touching things up to language was Assembly, which Environment (IDE) you can create the signal and feed it in high power applications make it run better. compiles as machine language. Most microcontrollers come with • Hardware emulation. The back into the code,” Gujarati says. where mistakes risk burning out Today, most embedded software some kind of IDE, and there are a By Alex Elium This is components. Developing embedded software developers use another programming number of 3rd party IDEs as well. involves a lot of debugging and language, C, because it is more Eclipse is a widely used open- • Test the board. When the testing as you go. That is why it is intuitive and easier to maintain. “Right now, I highly recommend C++, although the source IDE that supports a lot of assembled board is available, necessary to iterate frequently and Both C and Assembly make it hardware. Some manufacturers build embedded world is rapidly changing, and in a few years, embedded engineers start testing see exactly how the code is driving easy to directly control underlying their IDE on top of Eclipse. Gujarati we’ll be using some kind of virtual machine or managed basic functionality to see if it can be the hardware. hardware. Many microcontroller notes that you don’t have to use the powered up, if it talks to peripherals, manufacturers provide their own environment like Java or Python.” manufacturer’s IDE. “Regardless if correct voltages are happening Operating Systems and versions of C that also include some of whether their IDE is used or not, in control converters, and testing Programming Languages Assembly instructions for critical C++ is a good choice of programming language for embedded software. switched inputs to be sure that the you have to load certain drivers and Many embedded systems require functions. C++ is also used by some In the past, C was the more popular choice as there might not have been switching is happening as expected. certain configuration files that allow an operating system (OS) that works embedded engineers, but it is not enough on-chip RAM/Flash for C++. This is no longer the case. Unless Gujarati notes that at this point, the IDE to support that hardware,” as a mediator between hardware always the right choice. Although it you’re developing an extremely high-volume application, the difference in “You’re doing a lot of development, he says. You may also have to make drivers and an overlying application has all the advantages of an object- COGS between 200K of RAM and 20K of RAM is hardly noticeable and you’re looking at things on a scope, customized drivers. logic. This can be as minimal as a oriented programming language, its the savings in development time will more than pay the COGS difference. and you’re testing out all the major very small OS that acts as a task- code often takes up more room and features, including drivers and Essential Embedded switching kernel. Most OSs used may run slower. Gujarati points out Some caveats if you do use C++: microcontroller systems, to make Development Tools in microcontrollers are real time that for some embedded solutions • Don’t use RTTI or Exceptions sure you can communicate to operating systems (RTOS), which that are less time-critical, such as The most important tool for everything that you need to talk to.” • Use the STL, but be smart about it. String, vector, map, queue, and a means they can process an input applications that monitor things, embedded software development is a micro debugger that few other containers are worth the RAM hit. And a good embedded • Build good drivers. It’s important in less time than will elapse until C++ may be a good option. “C++ is compiler will mitigate footprint impact using an optimized library. For to take the time to write good the next input. This is an essential instance, “short string optimization” can make the memory footprint of drivers so that everything running capability for devices that control std::string equivalent to a C string. Avoid more advanced libraries like on top of the embedded system real world things in real time. regex, which are probably overkill. You’ll be paying in Flash for features is easily modifiable. Gujarati you aren’t using. sights an example of writing a RTOSs come in many sizes and charging driver. “I may have to flavors. Some are proprietary and Keep in mind that the embedded world is rapidly changing, especially add an accessory that needs to be others are open source. Some with big industry players taking an interest in IoT. Eventually we’ll be charged,” he says. “I should be able microcontroller manufacturers using some kind of virtual machine or managed environment like Java or to place this directly into that new provide an RTOS with their product, Python. It’s worth taking a look at MicroEJ, an embedded Java IDE and device. If I have done my job well while others specify a number VM, and MicroPython. They are beginning to see some industry interest, as an embedded engineer, I just of different ones that will work. but at this time they are at a startup or hobbyist level of support. code how the charging happens. Choosing an RTOS depends Everything else underneath related in part on the microcontroller “It’s important to keeping an embedded software to specific outputs and controls will (smaller processors have less room development process in sync with evolving hardware be the same. Good drivers are the for software) and partly on the prototypes.” foundation.” complexity of tasks being performed. When selecting a processor, you • Implement Logic. The embedded must consider how much memory No matter what language you use, the key is automated testing and software developer builds the will be needed to run drivers, some sort of processor neutral Real Time Operating System (RTOS) logic that makes the device do the RTOS, and application such as mBed, FreeRTOS, or Zephyr. The RTOS will let you change what it must do. This is based logic. Gujarati notes that many processors without too much pain. Automated tests, like unit or system on requirements provided by the embedded engineers prefer will let you quickly verify your code base versus a new prototype. hardware team and the high-level open-source RTOSs because they

