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Topic: Can this DC motor w/encoder be reused? (Read 1 time) previous topic - next topic

Dec 29, 2011, 04:40 pm Last Edit: Dec 29, 2011, 04:44 pm by hugo_rosario Reason: 1
Hello everyone, I am new to arduino and I started harvesting some parts from old devices I had around here.
I harvested a cool DC motor from an old multifunction printer which has an optical encoder attached and would like to have some help with the wiring.

How can I find out which pin is Vcc or GND and which are the output of the encoder and how do I read it?
There are 6 pins on the connector.

See pictures attached...

Thank you all...
Arduino is a really cool project. Love it.

johnwasser

You can often figure out which pin is which by tracing the lines on the circuit board.  I expect two of the pins will go to the motor, two will go to the LED in the optical interrupter, and two will go to the light sensor (phototransistor) in the optical interrupter.  You will need a high current source to drive the motor.  An NPN transistor will do if you only want the motor to go in one direction.  Use an H-bridge chip to go in either direction.  The LED can probably be hooked to 5v but it might need a resistor to limit the current.  The sensor can probably go between an input pin and ground.  Turn on the internal pull-up resistor for the input pin.
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robtillaart

do you have a picture from the bottom / circuitry?
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
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#3
Dec 29, 2011, 07:19 pm Last Edit: Dec 29, 2011, 07:21 pm by hugo_rosario Reason: 1
Thank you johnwasser, really looking at the circuit board I identified a few things :

- Pin 1 and 2 go directly to the motor, I will use a TIP121 transistor and an external power source.
- The Emitter has 2 connections, there is a resistor between pin3 and the Emitter, so its the Vcc, the other is connected to pin4, which is GND.
- The Sensor has 3 connections : one is going to pin4 (GND), the other is connected to Pin5 and the other is connected to Pin6 and Pin3 (this one got me confused)

Check the circuit on the picture below.


johnwasser

Looks to me like there are probably two optical sensors for quadrature output.  That will allow you to detect direction of motion.

Pins 5 and 6 are the quadrature outputs with pull-up resistors.

Try +5 on 3 and ground 4 to turn on the LED.  Then use 5 and 6 to detect motion.
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Hi again, hope you all had a good new year´s eve.

I am back to attempting to read the optical sensors and I dont get it. I connected the 5 and 6 pins to the arduino analog inputs and I dont get any different values, its the always the same output, when the motor is either running or stopped.
Pin6 is always HIGH (1023 in Analog) and Pin5 is always different (which is what happens when you read a pin that is not connected to anything).

Maybe I damaged something when I soldered the wires on the board...

Thanks for your help anyway, the positive side here is that I learned a little bit more about motors and optical encoders.
You guys rock...

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