[Motmot] soldering the AT90USB

[Andrew Straw]

(I'm forwarding this to the motmot email list, as it concerns the Motmot
CamTrig device, and the conversation might be useful to others
attempting to get one working.)

Paolo Segre wrote:
> Well, I got the ground (J5 pin 2) and the J5 pin 4 soldered in. It only
> took me two hours to try to clear the damned solder out of those two
> holes, and I'm pretty sure that I messed something up.

Yeah, the AT90USBKEY is a real pain to solder.

> I plug those two pins into the connector and the AT90USB key loses
> power.

OK, check for shorts between the various pins. Chances are that this is
the problem.

 Mainbrain is still able to find the trigger device so the key
> isn't completely fried, but I just can't figure out what's going on. The
> oscilloscope connected to the BNC output doesn't read anything.

If the board loses power due to being shorted in this condition, it
makes sense that there won't be a signal to see. Once you get beyond the
short circuit debugging, you can test the functionality of the camera
sync trigger using the fview_ext_trig command-line command::

  trigger_set_frequency --freq 200

where 200 would be the frequency (in Hz) that you want to trigger the
cameras. I've just added a tiny bit of documentation about this to
http://code.astraw.com/projects/motmot/motmot.fview_ext_trig.html#command-line-commands

Also, you can always use the --help argument to any of the commands and
get usage information.

I hope that helps,
-Andrew

-- 
Andrew D. Straw, Ph.D.
California Institute of Technology
http://www.its.caltech.edu/~astraw/