Design Constraint Presentation Team 5: Sports Telemetry Device

Project Overview Measure impacts experienced by football players to monitor and detect potential brain injury Communicate measurements to sideline over mesh network Analyze collected data as game progresses using research done by the Purdue Neurotrauma Group

Microcontroller Design Constraints Basic computational requirements – Continuously sample accelerometers/gyros, store to NAND flash, send to sideline Peripheral Requirements – SPI (Wireless Module), ADC (Sensors), USB Interface (Data retrieval/charging), Timer Module External Interfacing Requirements – Sensors Three 3-axis accelerometers (analog) Two 2-axis gyroscopes (analog) 2kHz sampling rate, preferably 12-bit resolution – NAND Flash memory >= 8Gb Ultra-fast read/write – Three capacitive sensors (power on/off) – RF Module Low power consumption – Battery must last (at minimum) the duration of a football game Low cost – Affordable for majority of families

Microcontroller Candidates Atmel ATxmega256A3BU – Max I/O pins: 47 – SPI channels: 8 – ADC channels: 16, 12-bit – ADC sampling rate: 2kHz – Extras: USB interface, temp. sensor, timer module, low power – Lacks: NAND interface PIC24HJ64GP206A – Max I/O pins: 85 – SPI modules: 2 – ADC channels: 32, 10-bit – ADC sampling rate: Up to 1.1MHz – Extras: Idle/Sleep/Doze modes – Lacks: NAND interface

Wireless Module Design Requirements Small footprint Minimum 60m range Low power consumption – Sleep mode, if possible Robust protocol supporting: – Self-organizing mesh network – Network self-healing Operation within ISM radio band (2.4GHz) At least 200kbps transmission rate, ideally

Wireless Module Candidates XBee XBP24BZ7PIT-004 – Frequency band: 2.4GHz – Line of sight range: 300ft (~90m) minimum – Supply current: {xmit: 205mA, rec.: 47mA} – Data rate: 250kbps – Dimensions: 33mm x 24mm x 3mm – Interface: UART – Notes: Requires bulky antenna, supports robust mesh network Atmel ATZB-24-A2 – Frequency band: 2.4GHz – Line of sight range: ~50m minimum (based on TI) – Supply current: {xmit: 18mA, rec.: 19mA} – Data rate: 250kpbs – Dimensions: 24mm x 13mm x 2mm – Interface: SPI, UART – Notes: compact onboard antenna, supports robust mesh network, interfaces easily with Atmel ATxmega256A3BU microcontroller