Mark Sears
John Jachna
Jordan Wagner
Justin Spencer
Outline










Project overview
Project-specific success criteria
Block diagram
Component selection rationale
Packaging design
Schematic and theory of operation
PCB layout
Software design/development status
Project completion timeline
Questions / discussion
Project Overview
Our team is implementing a smartphone controlled marble maze. Players
guide a marble through a maze by controlling the degree of tilt of the
playing surface via a wireless link to a smartphone. The accelerometers in
the smartphone capture the players' input and relay it to the game
controller. The game controller then adjusts the tilt of the playing surface via
stepper motors on each axis.
Project-Specific Success Criteria
1. An ability to manipulate the playing surface via stepper motors.
2. An ability to control the playing surface with accelerometers in an iPhone
and resistive joysticks.
3. An ability to detect the player's failure or success using IR gates.
4. An ability to display game statistics & configuration information on an
LCD and play game related tones on a speaker.
5. An ability to store separate, specific game data on the board and on the
iPhone.
Block Diagram
Microcontroller Choice
PIC18F67J94
• Fast clock speed, up to 64 MHz
• Many serial communications options – 4 USART and 3 SPI/I2C channels
• Large flash memory – 128KB
• Copious amounts of analog and PWM channels, as well as plenty of GPIO
pins – 64 pin package
Image source:
http://ww1.microchip.com/downloads/en/DeviceDoc/30575A.pdf
Motor Choice
Reliapro 39BYG001-R (5V, 1A)
• 5V power supply, no need for an extra regulator
• 1.8° step angle – small steps for fine tuned board control without the
need to add gears
• 2 phases – compatible with most stepper motor controller ICs
Image source: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_237490_-1
WiFi Interface Selection
Raspberry Pi
• Many configuration options for changing settings without
reprogramming microcontroller
• Low cost with large amounts of documentation/resources
• Easy to prototype and test without the microcontroller
Image source: http://www.geeky-gadgets.com/wp-content/uploads/2012/07/Raspberry-Pi2.jpg
Packaging Design
- Stock
Packaging Design
- Modified
Schematic/Theory of Operation
- Overview
Schematic/Theory of Operation
- Power Supply
LM2576 Step-down (buck) switching regulator
Schematic/Theory of Operation
- Stepper Driver
Schematic/Theory of Operation
- Headers
PCB Layout
- Overview
PCB Layout
- Power Supply
PCB Layout
- Stepper Driver
PCB Layout
- Headers
Software Design/Development Status
• Microcontroller: prototyping on development board,
several on-chip peripherals functioning.
• Microcontroller works as a polling loop that waits on
packets from the Raspberry Pi
• Raspberry Pi: Server code functioning, receiving
packets from iPhone in 1.66 ms. Wireless is set up.
• iPhone: Sending data to Raspberry Pi successfully. App
also grabs rotation degree from internal accelerometer
and gyroscope.
PIC Microcontroller Software Flowchart
Project Completion Timeline
• Week 8 – Program RaspberryPi, Formal Design Review
• Week 9 – Finalize PCB, Order all remaining parts, Software development
(ongoing), Prototype power supply, Proof of Parts
• Week 10 – Spring Break, PCB manufactured
• Week 11 – Populate PCB in units, burn-in power supply, Software Design
Narrative
• Week 12 – Debug Hardware, Program microcontroller, Attach sensors &
motors to chassis, Patent Liability Analysis
• Week 13 – Debug Microcontroller, Finalize iPhone application, Develop
control algorithms, Reliability & Safety Analysis
• Week 14 – Debug iPhone app, Debug iPhone -> RaspberryPi ->
Microcontroller communication chain, Ethical & Environmental Impact
Analysis
• Week 15 – Debug, Documentation, Finalize packaging, User Manual
• Week 16 – Debug, Prepare for PSSC Demonstration
Questions?