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From: Rich the Cynic on 29 Jul 2010 21:30 On Wed, 28 Jul 2010 16:36:00 +0100, markp wrote: > >> John "The Bloviator" Larkin's post is a slap-it-on-paper-quick without >> thinking "solution". Use at your peril. He'll never label it with >> values. If he did, his "solution" could be checked. > > I rest my case. I guess he has to go after John since he's plonked practically everyone else on the group, presumably to "punish" us. (Ha, ha, I can't hear you, nanner nanner nanner!) ;-) Cheers! Rich
From: Rich Grise on 29 Jul 2010 21:37 On Wed, 28 Jul 2010 11:09:17 +0000, Jan Panteltje wrote: > On a sunny day (Tue, 27 Jul 2010 18:30:29 -0700 (PDT)) it happened Dookie > <abstract.dissonance(a)gmail.com> wrote in >> >>I know there are a god awefull number of ways to do this but something >>simple with minimum and common parts is what I'm looking for. > > I still have some LED-photodiode packages that look one way, put a > reflective strip on the flywheel. I dunno what these things are called in > Engish really, but I am sure you can still buy those : > --------------- > | LED ---------> | > | | | > | Photo diode <--------- | reflective strip > |_______________| Reflective opto sensor, or almost anything conveying the same idea. BTW, this was also my suggestion, but you beat me to it. ;-) Cheers! Rich
From: Rich Grise on 29 Jul 2010 21:38 On Wed, 28 Jul 2010 13:43:18 +0100, markp wrote: >> Dookie <abstract.dissonance(a)gmail.com> wrote in >>>I know there are a god awefull number of ways to do this but something >>>simple with minimum and common parts is what I'm looking for. >> >> I still have some LED-photodiode packages that look one way, put a >> reflective strip on the flywheel. I dunno what these things are called >> in Engish really, but I am sure you can still buy those : >> --------------- >> | LED ---------> | >> | | | >> | Photo diode <--------- | reflective strip >> |_______________| >> > Another possibility, if you can afford to put a small paddle on the rim, > is to use a slot sensor (these have an infrared emitter in one side and a > receiver in the other). Optical interruptor. ;-) Cheers! Rich
From: Rich Grise on 29 Jul 2010 21:43 On Tue, 27 Jul 2010 18:30:29 -0700, Dookie wrote: > sinusoid damped(or alternatively the derivative of the erf function). I > have about 200-300 turns and the coil is getting unwieldy. Then maybe magnetic isn't the way to go right now. I'd suggest more like 2000-3000 turns, of very fine wire - Or, just use a white stripe and a reflective optical sensor; it won't matter how fast the shaft is going: http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=1967257&k=opto%20sensor http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=1967052&k=opto%20sensor Good Luck! Rich
From: John Larkin on 29 Jul 2010 23:06
On Thu, 29 Jul 2010 18:30:04 -0700, Rich the Cynic <cynic(a)example.net> wrote: >On Wed, 28 Jul 2010 16:36:00 +0100, markp wrote: >> >>> John "The Bloviator" Larkin's post is a slap-it-on-paper-quick without >>> thinking "solution". Use at your peril. He'll never label it with >>> values. If he did, his "solution" could be checked. >> >> I rest my case. > >I guess he has to go after John since he's plonked practically everyone >else on the group, presumably to "punish" us. (Ha, ha, I can't hear you, >nanner nanner nanner!) ;-) > Right. He only distributes technical excellence now in private emails, because we village idiots don't deserve such wisdom. Darn, I was hoping for further adventures in rusty patio furniture. John |