DAq

DAq uses a Raspberry Pi 3 and various sensors to collect car performance data.

The data points collected are:

• Engine load (%)
• Coolant temperature (°C)
• RPM (RPM)
• Speed (MPH)
• Intake temperature (°C)
• MAF (grams/sec)
• Throttle position (%)
• Timing advance (° before TDC)
• Acceleration (Gs)
• GPS position

Hardware Components

• Raspberry Pi 3
• MMA8451 Accelerometer (I2C)
• Ultimate GPS Breakout V3 (miniUART)
• OBDII ELM327 (Bluetooth)

Raspberry Pi 3 Setup

Additional Packages

# OBD python library
sudo pip install obd

# I2C support
sudo apt-get install python-smbus

# GPS support
sudo apt-get install gpsd gpsd-clients python-gps

Changes to sudo raspi-config

• Enable I2C
• Enable Serial

Setup Bluetooth OBDII

bluetoothctl
power on
agent on
scan on
# Look for OBDII <MAC>
pair <MAC>
trust <MAC>
quit

Setup Serial GPS

Remove reference of serial0 from /boot/cmdline.txt:

dwc_otg.lpm_enable=0 console=serial0,1152 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait

to:

dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait

edit /etc/default/gpsd:

START_DAEMON="true"
USBAUTO="false"
DEVICES="/dev/ttyS0"
GPSD_OPTIONS="-n -G"

for older Pi's please refer to link for setup: https://learn.adafruit.com/adafruit-ultimate-gps-hat-for-raspberry-pi/pi-setup

Add the following lines to /etc/rc.local

# Needed to connect bluetooth to serial port
# 00:1D:A5:00:17:08 is the MAC address of the OBDII bluetooth device
# & is needed to fork this call because it doesn't return (blocking call)
sudo rfcomm bind rfcomm0 <MAC> &

# Setting up I2C
sudo chmod 666 /sys/module/i2c_bcm2708/parameters/combined
sudo echo -n 1 > /sys/module/i2c_bcm2708/parameters/combined

Reboot Pi:

sudo reboot

If your GPS has a fix then running cgps -s should result in some GPS relate data.