FlashCarPi

utilization of a raspberry pi as a dash unit within a car

clone this environment to the RPi home directory

Create virtual environment using venv

*linux*
cd /home/flashcarpi/
python3 -m venv ./venv

*windows*
cd \path\to\project\flashcarpi
python3 -m venv venv

Get into virtual environment (venv)

once in the project folder activate the environment

*linux*
source ./venv/bin/activate

*windows*
venv\Scripts\activate

should return

(venv) pi@raspberrypi:~/flashcarpi $

check python interpreter and pip location

linux: which python should return

/flashcarpi/venv/bin/python

linux: which pip3 should return

/flashcarpi/venv/bin/pip3

windows: where python should return

\flashcarpi\venv\Scripts\python.exe

windows: where pip should return

\flashcarpi\venv\Scripts\pip.exe

Install dependencies

make sure location is set in the flashcarpi/ folder and the (venv) is active.

run pip install -r requirements.txt

check if dependencies are installed correctly

pip list should return a list of 3rd-party dependencies required for this project

Shutdown Script

move shutdowndowncheck.py to /home/pi/bin/button

tell the RPi to run the script on startup

run sudo nano /etc/rc.local in terminal to edit the file

then add the following before exit 0

python /home/pi/bin/button/shutdowncheck.py &

Setting up I2C

Open up a terminal window and type: sudo raspi-config

Choose option: 5 Interfacing Options

Choose option: P5 I2C and hit enter

Choose: to turn on the I2C interface

Choose: Ok

Choose: Finish

set dtoverlay=i2c-rtc,pcf8523 to dtoverlay=i2c-bcm2708 this is an older i2c protocol that doesnt default enable repeated start

Reboot the RPi

test with ls /dev/*i2c* it should return

/dev/i2c-1

install the i2c tools to get the command line tools needed to interact with i2c. sudo apt-get install -y i2c-tools

next test for the wired I2c devices sudo i2cdetect -y 1

it should return a grid similar to this

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- 24 -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- 62 -- -- -- -- -- UU -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --  

the garmin lidar lite has the 0x62 address

Setting up bluetooth OBD II

plug the Bluetooth OBD II into the port inside the car

then run the following commands

bluetoothctl
power on      # ensures bluetooth is on
pairable on   # ensures bluetooth is pairable
agent on      # makes pairing persistent
default-agent
scan on       # scans for bluetooth devices
              # the OBDII adapter should read something
              # like this - 00:00:00:00:00:00 Name: OBDII
              # If it asks for a pin, the default pin is 1234
scan off      #turn off scanning once your adapter has been found
pair <adapter mac address>       #pair to your adapters mac address
trust <adapter mac address>      #keeps pairing even after reboot
quit                             #exits out of bluetoothctl

OBD is a serial port we need to bind it to a port on the pi

sudo rfcomm bind rfcomm0 <adapter mac address>

to get the bluetooth adapter to connect automatically

sudo nano /etc/rc.local

then add the following before exit 0

rfcomm bind rfcomm0 <adapter mac address>

then edit the bluetooth config file

sudo nano /etc/systemd/system/dbus-org.bluez.service

find the line that says "ExecStart=/usr/lib/bluetooth/bluetoothd", and change it to this:

ExecStart=/usr/lib/bluetooth/bluetoothd -C
ExecStartPost=/usr/bin/sdptool add SP