Team Introduction

Rahul Sachdeva Senior, Computer Engineering National Center for Supercomputing Applications

Bjorn Oberg Senior, Electrical Engineering US Army Construction Engineering Research Laboratory

TA: Nicholas Ratajczyk

1 Client Agenda Logo

Project Introduction 3

Features 4

System Overview and Block Diagram 5

Metal Detection Module 6

Retrieval Unit 13

Power Module 19

Navigation Unit 22

Control Unit 25

Conclusion 30

2 Project introduction: Problem Statement

How can we create an inexpensive solution to finding and disposing off potentially hazardous objects?

2 1 A remote controlled car A user friendly solution that can be used in the lab that can also be used for and homed to find metallic leisure and treasure objects detection

3 A solution that can be expanded and made robust to potentially help EOD teams

RACE: Remote Area Clearance devicE

3 Features

§ A metal § A brush and detection circuit scoop retrieval based on Metal Object system Colpitts Detection Retrieval Oscillator design

Android Live Video App to Feedback control § An Android § Live video Application to feedback over Operation control the robot Wi-Fi Precise Expandabl Navigatio e Design n § Strong, metallic § Built-In depth design with analysis and wheel tracks, to facial recognition withstand any capabilities rough terrain

RACE is a remotely controlled robot that can be used to look for metallic objects, and retrieve those from the ground. 4 Block Diagram

5 Metal Detector Module Metal Detection Unit

• The Colpitts Oscillator produces Colpitts Oscillator 1 a signal of 100kHz.

• 50 turns of wire wrapped around 2 Detector Coil a spool of radius 2 inches

• When the change in frequency is higher than a threshold, a signal 3 Microcontroller is communicated to the mobile app via Bluetooth

A metallic object causes the inductance of the detector coil to change, which causes a change in the frequency read by the microcontroller 7 Metal detector – Circuit design

Relevant Equations

×× ×× F = L = B = ×× ×

When near a metal, the change in the magnetic permeability of the core causes a change in the inductance, which changes the output frequency 8 Oscillator performance

Test Cases

§ Small Object: Brass § Large Object: Brass cube of volume 0.763 Cylinder of volume square inches 17.07 square inches (1.2×0.6×1.06(�× �×�))

Inductance Capacitance Observed Fluctuation Change due Change due Frequency % to small to large object (at 2 object (at 3 cm) cm)

0.546 mH 5 nF 98.614 kHz 0.57% - 1.92% 0.546 mH 2.5 nF 143.4 kHz 0.88% 1.02% 2.38% 10 mH 5 nF 21.8 kHz 0.49% - 1.14% 10 mH 2.5 nF 36.2 kHz 0.66% - 1.34% 10 mH 235 pf 94.4 kHz 0.84% 1.17% 2.37%

Higher frequencies and stronger magnetic fields are better at detecting metal; however the effect of frequency is greater than the strength of the magnetic field 9 Oscillator Test with Large Object

% Change In Frequency v/s Distance frequency from

110 Ceiling (3cm) 1.8 108 1.6 106 1.4 104 1.2 1 102 0.8 100 0.6 Frequency (kHz) Frequency 98 0.4 0.2 96 0 Infinity 5 cm 4 cm 3 cm 2 cm 1 cm Inside 10 mH 0.546 mH the core 235 pF 2.5 nF 5 nF Large Object Small Object Base Frequency + Fluctuation

While frequency changes were observed for smaller objects from as far as 5 cm away, the change was within the error margin if the distance was greater than 1 cm 10 Snapshot of Signal Changes

With a Large Metalic Object 2 cm away from Under Normal Conditions the coil

The frequency of the signal changes as a metal is brought near the inductor core

11 Challenges and Alternate Designs

1 Unable to detect smaller objects Challenges Microcontroller unable to read the correct 2 frequency

XXXXXXXXXXXX

1 Capacitive Sensing using Electric Paint Alternate Designs Tested 2 Metal detection Using IC555 Timer Chip

A design using the IC555 Timer chip was used to produce a sound directly without using the microcontroller to compare frequencies 12 Retrieval Unit Retrieval Unit

Key Components

Servo § High Torque Servo: LD-220MG 20 Kg*cm

Servo Arms § Custom sized and built to fit our robot

3D Printed Container § Custom designed using Creo Parametric CAD software § Printed by the US Army Corps of Engineers

