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counter / position circuit

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matty

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I want to build a counter/display that will count and display the position of the teeth of a rotor as it go's around from 1 to 36 then back to 1 etc etc, this will be triggerd by some sort of pick up on a 36 toothed gear / rotor.

Anyone got any ideas ??

Matt.
 

MikeMl

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If you want up down counting, you need to mount TWO stationary sensors near the toothed wheel. They could be Magnetic or optical. The sensors need to be mounted so as to have their outputs 90degrees out of phase (i.e. overlapping). This is called "quadrature" (Google it). A quadrature decoder produces two outputs: Count and Direction.

If you want only unidirectional counting, then use only a single sensor.

Connect the sensor(s) to binary or decimal counter i.c. chips. If you want a roll-overs at zero and 35, you will have to add decoding logic at the counter outputs. If you want a display, use decimal counting, 4line to 7segment decoders and Led seven-seg displays for the readout.
 
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ericgibbs

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Can i buy anything of the shelf to do this ?
There is this type of counter, they are not cheap and for only a two digit count an overkill.

What exactly is this rotor doing that you need to count the teeth.:)

Electronic Counters
 

matty

New Member
I have built an electric turn table, it turns 10 degrees at a time at the press of a button ( forwards or backwards ). I need to display at which position the turn table is at, ie 1 through to 36.
 

ericgibbs

Well-Known Member
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I have built an electric turn table, it turns 10 degrees at a time at the press of a button ( forwards or backwards ). I need to display at which position the turn table is at, ie 1 through to 36.
hi,
I see. Is this for a model railway.?

The cheapest way is to build your own electronic circuit.
You can buy rotary encoders from eBay that will give a pulse coded output.

Do you have the tools to build a simple counter.?
 
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