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how to work with this

good day guys.. do you have any ideas of using tachometer of an inkjet printer in reading rpm's? i want to use this one for reading rpm's using arduino..thank you very much.






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Inside the black plastic thing is an IR LED and IR sensor pointing at each other. As each black stripe on that plastic disc comes around, it breaks this IR beam and is thus counted.

Your googles are:

  • Arduino encoder
  • Arduino Slot encoder
  • Slot Interrupter

Your code will be pretty simple, when the device is triggered, start a timer (remTime=millis()). Then, when the next stripe comes around and you get another "click" from the encoder, stop the timer and subtract. From there, it is simply doing the math on total number of stripes/ time elapsed for one stripe/ etc.

thank you so much.. first.i didnt know the name of that device.. thanks to you that you said it is a  Slot Interrupter..

but i wonder the pins.. the pictures 1 to 3 has 6 pins..while the other with the dc motor has 5...or that 6 pins is not a slot interrupter?

but..thank you very much for the help.

You are going to need to do some experiementing. You need to do some continuity tests. You will need a multitester (meter) or even just a battery, resistor and LED. All you need is something to blink or beep when connected.

You will use this little tester to simply see what is connected on the board. Touch one probe to a motor connection, then find that same connection at the connector --or anywhere else for that matter, you are simply looking for somewhere you can "tie-in" a connection. I.e. where is the easiest place you can solder and/or connect a couple wires that eventually connect to your motor.

The encoder will be a bit more tricky, but you are looking for a few "findable" things. First, the LED side of the sensor will probably have a resistor in-line with it (in series). The other side of this resistor probably goes to + some where on the board. The sensor side probably has a resistor too, and it will also be connected to +, but it will also be broken out to your connector.

There is no good way of doing this, and there is no step-by-step system to do it. You need your meter, a notebook and pen and some time. You will get it.