View Full Version : Connecting multiple motors to Arduino

02-21-2013, 09:50 PM
I am using two servo motors for my project. However motors draw considerable amount of power and so I think both cannot be connected to the 5V port on the Arduino. So I will supply 5V potential difference from external 5V eliminator. My question is how do I connect the servo motor to ground? If power is given from the positive terminal then the negative terminal should act as ground. But again if this is so then I think the microcontroller cannot control the motors. So I think that the black wire of the servo motor should be connected to the GND port on the Arduino. Am I right? Please anyone confirm my concept before I actually apply it.

Thanks in advance.

02-22-2013, 05:27 PM
Just make the grounds common. Connect the black wire to both the external supply's ground and arduino ground.

04-03-2013, 09:55 PM
Something like this...


02-05-2014, 09:00 PM
When ever you are using external power to power your device and controlling it with arduino, make the common ground. That is Arduino GND and the power supplies GND should be common and connect the same GND junction with the device you want to run.

02-07-2014, 11:48 AM
I don't get it..how are we supposed to connect the external supply?

02-13-2014, 05:39 PM
need simple suggestions .. anyone

02-14-2014, 09:00 PM
I can't confirm the authenticity of the two accounts that have been posting on almost every thread with headless one liners, so I will just respond to the last comment.

Thumb rule, if you have power supply and logic supply in any single system. Make sure that the grounds/references are common. The ground/reference helps maintain the controller's sanity in terms of understanding the obvious difference in voltages of the logic and power systems for the transistors to work properly.