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Jitter

A project log for open-hardware transparent polygon scanner

laser scanner which uses transparent instead of reflective polygon

HexastormHexastorm 01/17/2019 at 17:320 Comments

Checked the jitter today and it is pretty bad. The facets do not overlay each other in time.
With the current settings the pru measures a 1 percent error in time. I have been able to work with a 0.25 percent and a 0.16 percent variance in the current setup, see the constant JITTER_ALLOW in the header. However after gluing I couldn't get it back to 0.16 percent. Probably the photodiode is not hit in its sweet spot.
Below is what I hoped to measure;  a nice series of dots.... The most upper dot originates from edge detection. This picture was made of a single facet.

The following picture was taken for multiple facets over a longer time.  I believe to think I can see four facets.  I can see two lines and two facets on that line.  As you can see from above there are no longer 3 dots but 6 dots in a line.

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