35 36 beginning that keeps hardware and Next Steps software engineers working together. Once you’ve loaded the embedded Gujarati notes that this is not always software on the prototype hardware, done well even in large companies, you are ready and it can be a to move to the real risk factor “...for the project to be a last phase of for startups. success, the hardware testing your He stresses the and software aspects of prototype. This importance of last phase of having program prototyping must work closely the prototyping management together.” program, which that really is covered in understands the engineering issues the next article, involves testing the and works with the teams. “We design’s operational capabilities and have to make sure that design market viability. reviews and the schematic reviews happen,” he says. “These are not just checklist activities. There needs to be a secondary review for the next prototype. It needs to happen in stages with each prototype.” Managing the development process well is the key to a successful prototyping program.

allows you to step through code and functions are switched on or off. A Part of the challenge for embedded observe hardware states. Gujarati simple multimeter would suffice. In developers relates to another explains, “As you write code, you more complex systems you may fundamental difference between want to be able to stop the program, need to look at more variables and embedded development and app mid-execution, and check that signal levels. For example, in a power development. Embedded software everything is in the state that you control system, you may need to look developers are constrained by expect it to be, look at the status of at complex AC to DC conversion hardware. Their reality is that hardware, the variables, registers, waveforms, power levels, phase hardware is selected and configured and other things.” shifts, and view those changes in first, and then software makes it nanoseconds. This would require a work. If a piece of hardware does not There are different methods for doing scope. operate as expected, or it changes this. Some use in-circuit emulators, in a way that causes something while others use on-chip debugging Keeping Software Development else to stop working, the general functions in conjunction with a joint in Sync with Prototype Iterations attitude is the problem will get fixed test action group (JTAG) interface. with software. Gujarati says, “We Keeping hardware and embedded JTAG is a standard interface used for often have to come up with novel software development in sync can programming, testing, and debugging techniques to make things happen be a challenge, especially if you found on many microcontrollers. the way they were meant to. It’s a are working through an aggressive Analog Devices Inc. Analog Devices Inc. Other commonly used tools include a very hacky process in that sense.” prototyping schedule where changes multimeter or a scope, depending on 3D TOF Development Platform EVAL-ADPD4000Z Evaluation Board are being made. However, for the the application. For instance, in many The key to keeping a prototyping project to be a success, the hardware consumer applications you may only program on track is having strong and software aspects of prototyping be interested in knowing if certain program management from the very mouser.com/adi-ad-96tof1-ebz-platform mouser.com/adi-eval-adpd4000z-evaluation-board must work closely together.

37 38 Prototyping: The Art of Putting It All Together

By Mouser Electronics with Mike Reed, Mechatronics Engineering Lead at HAX

39 40 market questions in order to turn a POC into a product, needed to get to those next levels. For some innovations, PROTOTYPING: THE ART OF PUTTING IT which is the purpose of prototyping. the most challenging questions are engineering in nature (Figure 1). These engineering questions may include ALL TOGETHER Getting to that first testable prototype involves continuing “What technology is best?” and “How do you get it all into work started in the POC phase. Typically, you work on the package?” For others, customer usability is a larger By Mouser Electronics with Mike Reed, Mechatronics Engineering Lead at HAX different aspects of the design, and maybe build prototype question. The prototyping program must address each sections, ultimately working toward a stage where you of the fundamental questions and take into account cost, have a looks-like and a works-like prototype that you can which is always a key factor. begin testing to answer key questions. When putting together a prototyping program, the first Mike Reed is an Australian Mechatronics engineer based in Shenzhen, China. As program director with HAX A prototyping program answers questions, which thing you need to do is decide what questions you must Accelerator, he helps hardware startups design, manage, and manufacture products ranging from the fields of might include things like how you build a product that answer, and what metrics you will measure to determine Medtech, to infrastructural IoT and industrial robotics. His major focus for the last 5 years living and working achieves the engineering requirements, how you make the answers. More specifically, each prototyping phase a product that people are happy to use, and how you will be driven by a core question, and part of designing a in Shenzhen has been optimizing the development and prototyping process for local and international startup make a product that works without being too costly for prototyping program is deciding not only what questions companies. Having multidisciplinary engineering and business planning experience with ~100 hardware startups customers. Are you ready to commit to building 100 you must answer, but which questions you need to paired with proficiency in spoken Mandarin allows him to jump in and add value at any stage of the development of units, or 1000 units, or 10,000 units, or more? Everything answer first. The ordering of key questions is very a hardware based business. you build from this point on is a prototype designed to important. Reed notes, “You should test questions that take you to the next level. As Mike Reed (Mechatronics are fundamental to the whole process of your design as Engineering Lead at HAX) explains, “Everything you make early as you possibly can. Those are often not engineering is a prototype for the next stage. You should always be questions.” Answering those fundamental questions Why You Need Prototypes pushing to get to that next stage as early as possible. can avoid backtracking later or making big, late-stage It typically begins with a proof of concept (POC) that Innovation is more than just coming up with an idea. It That’s why you’re making prototypes. They are like steps engineering changes just when you think you are ready to provides a level of idea validation. The POC is the starting is turning that idea into something real, and for many on the ladder to actually shipping a product.” begin manufacturing. Reed emphasizes the importance point for serious discussion and serious work. A POC is innovators, that reality is a product they can profitably of early testing. “One of the things that we push for with the thing that attracts the attention of potential partners manufacture and sell. Building prototypes is a key step in Designing a Prototyping Program our companies is to get testing in the field as early as and opens doors to hardware accelerators. From there, it reaching that goal. possible,” he says. is necessary to answer many engineering, usability, and Every product idea comes with its own fundamental questions that define the kind of prototyping program

