FLIR Lepton 3.5 on long cable

[Daniel Wirch]

I am using a Lepton 3.5 on a breakout board V2 nad its connected to a rpi4. 

When I am running the capture code from pylepton it is working fine, aslong as its connected via jumper cables over a short distance. Once I coennect them both with a 2m D-Sub 25 it makes weird noises and the shutter opens and closes every one or two seconds. The sound is happening while the shutter is closed. When i rund the command it returns some lines with "garbage frame number resetting..." and after some time it processed the frame, but its corrupted. just white and black lines and the temperature values are all over the place between -273.15°C and +390°C.

[Flir Lepton]

Hi Daniel,

The breakout boards use 20MHz SPI for communication with the host. 

This protocol isn't suitable for cables longer than ~15cm.

If you're looking for an off the shelf solution, I recommend using a USB PureThermal board since USB is much better over long cables.

GroupGets - Griffin