02GF74
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| posted on 1/11/06 at 03:17 PM |
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small 12 V DC motor
I am looking for a 12 V DC motor than can zoom up to about 3,000 rpm - it is to drive a car speedo. It will be driven from low rpm so has to be
respond well to low voltage (or do I pulse it?)
Not found anything suitable yeat (maplin/ebay/rs) - anyone know of one? (will look round model shops).
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Confused but excited.
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| posted on 1/11/06 at 04:27 PM |
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small 12v dc motor
12 v dc rechargeable drill motor?
Dead cheap s/hand as the drills are crap!
Tell them about the bent treacle edges!
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pewe
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| posted on 1/11/06 at 04:33 PM |
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Some people always want the obscure don't they? ... try www.parvalux.co.uk if they can't help they will probably know somene who can.
Cheers, Pewe
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Kissy
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| posted on 1/11/06 at 04:34 PM |
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Sounds like you need a stepper motor.
Either that or one out of a scalextric car!
Either way I can help. U2U me if I can help.
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PeterW
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| posted on 1/11/06 at 05:17 PM |
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Try Here
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paulf
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| posted on 1/11/06 at 11:06 PM |
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Ive also considered trying to build something like this to allow an electrical drive of a mechanical speedo.
I found some usable motors in my box of old printer and disk drive parts, the tray motor on a CD drive looks usable.i think it may need a feedback
system adding either a magnetic or optical encoder would do .There is a motor on the distel site that looks as if it may work and includes an encoder
but is a bit on the large side.
Most ford speedos are 1000 tpm so 1000rpm would be 60mph and therefore 3000 is more than adequate for a seven type application.
My idea is to use an analog system to give a voltage using a comparator type circuit and using the input pulses to give a variable input voltage.
Paul.
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Syd Bridge
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| posted on 2/11/06 at 10:28 AM |
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Would it not be far easier to just drve a stepper from a proper chip that runs off the pulse input?? Replace thew speedo guts with the stepper.
Or feed the pulses into a PIC, and output to a digi readout??
Far less complicated.
Cheers,
Syd 
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paulf
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| posted on 2/11/06 at 09:05 PM |
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That may be an easier solution , but my intention was to make an add on unit that people could use to modify any mechanical speedo to fit a different
engine gearbox combination . It would consist of a small servo motor that could be attached in place of the original cable and a sender and control
calibration box for the gearbox or propshaft, and would make it much easier to use different donor instruments.
Paul.
quote:
Originally posted by Syd Bridge
Would it not be far easier to just drve a stepper from a proper chip that runs off the pulse input?? Replace thew speedo guts with the stepper.
Or feed the pulses into a PIC, and output to a digi readout??
Far less complicated.
Cheers,
Syd
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G.Man
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| posted on 3/11/06 at 06:19 AM |
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most model shops can provide 12v dc motors in either brushed, or preferably brushless configuration...
One sorce of small brushless motors is also CD-Rom drives that you no longer use...
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
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02GF74
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| posted on 3/11/06 at 02:14 PM |
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got a motor from maplins; not man enough to turn the speedo  , so £ 5 badly spent.
Also got a stepper - boy do they have some torque
not sure it can go at those sort of speeds I need (my calculation is somewhere between 2 and 3 000 rpm; it is not a Ford speedo). maybe I can drive
it that fast or else may need a couple of gears.
all the bits of money spent makes me wonder whether to splash out on a new one ... but will look on ebay onece in a while.
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02GF74
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| posted on 3/11/06 at 02:22 PM |
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quote:
Originally posted by Syd Bridge
Would it not be far easier to just drve a stepper from a proper chip that runs off the pulse input?? Replace thew speedo guts with the stepper.
Or feed the pulses into a PIC, and output to a digi readout??
hmm. gut the intrernals and fit a LCD mileometer hmmm....; didn't consider that.
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