Self Driving Car

First, we will be flashing an OS on the Raspberry Pi. Install Raspian Legacy. In order to actually flash the SD card, you’ll need to install a Raspberry Pi Imager. It is the software that flashes the OS. I chose the Raspberry Pi OS 32 bit, the SD card, and “wrote” it.

You then need to set up the WiFi for the first boot. On your Terminal, type the following line of code.

vi /Volumes/boot/wpa_supplicant.conf

Once it opens a file, you’ll need to copy-paste the following code, replacing the contents to match the credentials of your WiFi.

country=US
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
    ssid="<your network name>"
    psk="<your password>"
}

You then need to enable SSH on Boot. This will allow you to control the Raspberry Pi through your host PC. We will be creating an SSH file in the boot partition.

touch /Volumes/boot/ssh

Your SD card is now ready and can be ejected from your computer!

Insert the SD card in the Raspberry Pi and connect it to a monitor using a Micro-HDMI to HDMI cable. Upon booting, log in with:

• Username: pi
• Password: raspberry

Then try the following command to find the IP address of your Raspberry Pi. We will need this information in order to ssh into the Pi, which is essentially programming your Pi using the host PC.

ip -br a

To see if you found the correct number, on your Host PC, on Terminal, type:

ssh pi@<your pi ip address>

Update the software

sudo apt-get update --allow-releaseinfo-change
sudo apt-get upgrade

Configure your Raspberry Pi:

sudo raspi-config

• change the Pi’s default password for protection purposes
• change the Hostname if you’d like to
• enable “Interfacing Options – I2C”
• enable “Interfacing Options – Camera”
• select “Advanced Options – Expand Filesystem”

Once you’ve done all of these steps, land on the Finish option and press enter.

Next, you’ll need to install Dependencies.

sudo apt-get install build-essential python3 python3-dev python3-pip python3-virtualenv python3-numpy python3-picamera python3-pandas python3-rpi.gpio i2c-tools avahi-utils joystick libopenjp2-7-dev libtiff5-dev gfortran libatlas-base-dev libopenblas-dev libhdf5-serial-dev libgeos-dev git ntp

You also can install Dependencies for OpenCV. Although this isn’t required (in the case of wanting a minimal install), you can install them as having OpenCV is always a bonus.

sudo apt-get install libilmbase-dev libopenexr-dev libgstreamer1.0-dev libjasper-dev libwebp-dev libatlas-base-dev libavcodec-dev libavformat-dev libswscale-dev libqtgui4 libqt4-test

If this gives you an error because you do not have the libqtgui4 packages installed, retype the line, but without the last two packages. It should work now.

Now you’ll need to set up the Virtual Environment.

python3 -m virtualenv -p python3 env --system-site-packages 
echo "source env/bin/activate" >> ~/.bashrc 
source ~/.bashrc

The meaning of the second line: in the bashrc file,.which is located in the home directory, concatenate (add to the end) the text written in double quotation marks. > means overwrite. We don’t want to use this because we don’t want to overwrite an important file with a lot of bash shortcuts. On the other hand, >> means concatenate, which means add to the end of the file. The meaning of the third line: the bashrc file runs every time you open a new tab of Terminal. What if you want to reload the bashrc file, because of the changes made using the second line, in the same tab? You use source. You’ll note that the bashrc file has the line of text we concatenated at the very bottom (refer to image).

Now, the DonkeyCar Python code needs to be installed. Please cd to the Projects directory we created earlier and then install the code from GitHub.

git clone https://github.com/autorope/donkeycar
cd donkeycar
git checkout main
pip install -e .[pi]
pip install https://github.com/lhelontra/tensorflow-on-arm/releases/download/v2.2.0/tensorflow-2.2.0-cp37-none-linux_armv7l.whl

Although optional, you can install OpenCV. You should definitely install the library if you installed its dependencies earlier.

sudo apt install python3-opencv

You can test to see if the import was a success by entering:

python -c "import cv2"

Step 6: Create Your DonkeyCar Application