I think those analog indicators could be driven through PWM without the need of a potentiometer equivalent. Their moving coil and needle inertia would work as i

I think those analog indicators could be driven through PWM without the need of a potentiometer equivalent. Their moving coil and needle inertia would work as integrator or low pass filter wrt the pulses, so just applying a square wave that goes from 0% to 100% duty cycle would move the needle from min to max, with 50% that should go to half scale after some calibration. The signal should be high enough in frequency so that the needle doesn't dance around, 100Hz would be more than enough, and current should be limited by placing appropriate resistors on both + and - pins of the indicators, then the central pin would go to a push-pull capable gpio (that is, capable of both sinking and sourcing current), or adding a power opamp to normal gpio ports, in that case any ucontroller could be used, including small ATTiny ones capable of software USB implementation.