Electrical – How to use an 2-axis accelerometer as a potentiometer?


I've got a couple of Memsic 2125 accelerometers around and wanted to try to use one of them to replace a pair of potentiometers in a circuit (x axis replaces pot A, y axis replaces pot B).

How would I go about converting the output signal of the accelerometer into resistance? Along with that, how would I limit the resistance to a particular range?

(Apologies if this is a rather basic question – I'm a tinkerer and am pretty early on in my EE journey!)

EDIT: Added from comments per gbulmer's suggestion:

So the application will be a guitar pedal or something like it, so let's try with something simple. Say using just the x axis to control the fuzz pot in a simple NPN fuzz face.

NPN Fuzz Face schematic

Best Answer

A quick-n-dirty way would be to convert your accelerometer's digital outputs to analog as shown in the data sheet at the bottom of page 5. Then you could use that voltage to inject current into an ordinary transistor (like 2N2222, et.al.) That would cause the transistor to conduct more or less current depending on the voltage/current going into the base of the transistor. You could replace that 1K ohm "Fuzz" pot with your accelerometer-controlled transistor.

The volume control would be a bit more tricky. But you could use a similar "shunt" circuit to "short out" more or less of the audio output signal with another transistor connected like the "Fuzz" circuit.

A more proper method would be to use the digital outputs from the accelerometer into a microcontroller (Arduino, et.al.) and then use the microcontroller to control a couple of digital potentiometers which could be directly substituted in your circuit.