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Adafruit Foot Pedal Potentiometer - Sewing Machine Speed Controller [ADA3739]
We've had a foot pedal switch in the store for a while but some people have contacted us asking if there was a way to retrofit it to perform variable speed control, like a potentiometer. And here it is! This is a Foot Pedal Potentiometer (a.k.a Sewing Machine Speed Controller).
This is a really nice quality one, very sturdy, with a friendly 3.5mm 'audio' connector on the end, so it's incredibly easy to integrate into your project. You can use a 3.5mm terminal-block adapter, in-line wired jack, breadboard jack, or a panel mount jack. A lot of the cheap samples we looked at have a wall plug, are very low resistance (because they're meant to go in-line with the mains power) or are not very durable.
When no pressure is placed on the pedal, you'll read about 20 K Omega. When pressed down all the way, you'll read about 1 K Omega, and the resistance change is linear with the motion. Connect one side to ground, then the other side to a 10K resistor pull-up to your microcontroller's logic voltage. Then read the divided analog voltage, like you would with a photo-cell or other 'resistive' type sensor.