Rotation Counter

Hi all, I was wondering how I make a simple rotation counter for a modified servo. --kit

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What you probably want is a rotary encoder (shaft encoder). These are readily available devices, or you can make your own out of slotted disks and photo-diode/transistor pairs. Either way, the support circuitry is rather simple.
These pages might get you started: http://www.faqs.org/docs/electric/Digital/DIGI_11.html http://ww1.microchip.com/downloads/en/AppNotes/00718a.pdf http://www.interq.or.jp/japan/se-inoue/e_ckt10_3.htm http://www.circuitcellar.com/library/print/0303/millier152/index.htm
If all you need is a count of revolutions, then a single slot would be all you need. Another technique is to put a cam on the shaft and position a roller microswitch to register the revolutions.
Hope that helps, Daniel
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Hi,
Have a look at the inards of an old mouse (the ones with a ball), I've used one for a simple rotation counter.
Regards Ian Dobson
Home of the Atmel based UDP mobile web cam http://www.planet-ian.com All mails scanned with av-filter.pl (F-Prot / perl)

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Hi, I went the microswitch route since I had one hanging around. I just screwed a screw into the shaft then glued on a switch. So now I have a reliable rotation counter. Thanks for all the Ideas --Kit
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"kitmor"

Just keep in mind that with the microswitch you have no means to know which direction you're rotating, which could be fine for a myriad of applications.
Padu
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kitmor wrote:

using the encoders from an old ball mouse...or any sort of beam break sensor and a slotted wheel on the shaft
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