Problem overlaying RGB and Thermal images


I am working with the OpenMV CAM RT, integrating that with the Lepton 3.5 thermal camera connected via SPI and I2C. I ran the example and I got this memory error.

What is the cause of this error and how can I solve it?

Hi, due to the use of ESD protection circuits on the I/O pins of the RT1062 I found that the FLIR Lepton doesn’t work when you talk to it via the boards SPI/I2C pins. I don’t have a fix for this. Basically, if the clock frequency is pushed to high bits become wrong. It’s not an issue for outputting data but it is an issue for reading data. Things work okay in the 8 MHz range and below but fail above that (FLIR Lepton 3.5 is 20 MHz). I think the FLIR Lepton 1 would still work. But, not the 3.5.

If you want to attach a FLIR Lepton via the I/O headers through SPI/I2C please use the H7 Plus. It works fine.

Does removing the ESD and using higher clock frequency works for the Lepton 3.5? Or it is totally circuit bound issue? Thanks!

I don’t see how you’d bypass it. The part is 4mmX2mm with 8 wires that are 3mil each running to it. This is beyond hand soldering generally.

I tried taking a snapshot and the output is a bit strange, quite difficult to understand, could it be because of the reason you mentioned earlier?


Yeah, as mentioned, the system can’t really receive the data correctly.

If you want to do this you need to use the H7 Plus.