Powering the Raspberry Pi servo hat only when needed

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rawexp
 
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Powering the Raspberry Pi servo hat only when needed

Post by rawexp »

I would like to use the Raspberry Pi servo hat in a device that needs to remain powered by batteries for many days. Occasionally, I want the servo to rotate the set-up. I do not want the servo constantly powered up as it may only be needed for a few seconds every few days. Is it possible to cut power to the servo when it is not in use via the hat? If not, I can use a relay to cut the servo power input via the barrel jack on the hat but would this completely cut power to the servos or would the hat attempt to power the servos from the raspberry pi 5V supply in the absence of the external supply? Any advice would be much appreciated.

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adafruit_support_bill
 
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Re: Powering the Raspberry Pi servo hat only when needed

Post by adafruit_support_bill »

In CircuitPython, you can set the servo angle to 'None' to stop sending control pulses. Most servos* will go into an idle state and cut all power to the motor. There will still be some idle current draw from the control circuitry, but it will be a lot lower than with an active signal.

* Note that we have encountered a few servos that will continue to hold the last commanded position when the signal pulses stop. For these servos, the only option is to cut power completely.

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rawexp
 
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Re: Powering the Raspberry Pi servo hat only when needed

Post by rawexp »

Ok thanks, I will test. If I cut the power to the DC jack on the hat, would that completely cut power to the servos or would they draw power from the Pi instead?

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adafruit_support_bill
 
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Re: Powering the Raspberry Pi servo hat only when needed

Post by adafruit_support_bill »

The servo power circuitry is completely separate from the control circuitry. So cutting power to the DC jack should cut power completely to the servos.

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