Re: [flir-lepton] Digest for flir-lepton@googlegroups.com - 1 update in 1 topic

[Dan Julio]

Daniel,

You are probably seeing two problems.

1. SPI bus interfaces aren't really designed for such long distances because of the high data rate.  It seems like you're seeing data corruption. You might be able to fix this with either a series or parallel terminating resistor.  You'd probably have to put a scope on the SCLK and MISO lines to tune the resistor value.  But probably you should find a way to shorten the connections.

2. You're also probably seeing a voltage drop which crashes the Lepton when it performs a FFC due to the inductive component of the long power lines.  You might be able to fix this with a large-ish electrolytic capacitor connected to the breakout board.  Something like 220-470 uF.

Ideally you wouldn't have a long connection between the module and the computer.  If you must then you might consider moving over to one of Group Get's UVC USB Camera modules since they can run up to a few meters from the computer, but of course the software would end up being completely different.

Hope this helps.

Regards, Dan

On Thu, Feb 15, 2024 at 7:02 AM <flir-...@googlegroups.com> wrote:

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• FLIR Lepton 3.5 on long cable - 1 Update

FLIR Lepton 3.5 on long cable

Daniel Wirch <daniel...@gmail.com>: Feb 14 06:42AM -0800 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.

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