Latest is that this is *almost* looking like working.
I noticed that one of the pallet pins is a bit loose (depicted in this clip) so that will need addressing. It is 0.5mm diameter.
After that I need to put a hairspring on the balance wheel, and then I may be able to get it to tick for the first time by applying torque to the escape wheel with my finger. ... https://www.youtube.com/watch?v=RLNDavSXPrc
Just a first test of SCAMP connected up to a VGA monitor and USB keyboard via the RC2014 serial terminal.
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https://www.youtube.com/watch?v=SeqtUNc7O7s
Today went really well, part 1 didn't take *too* long to do and the delta time for part 2 was better than I thought possible on SCAMP, especially when you consider how long it takes to re-download the input.
No video yesterday because it was too hard, you can read my notes here: https://github.com/jes/aoc2021/tree/master/day5
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https://www.youtube.com/watch?v=LrLMMJRUvV4
This is just for data to help with validating my simulator: https://incoherency.co.uk/oscillating-engine/
You could use it for the same purpose if you like. Apart from that, it's not very entertaining.
In case it helps:
My Wig-Wag is not built exactly to the drawings. The bore is 15.2 mm (+0.2mm vs spec), the length from the crank pin to the top of the piston is 61mm (-2mm vs spec), and the gap above piston at top dead centre is 8mm (+3.25mm vs spec, I am as confused as you about where the extra 1.25mm has come from).
Also both the pivot rod and the crankshaft are a bit loose in their bearings, hence the knocking sound, and there is a bit of leakage at the port face. A well-built engine would run better.
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https://www.youtube.com/watch?v=8nPL7HZbTow
I'm working on a program to wrap flat meshes into cylinders, for the purpose of creating the interior parts of a puzzle that is too annoying to model as a cylinder. https://github.com/jes/stlwrap
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https://www.youtube.com/watch?v=h6RayUmmZ9M
Now with the driver seated behind the wheel, steering by moving the hands instead of with the joystick, a slightly larger track layout, and better framerate.
Based on https://github.com/BastiaanOlij/vehicle-demo
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https://www.youtube.com/watch?v=20ie-DFDp3M
Built from plans at https://wigwagengine.wixsite.com/wigwag
I was too hasty in trying to run it while the port faces were misaligned, and I've done some damage there, but it does run.
Once I've made those faces mate properly I can move on to hooking up the pressure sensor and some form of crank position sensor and compare the pressure-volume diagrams to the simulation.
The simulation is: https://incoherency.co.uk/oscillating-engine/
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https://www.youtube.com/watch?v=dAE3zGb_kEw
Z probe using Grbl. The plug is an audio jack in a 3d-printed housing. Then one lead is alligator clipped onto the tool, and the other lead is plugged into a piece of stainless steel that I turned on the lathe. The stainless steel is 24.68mm long, so we know that when the tool touches the stainless steel, it is 24.68mm above whatever the stainless steel is on, so it then knows the Z height offset.
The wires are a bit stiff, I should replace them with something more flexible.
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https://www.youtube.com/watch?v=1wm8HoF5RQ8
Now with engine torque curve and gear ratios modelled off data I could find for real Caterhams (although the engine and gearbox come from different models!) along with a super basic sound model. It's a single looped sample with frequency adjusted based on engine RPM and amplitude adjusted based on throttle position. I agree it sounds a bit tappety.
I don't know what is causing the glitchy grey rectangle that appears at the end.
Based on https://github.com/BastiaanOlij/vehicle-demo
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https://www.youtube.com/watch?v=cXUsfVIx73c