# SnailScanToo or 2

**URL:** <https://forums.kinograph.cc/t/snailscantoo-or-2/2548>\
**Category:** Machine Design\
**Created:** [June 8, 2023, 9:51am UTC](https://forums.kinograph.cc/t/snailscantoo-or-2/2548 "2023-06-08T09:51:59Z")\
**Posts on this page:** 1\
**Showing post:** 29

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**Author:** ![PM490](https://forums.kinograph.cc/user_avatar/forums.kinograph.cc/pm490/32/3176_2.png) [@PM490](https://forums.kinograph.cc/u/PM490)\
**Post date:** [August 21, 2023, 5:43am UTC](https://forums.kinograph.cc/t/snailscantoo-or-2/2548/29 "2023-08-21T05:43:55Z")

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This is a rough capture, but first one where all the pieces are linked.  
The Pico is connected via USB serial to the Raspberry Pi, which controls the transport and led via serial commands.

[![](https://forums.kinograph.cc/uploads/default/original/2X/7/75aa81f15fd29981bae2271eb38b4c43df015bef.jpeg "200 Frame Test Sequence") ](https://www.youtube.com/watch?v=Qm5UJAQjtKY)

When testing single captures, the frame length was adjusted until it did not shift away after several frames. There seem to be a shift from one frame to the next, and as seen in the video, these appear to be cyclical over several frames.

I have to think about what is causing these, thinking of an issue with the transport, but there may be a contribution on the spacing of the perforations.

> [@Simple Super-8 Sprocket Registration](https://forums.kinograph.cc/t/simple-super-8-sprocket-registration/1683/2):
>
> A suggestion: Use the same registration method for vertical but use the outer edge of the film for horizontal. Take a look at the gap between your perf and your film frame - see how it weaves back and forth? This is because in Super 8 the perfs are stamped using a 5-perf stamper that is never perfectly in parallel with the film. So you get a kind of sawtooth pattern. If you use the perf in Super 8 for registration, your perf will be perfectly placed but the picture will weave back and forth in a consistent pattern. Not all films exhibit this as much as others but it’s been a “feature” of Super 8 since 1965.

This is 16mm from the 50s, so I wonder if the pattern of the shift has a contribution of uneven perforations… probably not the case, since the edge of the picture does not change.

PS. Forgot to mention that the 100:1 gear steppers were replaced for 14:1, providing a bit more speed while keeping the number of steps for the smaller frame (regular 8) to about 900 per frame.

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