Need to control rc model relays (that operartes high-voltage motors). Is it possible to make with RPi without additional hardware? Any links to the solution?


2 Answers 2


Not a conventional relay, you'd have to use a very small relay (if you can find one with a 3.3V@16mA or less coil) to switch a larger one and then be careful that the back EMF didn't damage the GPIO pin.

Much better idea to just use a transistor if it's just a single relay

However it may be possible to find a solid state relay that's suitable. Although they tend to be more expensive than a transistor+conventional relay.

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  • He wants to control relays inside his RC cars - not add more relays. Also he does not state the model of relays so the question is unconstructive.
    – Piotr Kula
    Aug 24, 2012 at 10:55

not without additional hardware. I would take look at those arduino motor shields... they are capable of controlling several motors.

If you want to control a servo instead of controlling a motor directly, thw pwm output of the raspberry will help you - and no additonal hardware is needed because the servo already contains it. But afaik, the raspberry only has one pwm output - so you will only be able to control one servo easily. If you need to control several servos, a servo controller like this one will be helpful: http://seetron.com/sscasd2.html

  • You dont know that for sure. Maybe the relays are controllable via simple GPIO- How can you prove or disprove that - You are just making assumptions.
    – Piotr Kula
    Aug 24, 2012 at 10:57
  • You are right - this is just an assumption from my experience. But since the GPIO pins are not designed as drivers, it is not recommendet to use them as such. Chances are too high that you will ruin your Raspberry if you try...
    – rdmueller
    Aug 24, 2012 at 18:44

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