Piloting a seven-segment board with gestures

Small video demo (with the ux as of 20/02/2024 - it will change): https://1drv.ms/a/s!AjMgPYDiHw6gqslRsRapyz2YUNRxWA?e=cCj1WB

Installation quick guide on raspberry pi 4 (4 Go)

Prerequisite

When creating the raspberry image with Raspberry Imager

• Choose Bookworm 64 bits to have cv2 and all the good things right
• If you want to test the display with alfazeta java 8 app, Choose OS / Other / Pi OS Lite (32-bit) prefere Bullsey over to have jdk 8 and test the board. And for this, user name should be pi. But you wont be able to launch the project which need more modern stuff for cv2 etc.
• In Settings make sure ssh is enabled, choose your regional settings, choose your wifi

Kind remember

• To activate VNC, ssh to your raspi and launch sudo raspi-config > 3. Interface Option > 2 VNC, Yes, Enter

Installation of the application on the Raspi

1. Activate Serial com: sudo raspi-config > 3. Interfaces > Serial > No to console on serial / yes to serial interface > save > reboot

2. Clone this repo or your own fork if you plan to adapt it (cf section To code remotely)

3. Check that picamera2 is installed with sudo apt install -y python3-picamera2

4. Create environment in the local repo directory, without forgetting to add --system-site-packages option to access to picamera2: cd <repo>; python3 -m venv .venv --system-site-packages

5. activate environment : source .venv/bin/activate

6. install requirements : pip install -r requirements.txt

7. launch calling bash start.sh! Stop with ctrl-C.

8. Don't forget to call bash stop.sh if you want to set dark mode before moving the physical display

Starting it when booting rapsi (and set dark mode when shutting down)

In repository folder

1. Adapt sevendots.service and start.sh to your path

2. sudo cp ./sevendots.service /etc/systemd/system/

3. sudo systemctl enable sevendots.service

To code remotely and push things back to github

1. If you have not yet configured ssh connection with public keys, add the public key to accept connections from vscode from your main computer. For this, execute on your main computer: ssh-copy-id -i ~/.ssh/<keyfile>.pub name@server.local

2. Use vscode live share

3. add (manualy) the private key to push on github, with chmod 600

4. set git name and email

git config --global user.name "Your Name"
git config --global user.email "email@domain.tld"

Testing serial

import serial
ser = serial.Serial(port='/dev/serial0', baudrate=57600)
# should answer True
ser.isOpen()
# should print Serial<id=0x........, open=True>(port='/dev/serial0', baudrate=57600, bytesize=8, parity='N', stopbits=1, timeout=None, xonxoff=False, rtscts=False, dsrdtr=False)
print(ser)
# should answer 32 and print "-" everywhere
ser.write(bytes([0x80, 0x83, 0x00]+[0b1]*28+[0x8F]))
# print all segments once on first line than "0123456789ABCDEF -?':" on the other lines
ser.write(b'\x80\x83\x00\x01\x02\x04\x08\x10\x20\x40\x7e\x30\x6d\x79\x33\x5b\x5f\x70\x7f\x7b\x77\x1f\x4e\x3d\x4f\x47\x00\x01\x64\x02\x09\x8F')

Troubleshooting

If when instantiating ser, you have FileNotFoundError: [Errno 2] No such file or directory: '/dev/serial0', be sure to have activated Serial in raspi-config (No to console on serial / yes to serial interface, cf 1.)

You can also try to access to the serial port with stty, for example:

stty -F /dev/serial0 speed 57600 cs8 -cstopb -parenb -echo
echo -en '\x80\x83\x00\x01\x02\x04\x08\x10\x20\x40\x7e\x30\x6d\x79\x33\x5b\x5f\x70\x7f\x7b\x77\x1f\x4e\x3d\x4f\x47\x00\x01\x64\x02\x09\x8F' > /dev/serial0

Special thanks

• To AlphaZeta for making this device
• To Ksawery Kirklewski for making this pretty and explaining how to do it
• To the nice people from the parisian maker shop LetMeKnow