FSAEe Data Acquisition System ECE 445 Senior Design Mohan Sha Raviraj Mahajan Mohammad Farooq Shaik TA: Ryan May Project No. 34 Spring 2013

Introduction Motivation - Formula SAEe needs DAQ system Objective - Real time display of sensor data to driver - Wireless display of data to pit crew - Store data for crew

Features Optimum response time of the sensors Data stored directly into excel sheet with time stamp Tested wireless range spans over 350 meter radius

System Overview

Schematics Tx unit

Schematics Rx unit

System Components Hardware - Power Supply - Microcontroller Unit – Arduino Uno - XBee Pro Series 1 - LCD - 5 Sensors Software - Arduino Programming Environment - Configurable with PC

Power Supply 300V to 24V to 12V provided 5V required for: - Microcontroller - Sensors - LCD 12V to 5V dc-dc conversion

Power Supply Input Voltage: 12V Output Voltage: 4.91V Duty cycle Voltage ripples: 20mV Tolerance < 2%

PCB Design for buck converter

Data On-board LCD display (for driver): – Vehicle speed – Motor temperature Wireless transmission to pit crew: – Vehicle speed – Motor temperature – Motor speed – Battery voltage – Coolant temperature

Motor Temperature Sensor - Analog - 5.0V input - o C = 100V-50 - ±2 o C in -40 to 125 o C

Documented Observed Output Voltage vs. Temperature Motor Temperature Sensor

Average Error = ~ 5% = 3 o C Motor Temperature Sensor Sensor Temperature vs. Thermometer Temperature

Coolant Temperature Sensor - Digital one-wire - Waterproof - 5.0V input - ±2 o C in -55 to 125 o C

Average Error = ~ 5% = 2.45 o C Coolant Temperature Sensor Thermometer Temperature vs. Sensor Temperature

Speed Sensor Wheel and motor speed - Hall Effect o C to +150 o C - 5V input (1kΩ pull up resistor) - 10µs rise/fall time - Maximum speed 10kHz Target - Magnet or magnetic metal - Tooth height: 0.2 in - Tooth width: 0.1 in - Tooth separation: 0.4 in - Tooth thickness: 0.25 in

Speed (Hall Effect) Sensor

Average Error = ±16 RPM Speed (Hall Effect) Sensor Stroboscope RPM vs. Sensor RPM

Arduino Uno Arduino Uno: Atmel ATmega328 microcontroller 14 Digital I/O Pins 6 Analog Pins 16 MHz speed Voltage required: 5 V Supplies 3.3V as required for Xbee

Xbee and XBee Explorer USB XBee Pro 60mW Wire Antenna - Series 1: Range: 1 km Observed Range: 350 m Voltage Required: 3.3 V Max data rate: 250kbps Xbee Explorer USB: Transmit data received by Xbee over USB through Serial interface Gobetwino software

DAQ System

Achievements All required sensor data acquired Data successfully transmitted over XBee Data stored in Excel sheet All components successfully powered by a dc-dc converter circuit

Difficulties FIO BMS data acquisition Soldering extremely small surface mount chips (4 mm sized with 8 pins)

Further Improvements Collect and display more data - Steering Wheel Position Sensor - Tire Pressure Sensors - Lap time recorder Improve wireless range and reduce sensor output error. More efficient PCB design Integrate communication with Battery Monitoring System to read additional data

Special Thanks: Prof Scott Carney TA Ryan May ECE Parts shop staff

Questions?