Picar-x with RPI5, camera too dark

Hi all

I was building the Picar-x-v20 using a Raspberry Pi 4, and all was working great until I wanted to start using more demanding modules like Visison Ai stuff, etc.

So I got hold of a Raspberry Pi 5 with 8GB RAM, and a fan HAT to sit between the RPI5 and the SF Robot HAT. Again, all seems to be working fine BUT the output form the camera is VERY dark compared to when using it with the RPI4.

Is anyone else having this problem or can advise how to improve the lighting in the video?