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Show HN: A coilgun I built when I was 16

3 points| wgbowley | 9 months ago |github.com

I made it when I was 15 or 16, so it's nothing amazing—just thought I'd share

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perilunar|9 months ago

Cool. I've always wanted to build one. How did you determine the coil sizes, voltages, timing, etc.? Lots of calculations, or just TLAR method?

wgbowley|9 months ago

For the coil and yoke, I definitely used the TLAR method (though I did run it through FEMM to see if it would work). For voltage, I just went with the biggest supply I had, and for timing, I simply used a program that estimated the extra time needed after the projectile passed the photo-gate.

Keep in mind, I wasn’t very experienced at the time. If I were doing it now, I’d use a random search algorithm to find a coil design that generates the highest force while still switching quickly. For the power supply, I’d use a capacitor bank, and probably stick with similar timing — or possibly use a dedicated capacitor for each stage, charging each differently to deliver longer or shorter pulses as needed