I am a newbie to Arduino.

What I am going to do is to change my roll to roll printer to flatbed printer. Rather using print roller, I decided to move the bed from a stepper motor.I know how to run the stepper motor for specific distance using arduino.

So I need to cheat printer to think that its roller is working and media is going through it.But actually what I am going to do is to monitor the printer motor running or not from arduino input and if the printer motor is running stepper motor will turn or if motor stops stepper motor must stop.

What my problem is how can I read that the dc servo motor status? How would I need to wire arduino input to servo motor to get the status.

Please show me some light on this.Sorry if this is a newbie question.

Thank you.

  • Any particular servo? Commented Dec 11, 2014 at 5:39
  • @IgnacioVazquez-Abrams sorry for posting external link.servo motor like this aliexpress.com/item/…
    – vinu
    Commented Dec 11, 2014 at 5:54
  • Do you have the datasheet for it? Commented Dec 11, 2014 at 6:05
  • No I haven't.Can't we just check whether power comes or not?
    – vinu
    Commented Dec 11, 2014 at 6:53
  • 1
    This may not work very well. If it is an actual servo motor, it will run to close the error and achieve position, while your stepper just gets a "step". You might be able to detect each "pulse" of movement and advance a line, but the simplest solution would be to use that motor for your flatbed mechanism. If you can't do that, you could consider putting an encoder wheel on the motor and driving your stepper from those signals, either with some clever logic or a micro controller - effectively "electronic gearing" Commented May 11, 2015 at 23:21

2 Answers 2


Do you need to check if it is stalled? Or simply running?

Either way, you could check the voltage with an analogue input, compare against a threshold (empirically set) & use that. Take the voltage reading from the non-commoned side of the motor, after any driver circuit.

If you want stalled, a small resistance would help, if just running then you could get away with a digital input.

If the voltages aren't matched then a resistance divider chain would be necessary.

  • 1
    Thanks for the answer.No I just Need to check motor running or not.
    – vinu
    Commented Dec 12, 2014 at 3:45

I would definitely use an Opto-Isolator between the motor and the Arduino for these reasons.

You will have a problems with the grounds as the motor reverses. The 24V supply. If you get something slightly wrong then it will take out the Arduino and the PC connected to it. The motor will generate large voltage spikes( circa 50..300Volts) under certain condions. The Arduino and the PC connected to it will complain, but not for long!

  • Thanks alot for your answer.Since I am new to electronics I don't know how to connect those between arduino and motor.Can You explain it little bit deeper?
    – vinu
    Commented Dec 16, 2014 at 4:46
  • This would normally be handled with a series resistor and a diode clamp, potentially a bidirectional one. That lets the Arduino sit at the ground potential of the motor driver and determine direction by watching the two sides of the motor. Commented Nov 8, 2015 at 4:26

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