servo max number notes

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A Raspberry Pi has enough GPIO pins to power and drive multiple servo motors.

It’s very easy to place too much load on the PI, causing low-voltage conditions, freezes and restarts. The most reliable way to power servos is with separate power supply.

However for many users, especially with limited resources, the convenience and simplicity of powering and driving the servos directly from the Pi is huge.

What motors can typically be driven in this way before running into problems?

  • You can not power any servo from a GPIO (pin). The GPIO can not supply anywhere near enough current. You can probably power a couple of 9g servos from most Pis 5V power rail. However even that depends on the servo load and the power supply to the Pi. This question has too many unknowns. – joan 6 hours ago
  • @joan By GPIO pins I mean the 40-pin header, generally referred to as the GPIO header even if not all the pins on it are strictly speaking GPIO pins. As my answer below indicates, it’s possible to power a least three servo motors reliably from the 5V rail. – Daniele Procida 4 hours ago
  • @Daniele Procida, Ah, let me see. (1) The Rpi 40 pin header has two kinds of pins: (a) Power pins: 3V3 and 5V0, (b) GPIO pins: input/output pins of 3V3 logic. You seem to ask about the power pins and NOT the logic GIPO pins. (2) So to answer you question, we need two pieces of data: (i) What is the maximum current of the 5V power pin (call it “Rpi5Vmax/current”), (ii) What is the maximum current of Sg90 (“Sg90maxICurrent). Example, max number of SG90 servos = Rpi5VmaxCurrent / Sg90maxCurrent. If my guess is correct, I can find the max number of servos (or combination) for you. – tlfong01 9 secs ago   Edit   


Where multiple motors are indicated as working reliably, this means that all motors were in operation at the same time, over an extended period of time.

Numbers indicate the largest number of motors that were tested simultaneously.

Reliable under all tested conditions

Power source: official Raspberry Pi PSU

  • TowerPro SG90 * 3
  • TowerPro SG92R * 3
  • Futaba S3001 * 2, TowerPro SG90 * 1
  • Etronix GS045 * 2, TowerPro SG90 * 1

Power source: OTG power supplied over USB

  • TowerPro SG90 * 3
  • TowerPro SG92R * 3
  • Etronix GS045 * 1

Not reliable

Power source: OTG power supplied over USB

Load causes restarts or freezes:

  • Etronix GS045 * 2
  • Etronix GS045 * 1, TowerPro SG90 * 1

(Please feel free to add data based on experience to this answer.)

  • this cannot possibly be the answer to the question … the question asks about supplying power to servos from RPi GPIO pins … this list may be related to controlling servos, but not to supplying power – jsotola 5 hours ago

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