SECON 2012Midterm Presentation

Meet the Team

Michael HelmbrechtElectrical Engineer• Measurement Tasks• Course Construction

Chris NicholasComputer Engineer• Measurement Tasks• Course Construction

Kristin SharpElectrical Engineer• Measurement Tasks• Course Construction

Ryan RougeauElectrical Engineer• Navigation• PCB Design

Erin TateElectrical Engineer• Navigation• PCB Design

Jason WarrenComputer Engineer• Navigation• PCB Design

Dr. Robert ReeseAdvisor

Outline

• Competition Overview• Project Overview• System Design• Design Constraints• Approach & Tradeoff Analysis• Timeline• Progress and Prototype

Competition Overview

• IEEE SoutheastCon 2012 Hardware Competition• Orlando, FL• March 15-18, 2012• Autonomously navigate a course using the results of four tests to guide path.[1]

Outline

• Competition Overview• Project Overview• System Design• Design Constraints• Approach & Tradeoff Analysis• Timeline• Progress and Prototype

Project OverviewFeatures:

• Modular/Easy to Repair• Battery Life of 12 Minutes

Specifications:• Detects voltages• Detects plate temperature

• Detects capacitance• Differentiates between square and sawtooth waveforms• Autonomous after startup• Makes decisions based on measurements

Outline

• Competition Overview• Project Specifications• System Design• Design Constraints• Approach & Tradeoff Analysis• Timeline• Progress and Prototype

System Design

Microcontroller LocomotionMeasurement

Debug Info

Microcontroller

Voltage Measurement

Waveform Analysis

Capacitance Measurement

Temperature Sensing

Measurement System Design

Microcontroller

Encoders

Wall Sensors

Line Sensors Motors

Locomotion System Design

Outline

• Competition Overview• Project Overview• System Design• Design Constraints• Approach & Tradeoff Analysis• Timeline• Progress and Prototype

Design Constraints – Practical Name Description

Voltage Measurement

The robot must be able to make voltage measurements between 0V and 15V with an unknown polarity. The robot must be able to differentiate between voltages of less than 9V and those of greater than 11V.

Waveform Analysis

The robot must differentiate between saw-tooth and square waves with frequencies on the order of 100kHz and RMS voltage of 5V.

Capacitance Measurement

The robot must be able to measure an unknown capacitance between 10µF and 10nF. The robot must be able to differentiate between capacitances of less than 100nF and more than 1µF.

Temperature Measurement

The robot must be able to take a temperature measurement and decide whether that temperature is within 10⁰F of ambient room temperature.

Navigation The robot must be able to navigate the course autonomously using provided lines and hash marks. The robot must be able to complete at least two laps without error.

[1]

Design Constraints – Practical

Type Name

Manufacturability Modular Design

Sustainability Troubleshooting

Practical – Modular Design

• The robot must be designed to allow for quick and easy replacement of malfunctioning components– Coding– Hardware

Practical – Troubleshooting

• The robot must have remote debugging capabilities

Outline

• Meet the Team• Competition Overview• Project Overview• System Design• Design Constraints• Approach & Tradeoff Analysis• Timeline• Progress and Prototype

Four Measurement Tasks

• Measurement of Capacitance• Measurement of Voltage• Measurement of Temperature• Waveform Detection

Capacitance Measurement

CHOICES PROS CONS

RC Time Constant Quick and accurate. Relies on a timer

Capacitance Measurement

Measuring capacitance with RC time constant [2]

Capacitance Measurement

CHOICES PROS CONSParallel Capacitance The circuit, concept,

and code were simple.More components

Capacitance Measurement

Parallel Capacitance Measurement

Formula: C2 = ((Vref * C1)/ADC_IN) – C1

Capacitance Measurement

CHOICES PROS CONS

Parallel Capacitance The circuit, concept,and code were simple.

More components

RC Time Constant Quick and accurate. Relies on a timer

Voltage Measurement

CHOICES PROS CONS

Voltage Divider and Rectifier

Quick and simple. 123 ADC counts per volt

Voltage Measurement

Voltage divider

Thévenin Equivalent Shifter

Noise Capacitor

Voltage Measurement

@-15V

0V

@15V

3V

@0V

1.5V

Voltage Measurement

CHOICES PROS CONS

Operational Amplifier and comparator

Distinguishing between voltages is simple.

The circuit and coding is more complex than a voltage divider.

Voltage Measurement

CHOICES PROS CONS

Operational Amplifier and comparator

Distinguishing between voltages is simple.

The circuit and coding is more complex than a voltage divider.

Voltage Divider and Rectifier

Quick and simple. 123 ADC counts per volt

Temperature Measurement

CHOICES PROS CONS

Probe Accurate. Requires precise robot alignment.

IR Sensor Faster since no contact needed.Can sense from a distance.

Less accurate (±1°F).

Laser Accurate from a distance. Expensive and large.

Temperature Measurement

CHOICES PROS CONS

Probe Accurate. Requires precise robot alignment.

IR Sensor Faster since no contact needed.Can sense from a distance.

Less accurate (±1°F).

Laser Accurate from a distance. Expensive and large.

Waveform Detection

CHOICES PROS CONS

Edge Detection Uses only µC. Wave frequency too high for µC.

Comparator Works at all frequencies. Circuit is more complicated.