Figure 1: Team of engineers working on their prototype. [CONT’D ON NEXT PAGE]

41 42 DEVELOPING A PROTOTYPE PROGRAM

By Jeff Hutchings

Developing a prototype program Prototyping is about questions: Advantages of Prototyping Avoiding feature creep during prototyping Prototypes help you come up with new ideas When making a prototyping plan, it’s important to Here are some of the key benefits of a well-run Feature creep can threaten the success of a and discover problems at an early stage. You can do these things to make sure you are answering prototyping program: prototyping program. Here’s how to avoid it: reduce costs and development work by being more right questions: agile at the beginning of product development, • You get feedback from users early enough in the • Be brutally rigorous and consider using an agile especially when you involve users early on in the 1. Choose the questions you have to answer. project to address unanticipated needs or valuable scrum style approach to keep the team focused development. 2. Consider the order of questions and focus on feature improvements. on the critical must haves from the consumer fundamental design features first. perspective. This will help developers maintain “The primary goal of a prototyping 3. Decide what metrics will be measured to • Focus on getting testing in the field as early as focus on the real purpose of each prototype. answer the questions. possible so that the user and the developer can program should be to answer, as fast as confirm that the product matches specifications. • When involving users in testing, make sure possible, the most critical questions or that they realize that the overall quality of the “When putting together a prototyping • Prototyping allows the designer to verify that prototype is not the finished product. unknowns, be they around feasibility or program, the first thing you need to product estimates are accurate and that milestones desirability.” will be met. • A minor feature addition could have a huge do is decide what questions you must effect on other parts of the project. Balance new answer, and what metrics you will features against the cost of making this change measure to determine the answers.” and the value it brings to the product.

prototype, the kind of feedback you are seeking, and That is the best way to determine if a system is really Reed recently completed working with a company that There is no one-size-fits-all prototyping program that potential risks of exposing an early stage product to the working.” If that is not possible, you should at least have is a great example of why early testing is so important. works for every product, but Reed suggests several key market. You can play it safe by using a friend or someone testers in your target market who are readily accessible. The company was developing an automated steam strategies that help to get the most out of prototyping: in your office, but the feedback you get will be biased. The very worst situation is having test subjects who cleaning device that would clean and press lightly worn “If you’re testing with people in your office, and you are not really in your target market and not available to clothes in five minutes. Their plan was to market their • Every prototype should focus on a defined question. make a really bad mistake, you’re not going to harm your continually test as you iterate prototypes. service to business travelers and deploy their devices in “As soon as you sort out exactly what specific question company reputation,” says Reed. “But the information hotels. Their design included an individualized access you need to answer, you then need to build your that you get out of that kind of test is going to be less Although and payment mechanism. As part of their prototyping prototyping scheme around that one question,” says • Do not over-structure the test procedure. valuable.” the goal of each prototype is to answer specific design program, they started advertising to potential customers. Reed. There will be many things you need to test, questions, it’s important not to structure the testing too They were immediately contacted by people in the show including component performance, power supply, narrowly around those questions. Being overly directive business industry who had problems cleaning costumes mechanics, form factor, and user experience. Depending “There is no one-size-fits-all prototyping in the kinds of feedback you seek can actually bias the fast enough to keep up with costume changes. This group on how you define your prototypes, each prototype will program that works for every product...” results. Reed suggests, “If you have a hardware product was willing to invest a lot of money if the company could have specific test objectives that will culminate in the and you have testers in your target market, sit them in a provide a solution that cleaned garments quickly. That next stage of product development. You will likely have Reed believes the best test scenario is having testers room, put the product in front of them, and say, ‘Use the instantly changed their business model and what they multiple prototypes, and each prototype will serve to who actually pay for and use the product. It might be product.’ Then see what they do.” thought was going to be their big design challenge— resolve specific design questions that get you closer to a a minimum viable product (MVP), or a functional beta the individualized payment system. That was no longer manufacturable product. version, but if people buy it and use it, their feedback There are certain kinds of structured tests that can be necessary in the theater wardrobe application, which will be honest. “The ideal is that you have fresh eyes valuable. For instance, if you are developing a product • Make testing as close to real user and market actually simplified their design. Now they had a real whenever you can, they are within your target market, that will directly compete against another existing conditions as possible. When running a prototyping customer willing to pay for further development of the and they’re paying for the actual service or product product, you can select testers who are familiar with program, you need to select testers and create test product. “If you structure those tests correctly, you will that you’re providing,” Reed explains. “Users of pilot the competitive product and set them up to use your conditions that deliver unbiased feedback. Who you clearly find out what people are willing to buy,” Reed says. products in the field are beta testers paying you money. prototype, asking them to compare the two. If you are select for testers depends a lot on the condition of the

