2

Let's say I want to control two servos from my Raspberry PI but I want to give them the exact same movements.

Could I connect them to the same GPIO port, so they can use the same signal? If not, what is the easiest (and maybe cheapest) way to achieve that?

4

I don't see why not. Why not try and see?

You only connect the control wire to a GPIO.

The current is negligible.

Personally I always connect the control wire direct to a GPIO for a servo.

If you are of a nervous disposition add a 10 k resistor in series with the control wire.

| improve this answer | |
  • Thanks @joan. I am trying to understand how to calculate the limit of elements I can connect externally to the PI. – cor Nov 19 '15 at 13:55
  • There is such a variety of kit you can connect and a variety of means. If you have a particular scenario its probably best to mention all the kit you want connected. – joan Nov 19 '15 at 19:19
3

Please do not try to drive a servo (or multiple servos) directly from a GPIO pin. You will need to put a transistor in between, and provide a separate power source for the servo, as the RPi might not be able to deliver enough power to drive the Servo (depending on the voltage used to drive it, at 3.3V the RPi only has 16mA available, at 5V this is a little less limited). You can also look at prepackaged servo driver boards - the one I linked can control tens of servos with the same board.

And to answer your question: Yes, you can just connect 2 servos to the same signal, and they will do exactly the same movement.

| improve this answer | |
2

Yes, considering that you'll most likely not connect the servos power1 directly to a GPIO pin but just the control lines.

Note that a maximum of 16 mA per pin with a total current from all GPIO pins not exceeding 50 mA is a absolute maximum rating of the Pi, but it is unlikely to be exceeded with controlling digital inputs only.


1: That would be a problem in its own right.

| improve this answer | |
  • OP was asking about controlling, not powering the servo from GPIO. No transistor is needed for the control signal (if its 3.3V compatible). – cde Jan 27 '17 at 5:56
  • Gotta agree with cde here -- Phil's and your answers seem misleading in context. What do you need a transistor for? To toggle the power? Why? Unless there's a control signal, they don't draw any. And you don't need a transistor on the control line, standard servos are fine with a 3.3V signal. I agree that powering two servos from the 5V rail may get sketchy, but that really depends on the servo and the load on it. – goldilocks Jan 27 '17 at 12:39
  • @cde you're right, thanks for the hint. I was mixing that up... getting a little carried away over the fact what people try to connect to GPIO pins... – Ghanima Jan 27 '17 at 12:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.