Waveform Detection

Output waveform

Input waveform

Vref

+

-

Waveform DetectionSquare Wave Sawtooth Wave

Vref

Waveform Detection

CHOICES PROS CONS

Edge Detection Uses only µC. Wave frequency too high for µC.

Comparator Works at all frequencies. Circuit is more complicated.

MicrocontrollersCHOICES PROS CONS

2x PIC24 28 PIN Microcontrollers

- Easy parallel development phase.

-Lower usable pin count.- Communication between PICs requires code/time.

1x PIC24 64 PIN Microcontroller w/ breakout

-Higher usable pin count.-No extra coding.- Proven use.

- More difficult to develop in parallel.

MicrocontrollersCHOICES PROS CONS

2x PIC24 28 PIN Microcontrollers

- Easy parallel development phase.

-Lower usable pin count.- Communication between PICs requires code/time.

1x PIC24 64 PIN Microcontroller w/ breakout

-Higher usable pin count.-No extra coding.- Proven use.

- More difficult to develop in parallel.

MicrocontrollersCHOICES PROS CONS

PIC24F16KA102 28 PIN - Has onboard capacitance measurement hardware.- Lower power than PIC24HJ.

- Slower clock frequency than PIC24HJ .- Only 28 pins.

PIC24FJ64GA002 28 PIN - Lower power than PIC24HJ.- Had a few on hand.

- Slower clock frequency than PIC24HJ .- Only 28 pins.

PIC24HJ128GP506 64PIN -Has as much memory as 2 PICFJ64 series.- Faster clock speeds.- 64 pins

- Needs a break out board to maintain modularity.

MicrocontrollersCHOICES PROS CONS

PIC24F16KA102 28 PIN - Has onboard capacitance measurement hardware.- Lower power than PIC24HJ.

- Slower clock frequency than PIC24HJ .- Only 28 pins.

PIC24FJ64GA002 28 PIN - Lower power than PIC24HJ.- Had a few on hand.

- Slower clock frequency than PIC24HJ .- Only 28 pins.

PIC24HJ128GP506 64PIN -Has as much memory as 2 PICFJ64 series.- Faster clock speeds.- 64 pins

- Needs a break out board to maintain modularity.

ChassisCHOICES PROS CONS

Stinger Robot Chassis

-Was given to us.- High torque motors.- Robust design

-Rear of chassis swings when turning.- Too large.

DFRobot 2wd Mobile Platform

-Round design.- Faster motors.

- Delay on order.

ChassisCHOICES PROS CONS

Stinger Robot Chassis

-Was given to us.- High torque motors.- Robust design

-Rear of chassis swings when turning.- Too large.

DFRobot 2wd Mobile Platform

-Round design.- Faster motors.

- Delay on order.

Wall Sensors

CHOICES PROS CONSSharp 2D120X Infrared Sensor

Shorter Distances (4 – 30cm) Only detects out to 30 cm.Interference when teaming.Only analog output.

Maxbotix LVMaxSonar-E4 Sonar Sensor

Longer Distances (6 - 254 inches)UART , PWM, and Analog outputNo interference when teaming

Only detects down to 6 inches.

Wall Sensors

CHOICES PROS CONSSharp 2D120X Infrared Sensor

Shorter Distances (4 – 30cm) Only detects out to 30 cm.Interference when teaming.Only analog output.

Maxbotix LVMaxSonar-E4 Sonar Sensor

Longer Distances (6 - 254 inches)UART , PWM, and Analog outputNo interference when teaming

Only detects down to 6 inches.

Motors

CHOICES PROS CONS35:1 Metal Gearmotor 15.5Dx30L mm

Higher RPM (460 RPM)Low locked current (0.6A)

Low Torque (13 oz-in)

Micro DC Geared Motor FIT00016

Medium Torque (26.6 oz-in)Medium RPM (200 RPM)

High locked current (6A)

Motors

CHOICES PROS CONS35:1 Metal Gearmotor 15.5Dx30L mm

Higher RPM (460 RPM)Low locked current (0.6A)

Low Torque (13 oz-in)

Micro DC Geared Motor FIT00016

Medium Torque (26.6 oz-in)Medium RPM (200 RPM)

High locked current (6A)

Outline

• Meet the Team• Competition Overview• Project Overview• System Design• Design Constraints• Approach & Tradeoff Analysis• Timeline• Progress and Prototype

TimelineAugust September October November December

Strategy and Course Construction

Research and Purchasing

Programming

Circuit Design

Debugging

Prototype

Outline

• Competition Overview• Project Overview• System Design• Design Constraints• Approach & Tradeoff Analysis• Timeline• Progress and Prototype

Course Construction

Initial Prototype

Initial Prototype

Locomotion Prototype Circuit• Gyroscope

• Bluetooth Transceiver

• MCU

• Motor Controller

Measurement Prototype Circuit• Voltage Divider

and rectifier

• Parallel Capacitance Circuit

• Infrared Temperature Sensor

Software Debugging

Circuit Testing

Decision Circuit

Decision Circuit

References[1] IEEE SoutheastCon 2012 Hardware Competition. “Release 1.0." 30

Sep. 2011. https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0BwrmPsE7PwUQMThkMzk4NDUtNzAwYy00YzFjLTg1ODMtNWJmMjg0NGVkYjM5&hl=en_US

[2] Embedded Lab “How to measure capacitance with a microcontroller?” 5 Oct. 2011.

http://embedded-lab.com/blog/?p=1747

SECON 2012Midterm Presentation