43 [CONT’D ON NEXT PAGE] 44 in a business-to-business (B2B) situation where you should go. They plan on doing additional engineering are building the product for a customer who is also work and then building their first prototype after three an investor, you will work closely with them to define months or so, but he believes you should begin testing prototypes and test parameters. as soon as you’ve made something, working through as many prototypes as you possibly can. However, he Still, the goal should be to choose people and create a recognizes in certain industries and business cases, testing scenario that is as close to an actual customer- you need to be careful about damaging customer service, after-sales relationship as possible. The more trust. Reed advises, “If it’s at a stage where you’re not forced you make it, the less true the information will be, embarrassed by someone seeing it and you’re not and that can prevent you from seeing possibilities that concerned for someone’s safety if they use it, then you you may have missed in earlier stages. should immediately begin getting people to test it.”

• Make as many prototypes as you can. The goal of • Avoid Feature Creep. Each prototype focuses on a key a prototyping program is to finalize product design, question, and resolving those questions is the primary but also to begin building market awareness and objective. Not all feedback provided by testers will be even start generating revenue. The faster you can of direct use. As you evaluate feedback, it’s important get to revenue generation, the better your chances of to think about it in the context of what people are willing success. Technologies such as 3D printing and rapid to spend on your product. For instance, if a tester PCB fabrication have made prototyping faster and less working with an MVP version of your product complains expensive. about the lack of a feature, but they are still buying the product, their feedback is important, though you wouldn’t Reed says that many people come to him with a necessarily rush to include that feature in the next preconceived notion of how their prototyping plan prototype iteration.

Figure 2: Putting together your own prototype can give you a better idea of where problems may occur.

You may not be able to act on all the tester feedback you From Prototyping to Manufacturing receive, but don’t discard it. That information is gold. At Making a lot of prototypes and making them quickly is some point, it may make sense to tackle those issues. very important. In many cases, that means spending more money on prototypes. If some questions can be answered Why You Need To Be Intimately Involved in Building without a prototype, that’s great. An example of this might Your Own Prototypes be whether to spend more time on engineering vs. more Some innovators approach their prototyping program money on a more expensive component. Still, you’ll need assuming they need to arrange for someone to take care to get to the point where you are ready to move up the of all the details of building their prototypes. It is true that ladder, closer to revenue generation and manufacturing. as the program progresses, for the sake of organizational efficiency, innovators need to extract themselves from How do you know if your prototyping program has every detail of the process—but it is also essential that reached that point? Moving from prototyping to they know how the thing they are testing goes together. manufacturing is a big jump. When you are prototyping, you can quickly iterate design modifications. The person who spends the time soldering it together will have a feel for where problems may occur, and they Manufacturing is a commitment to tooling, which also is a will have a sense of what can and cannot be done in the commitment to freezing the design for a longer period of next design iteration (Figure 2). Reed believes the closer time. The best indicator that you have reached that point you are to the physical building of prototypes, the better, is the kinds of questions you are trying to answer with Molex Nano-Fit Molex Ultra-Fit as long as you also have a strategy for handing it off to your prototypes. If you have resolved engineering issues 2.5mm Power Connectors Power Connectors someone after you understand it. When is the right time and you are focusing on customer satisfaction questions, to step back? Reed says, “If you’re intimately familiar with and you have strong indications people will buy the the way everything works and you know that you can do product as it is, then it is time to think about tooling and mouser.com/molex-nanofit-power-connectors mouser.com/molex-ultra-fit-power-connectors it well yourself, that’s when you ask someone else to do it designing for manufacture. for you.” 45 46 E N G I N E E R I N G

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