#garfield Logs

Dec 09 2021

06:46 AM polprog: wont we all
09:31 AM rue_mohr: how do I draw a box in gimp?
12:45 PM Tom_L: https://superuser.com/questions/167873/how-do-i-draw-a-box-in-gimp
12:46 PM Tom_L: https://docs.gimp.org/2.10/en/gimp-using-rectangular.html
07:12 PM rue_mohr: hah
07:12 PM rue_mohr: thanks
07:12 PM rue_mohr: battery holder test first?
07:12 PM Tom_L: but why?
07:24 PM rue_mohr: its that or state machine software
07:24 PM rue_mohr: try to stay awake
07:27 PM Tom_L: no, why use gimp to draw?
07:27 PM rue_mohr: I was drawing on a picture
07:29 PM rue_mohr: cant get my mind to stay on track
07:29 PM rue_mohr: too much junk rolling around from work
07:30 PM Tom_L: leave work at work
07:30 PM Tom_L: unless you own the company it's not your problem
08:05 PM aandrew: Tom_L> leave work at work
08:05 PM aandrew: I've never ever been able to do that
08:06 PM aandrew: now that I work for myself it's less of an issue because at least I'm paid for it
10:04 PM rue_mohr: aandrew, ok, I got the holder good enough
10:04 PM rue_mohr: to be cheaky, I built a 1 transistor boost converter to show it off
10:10 PM miss0r: rue_mohr: I ended up calling it quits with the mosfet driver system. It seemed no matter what I did I could not make them survive sadly. even adding a 100mohm induction free resistor in series with the TVS diode across the mosfet did not do what I needed. Anyway - I ended up going for an SCR drive, which all but eliminates the flyback, because, well - theres no current at the point of turning off the SCR. So,
10:10 PM miss0r: as I've failed to do a proper job of the 50volt mosfet system I've opted for the 400volt scr system. Can you recommend a good way/type of charger to take 14.4 volts from a battery and ramp it up in a fast 400volt charger?
10:26 PM rue_mohr: definitly flyback
10:27 PM rue_mohr: you know 400vdc kills you in less than a heartbeat, right?
10:30 PM Tom_L: does DC hit harder than AC?
10:31 PM aandrew: it doesn't hit harder, but it doesn't let go is the problem
10:31 PM rue_mohr: it toggles the heart off
10:31 PM rue_mohr: you need another one to toggle it back on
10:31 PM rue_mohr: if the circuits aren't burned out
10:43 PM miss0r: rue_mohr: 10 years as an industrial electrician has tought me a thing or two about not getting killed by electricity
10:44 PM miss0r: flyback - no transformer?
10:46 PM rue_mohr: things still happen
10:47 PM rue_mohr: miss0r, transformers have too much magnetization energy
10:47 PM rue_mohr: how long are you trying to charge in?
10:47 PM miss0r: no doubt, it was just to say that I am not completely clueless, so anything blowing up in my face, is because I was asleep behind the wheel, not because you told me something dangerous ;)
10:48 PM rue_mohr: flyback
10:49 PM rue_mohr: oscillator, driver inductor diode
10:49 PM miss0r: Can I get any meaningfull charging power out of such a unit? :)
10:49 PM rue_mohr: yes
10:49 PM miss0r: Great :)
10:49 PM * miss0r is googeling
10:50 PM rue_mohr: got a VFD smoothing inductor?
10:50 PM miss0r: sadly no, but I bet I could get one
10:55 PM miss0r: even if I can't, i'm not one for backind down from a coil winding challange :)
11:03 PM miss0r: rue_mohr: Something along these lines: https://320volt.com/en/basit-mosfetli-flyback-surucu-devresi/
11:22 PM miss0r: I also found some problems with my chronograph on the coilgun, apparently when I cross ~25m/s of speed, the math goes haywaire in the arduino(something is happending atleast) so that it indicates that the projectile is moving at 80+ m/s (which it is clearly not) :D
11:23 PM miss0r: as that would mean I have an effeciency of over 12%, which is ludicris
11:56 PM rue_mohr: no thats a pushpull
11:57 PM rue_mohr: https://components101.com/sites/default/files/components/Boost-Converter.png