Thoughtophone

EspDRO  uses the ESPs ADC to avoid needing a level converter to receive caliper data. This makes me think I could do even better using STM32 ADC and Chibios: efficiently reading several calipers at once. I got out the calipers I'd previously soldered wires too, and promptly managed to break the wires off one. There are several connectors on Thingiverse now. I think I better print one. I found the EspDRO link in this one .

I never did get around to upgrading my circular saw cross cut jig for thicker material. Anyway, I found a Youtube video describing how to make one out of wood that I'm pretty sure I could get right, because it allows you to build the miter bar separately, and has a pretty fool proof way of setting it square. It's in two parts. The first makes the frame: and the second shows you how to make the guides: The whole channel is fascinating . I can't find anything like the window frame extrusion used in the videos. That would give pretty ideal results given my height limit of 10mm, but I guess what I got to work last time will work again: I just won't be able to make it any longer than last time. There are loads of good ideas here. I can't figure out exactly what some of the parts are, but I think I can figure out some equivalents in all cases.

I bought a brush-less fan PFB1212UHE  for £14. It seemed like a good deal - I was mostly concerned with the air flow and static pressure. It would have been better to buy an AC fan, because I need a 60W 12V power supply to control it. That's going to double the price... At one point I also thought I was going to need a brushless motor controller, but it just runs on 12V, and has an output signal which is one pulse per revolution. I guess that makes variable speed control relatively easy. It really is a powerful fan! It weights 380g and can levitate a couple of millimetres off the desk.

I've been wondering what I might do to control air quality in my very small shed. It's 1.5x1.8x2.1M, or 5.7 cubic meters, or 200 cubic feet. If I was just going to buy something specifically for this purpose, this WEN air filtration system costs £112, and would suck all the air in my shed through it twice in a minute. It's not massive - 50x45x25cm, but it would help if it was smaller, and it's noise isolation requires it to be hung from the ceiling, which I can't do if I don't want to bang my head on it. Lots of people have posted on YouTube on how to make air filtration systems using box fans. They are generally scaled up compared to the WEN, rather than down. This video points out why using a box fan isn't that good an idea. It's a rather over-complicated solution though: you can just buy a plate fan that includes a baffle. I suppose it's great if you have a fan you don't want. This video is the only attempt to make something signifi