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Old 10-01-2013, 09:40 PM
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alistairsam
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Location: Box Hill North, Vic
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Quote:
Originally Posted by OzEclipse View Post
Auto guiders as already noted are voltage switching devices. They won't switch resistors. You can do it but you'd have to add some sort of intermediate relay, that switches in those high/low resistors. Simplest low tech method is probably an old fashioned solenoid type relay that physically opens and closes mechanical switches that replace the push buttons or if you want to retain some manual control, hook them up in parallel after verifying the circuit is as I describe of course.

Joe
I'd strongly advise against solenoids, not really required.
Hence my suggestion to use opto couplers as a digital switch. Easy and cost effective.

Or why not use a digital pot like this one
http://littlebirdelectronics.com/pro...entiometer-10k

Replacing the motors with steppers would be good but very expensive as the appropriate gearheads for steppers are not that cheap. I've been down that road. Then you have the problem of an accurate controller for the stepper. I'd say that's a lot more complex.

I'll draw up a circuit and post shortly

Cheers
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