DC Motor for Brush § High torque and high speed DC brushed motor § Runs at 10000 RPM

The servo motor is used to rotate the arms of the container, and the brush is used to scoop the object into the container 14 Physical Design

Creo Parametric CAD software was used to design the container which was then 3D printed; whereas the arms were custom made from wood 15 Client Retrieval Unit – Test Cases Logo

Thin and flat Round - able to roll Misc. Not able to roll easily Size Small Objects Small Large Objects

Small is defined as less than 1” in L, W, or H. Large is defined as between 1-3.5” in L, W, or H. Objects larger than 3.5” were not tested as they exceed the dimensions of the bucket. 16 Client Retrieval Unit – Test Results (15 Trials) Logo

Performance of Retrieval Unit 14

12

10

8

6

4

2

0 Flat - Small Flat - Large Round - Small Round - Large Misc. - Small Misc. - Large

Scooped Scooped and Lifted

If the Object was too thin, it was missed by the brush whereas if the object was too thick, the brush would get stuck. The round objects sometimes rolled out of the bucket. 17 Client Retrieval Unit Video Logo

18 Power Module Power Module

11V Li-On Battery

4.5V Regulator 7V Regulator

§ DC Motors for brush § ATMega328 § DC Motors for § LM293D H-Bridge navigation § Colpitts Oscillator § Servo Motor § HC-05 Bluetooth

2 regulators are required to supply 4.5V and 7V across all components of the circuit from an 11V power source 20 Voltage Regulator Circuit

Results

7V regulator 7.1V

4.5V regulator 4.52V

Maximum 0.6A Current draw

Design

§ The ratio of the two resistors determines the output voltage § R2 is 624 ohms and 1104 ohms for the 4.5V and 7V regulators respectively § The stability of the 4.5V regulator is important to ensure a stable current through the inductor

21 Navigation Module Navigation unit

Design

§ L293D H-Bridge to drive the two motors § 7V power input for the motors § 4.5V power for the IC chip § Port B of the Atmega328 for PWM ability

The two DC motors are driven using an H-Bridge, the signals of which are controlled by the microcontroller 23 Intel RealSense Camera

Features

§ A camera is required to provide visual feedback to the user to aid in controlling the robot § The Intel Euclid RealSense was provided to us by CERL § The camera transmits the video by over its own Wi-Fi network § Apart from an excellent frame rate, this camera has depth analysis and facial recognition capabilities, which we hope to use in the future.

The Intel RealSense was chosen due to its advanced depth analysis features, which was of interest to CERL 24 Control Unit Flowchart for Receiving Data

§ The microcontroller § The Android app sends decodes this data and data to the Bluetooth performs the required Module via UART action

HC-05 Android Bluetooth ATMega328 Application Transceiver

§ The Bluetooth transceiver receives this data over UART at 9600 BPS, and communicates it to the microcontroller

The Android app was built using MIT App Inventor and is used to communicate with the robot and control the navigation and retrieval units via Bluetooth 26 Flowchart for Sending Data

§ The Colpitts § When a change is Oscillator detected, the continuously feeds Bluetooth modules the frequency to the sends a signal to the Microcontroller App

Colpitts Android ATMega328 HC-05 Bluetooth Oscillator App

§ The microcontroller § The app alerts compares the the user by frequency with displaying a a fixed message frequency

When a metal is detected, the app receives a signal from the microcontroller, and alerts the user 27 Bluetooth Module

Design

§ UART Interface § 9600 BPS § >30 Feet Range § Voltage Divider to receive signal from Microcontroller

The HC-05 transceiver can receive data from the from a host computer over UART interface; and has a range greater than 30 feet. 28 Android App

§ List Picker for the Bluetooth § Touch Down Client to connect Buttons to to a device control the navigation

§ On click Button to control the § On click button brush to control the servo motor

The android app can connect to the Bluetooth client, and has a variety of buttons to control the car’s operations 29 Conclusion Future Steps

Object classification Alternate and facial Designs for recognition More metal robust Autonomous detection retrieval and navigation unit Proximity using depth capacitive Sensors for analysis sensing Complete semi- integration autonomous of metal navigation detector

A practical design by incorporating the features of the Intel RealSense Camera

31