Calibrate

Your camera’s shutter keeps turning in front of the sensor. If the sensor’s timing doesn’t match the motor, a dark band rolls through the picture. Dials are rough: a Nizo set to 18 runs at 17.2.

Run it

1. Load the cartridge, set the dial to the speed you film at, and aim at a plain, evenly lit wall.
2. On the Pi, stop the recorder and start the calibration with your dial speed:

sudo systemctl stop s8cam.service
python3 ~/s8test.py --calibrate --dial 18

3. When it asks, run the camera for about 13 seconds. Measuring starts by itself.
4. Start the recorder again: sudo systemctl start s8cam.service.

It reads the motor speed from the shutter band and writes it into s8profile.json. Use more than one dial speed? Calibrate each, then pick the one you film at under Settings on http://s8cam.local:8080.

The rule

The exposure is exactly one motor cycle, so every row of the sensor sees one full turn of the shutter and the band disappears.

exposure_us = round(1,000,000 / motor_fps)
FPS         = 1,000,000 / (exposure_us + 800)

The 800 µs is the sensor’s gap between frames. ?

Know your motor speed already? Type it into the Builder’s Motor speed field and download a new profile.