the Thomas Winder

[David Schwab]

Yeah, I use that same foam tape on Fender pickups. On humbucker bobbins I can get away with standard double sided tape. The Fender type pickups need something that fits the irregular surface for the strongest bond.

For Fender pickups I have a piece of wood drilled out for the magnets and with a center hole for a screw.

[RedHouse]

I've built such a beast and it does work. Bobbin position is sensed by an Agilent optical encoder that generates a pulse per rotation in one channel and 500 pulses per rotation in two other channels (in-phase and quadrature), so one can determine axle angle to a bit less than a degree of angle.

But a LED isn't nearly bright enough when making short-enough flashes, so I built a homebrew xenon strobe light. Even so, one needs to dim the room to not wash the light from the strobe out.

I recall someone here telling me it wouldn't work when I had this very same idea some years ago, something about the LED not fast enough or whatever.
(been working fine for me ever since I was told it wouldn't, but never mind)

[Joe Gwinn]

I recall someone here telling me it wouldn't work when I had this very same idea some years ago, something about the LED not fast enough or whatever.
(been working fine for me ever since I was told it wouldn't, but never mind)

Probably was me. The issue is how much blurring one will accept at the highest winding speed. I wanted zero blurring at 1200 rpm, because the higher the speed the greater the need to see, to debug the winding process enough to allow reliable high-speed winding. I investigated LEDs, but they were too slow and thus too dim at max speed.

I suppose LEDs have gotten better, but I doubt that they can match a small xenon flash for intense few microsecond flashes.

The circuit of a xenon flash is pretty simple, and has not changed much since the days of Doc Edgerton: Flashtube - Wikipedia

The only modernity allowed was the use of SCRs for triggering and optical couplers to get the Fire! command from the CMOS logic domain (low power, low voltage) to the strobe domain (high power, high voltage). (The traditional approach, trigger transformers, didn't work because too much power backfed from strobe to logic when the strobe fired, confusing the logic. With optical couplers, there is no such backfeed.)

Do you have any way to measure the duration of your LED flashes? This would be the optical duration, not just the electrical drive duration.

[RedHouse]

Probably was me.

Yeah it was ...but I was just elbowing ya in yer rib there.

For me it's not really a "freeze-frame" thing I was after but more of a "highlighting" effect which doesn't need a xenon flash IMHO.

After all a normal desk lamp works fine to see where the wire is lying, and each time the bobbin rotates it kinda flashes, but back when we had the discussion before I was actually wanting something just to blink (in sync) with each turn of the axle and let my persistance of vision do the rest.

[Joe Gwinn]

After all a normal desk lamp works fine to see where the wire is lying, and each time the bobbin rotates it kinda flashes, but back when we had the discussion before I was actually wanting something just to blink (in sync) with each turn of the axle and let my persistence of vision do the rest.

Ahh. A LED can do this. What color is the LED light? (White is the slowest because of the phosphor layer that converts blue to white.)


I wanted to freeze motion so I could see why I was getting for instance loose loops (turned out to be the wire catching on the bobbin flange for an instant), and the faster one goes the more such things happen.

[David Schwab]

Joe, around the time of your birth, were your parents part of any covert government experiments that you are aware of?

Not to my knowledge, but then when I was at age ~ zero how would I know?

Eh hem. Not counting this I suppose? Looks like a secret weapon to me.

[RedHouse]

THAT's our Joe!!!!!!