The marker mini program runs great in the preloaded firmware. I did notice some room for improvement. Since the program starts with the front LED lights “on” they seem to put a significant glare on the marker cards making them harder for the camera/microcontroller to recognize.
To help you can tape tissue paper across the front with some tape to diffuse the light. Make sure not to cover the cameras view. This addition seems to keep the markers from getting visually blown out.
Another possibility is if they are connected to PWM pins we could reduce the brightness. Or just use the LED off as the first card and do not turn them back on, but what is the fun in that