
FLIGHT DATA RECORDER FOR THE AMERICAN FOOTBALL Mechanical Engineering Final Project Masters of Engineering Chris J. Nowak
Project Introduction Why Put something like this… in something like that?
Background Information • Accelerometer • ADXL250 • +/- 50g Sensitivity • Microcontroller • PIC16F876 • 20Mhz • 5 Internal A/D converters • Flash Programmable • SEEPROM • AT25640 • Memory Device that can store 4096 bytes of data • SPI interface
Accelerometer Information • ADXL250 • +/- 50g Sensitivity • Analog Output • 0.39g Resolution as Configured • Can be increased by scaling the total range • 8-bit Data Points
Microcontroller Information • PIC16F876 • Programmed in PicBasic Pro
Electronics “Plan – A” • 1 Microcontroller – PIC 16F877 • 4 Accelerometers – ADXL202, ADXL210, ADXL250 • 8 x 128k SRAM Memory Accelerometers SRAM Microcontroller
Electronics “Plan – B” Microcontroller • 4 Identical Modules • 1 Microcontroller – PIC16C717 • 1 Accelerometer – ADXL250 • 2 32k SEEPROM Memory Chips • Simple Modular Design • Poor Selection of Microprocessor SEEPROM Accelerometer
Microcontroller Accelerometers SEEPROMs Final Electronics Layout • 2 Identical Modules • 1 Microcontroller - PIC16F876 • 2 Accelerometers – ADXL250 • 4 SEEPROM Memory Chips – AT25640
Installation in the Football • Plan A used a modified hard plastic “Football Phone” • Plan B was abandon prior to packaging • Plan C used a modified “Nerf” football
Test Matrix • Collect a 1g baseline data set by holding the ball so the X, Y, and Z axis were each subjected in turn to the Earth’s gravity • Throw football in a tight spiral • Lob football in and end-over-end tumble
Test Results • Baseline Data
Test Results • Forward Pass
Test Results • End-Over-End Tumble
Design Recommendations • Improve PC-Football Serial Interface • Reduce the weight of the electronics by using more surface mount components • Reduce size/weight of batteries or find alternative power source • Add additional EEPROM chips to increase sample rate • Scale accelerometers to +/- 15 G’s
Flight Data Recorder for the American Football ANYQUESTIONS??