LED matrix flickering on picture/video


I bought a couple of Adafruit Mini 0.7" 8x8 LED Matrix w/I2C Backpack – Pimoroni and they work fine BUT when I try to take a picture or a video it seems I can’t have all the LEDs displayed. Seems like a very slow multiplexing (but fast enough for the eye).

Here’s a picture of one led matrix with every pixel ON.


I’m using a Pi Zero and Python (but tried a C implementation and it was the same).

Is this due to the HT16K33 driver ? (but I saw video of LED matrix with this driver that were not flickering).

Thanks a lot !


ALL multi-LED displays use multiplexing to operate the LED segments both to reduce power requirements and, principally, to reduce the necessary pin count of the display array.
There is no standard scanning frequency - it’s just set so the eyes cannot see the flickering effect but, as you’ve noticed, a (video) camera usually has such a short shutter time you only see some of the segments lit.
Using a still camera you can get all the segments lit if you can slow the shutter speed right down.

Thanks a lot neilman !