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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