how to convert from rotation of dc motor to output voltage

[izzul]

how can I change the rotation of the dc motor to the voltage? for example, when the dc motor is connected to the light, the light will light up. so my question, how can I get the output voltage on screen when dc motor rotates.?

 

[Tesla]

how can I change the rotation of the dc motor to the voltage? for example, when the dc motor is connected to the light, the light will light up. so my question, how can I get the output voltage on screen when dc motor rotates.?

Sounds like you are using a motor "backwards" and it becomes a generator. I think this only works with brushed motors.

To monitor the voltage going to the light, wire a meter or DC gauge in parallel to the light.