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I am building a project that uses a motorized slide potentiometer with a Raspberry Pi 4, for the purpose of controlling multiple audio sources (such as system volume, VLC, OBS, and any other I can interface with). I acquired this motor slider and this motor controller, and when looking at the slider's spec sheet (PDF), I read that the motor expects 10V, though in testing with a multi-voltage power adapter, it happily moves fairly snappily at 9V (and less and less snappily at 7.5V, 5V and 4.5V, and doesn't work at 3V). The motor controller is rated at 1.2A constant, which is well within the 800mA the motor is rated at.

In order to move the slider at a good speed, is it possible to make or buy a step-up converter from 5V to 10V and connect it directly to one of the 5V pins on the RPi (which AIUI is connected directly to the power rail from the USB power adapter, in my case a 3A adapter), or would it be better to get higher voltage power from another source such as the power adapter I used for testing?

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  • \$\begingroup\$ How many sliders can activate at once? \$\endgroup\$
    – Andy aka
    Feb 5, 2021 at 12:42
  • \$\begingroup\$ The project only has one - the rest of the space in the case it is mounted in its consumed by a 7" touchscreen. \$\endgroup\$ Feb 5, 2021 at 17:03

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You could do either way. If you have a 10/12V source readily available it's easier that way. DON'T connect it to the 5V rail of the pi to avoid magic smoke. You only give it to the VM rail of the motor controller. If you have 12V I'd recommend to use PWM or a suitable resistor to pull down the voltage on the motor to 10V, it will last much longer.

You can build/buy a suitable converter to make 10V from the 5V rail, subject to power requirements: 1A at 10V needs a little more than 2A from the 5V rail, do not overload your power supply! Look for "boost converter" "stepup converter" or even "buck-boost converter" and check for the ratings.

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