| jonas | Posted: 27 Jun 2025, 12:21 PM |
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 Member Posts: 7 Joined: 29-May 25 |
Hi there, finally managed to get my IV kit from the customs and immediately assembled it. I have two questions – when set to "toggle mode" I noticed that the timing of the colons is not very precise on the mkII1/2 when compared to mkIV. Or at least it "seems" that way: https://www.dropbox.com/t/uwLZLV8BJ1p4KVEv Is this expected? Second question – I lost the cable protecting acetate cutout somewhere, is there a way to get a dxf or svg file so I can cut out my own? (I have a laser cutter available) Thanks for doing these, love 'em! ------------- |
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| mit | Posted: 27 Jun 2025, 03:05 PM |
 yeah whatever Admin Posts: 621 Joined: 4-May 16 |
The Mk III uses the colons to indicate debug data about the oscillator discipline. I originally did this in order to monitor/develop the firmware, but ended up leaving it in. Depending on if the oscillator is fast or slow, it adds a 100ms delay to the colon blink. The loop can take a while to lock, so it's nice to be able to look at the clock and see that it's alternating fast and slow, which means it's locked. When it first gets a fix, it might stay fast or slow for a minute or so before aligning. The Mk IV just has an animation, which I've arbitrarily aligned to the second, no debug data. But the onboard TCXO means there's no need to discipline the main oscillator. It does perform a slow calibration of the RTC though, for when the clock is turned off, and there's a debug mode than can show some info about it, but the RTC crystal is temperature sensitive so it'll never keep time that well. Laser-cut files are in the repo, but unfortunately they're in moshidraw format. One of my tasks is to convert or re-draw them in a sensible format, I'll get round to that soon. ------------- |
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| mit | Posted: 29 Jun 2025, 05:07 PM |
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yeah whatever Admin Posts: 621 Joined: 4-May 16 |
I've created an SVG version of the laser cutter files and stuck it in the repo: https://raw.githubusercontent.com/mitxela/clock4/refs/heads/master/cad/hinge.svg Moshidraw has this terrible habit of converting arcs into polylines which makes it hard to know exactly what the original radius and centre were, so the redrawn version of the acetate might not match exactly, but it should be close enough to work. For laser cutting acetate the best technique is to sandwich it between two pieces of soaking wet paper. This stops the edges from fraying and turning brown. ------------- |
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| jonas | Posted: 30 Jun 2025, 09:33 AM |
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Member Posts: 7 Joined: 29-May 25 |
Thank you very much for the help! I spent like an hour trying to find that piece. I am sure it was in the kit, but I just lost it somewhere. Is there a way to make the blink on MKIII regular? I am planning to use it in an art installation. Thanks again! ------------- |
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