I have an old GE lightmeter that has a selenium cell hooked to an analog needle-style current meter, and computer dial on the front for calculating settings. The selenium cell is too old to be accurate but the meter itself is very cool.
I want to gut the meter and put in digital guts and a silicon sensor. Using a microcontroller I can read the sensor and then drive the current meter so that the needle readout works just like on an unmodified meter. The issue is I'm trying to figure out how much analog electronics I'm going to need to drive the meter. Does anyone know how much current these types of analog current meters range over, and whether they are linear or log? Or maybe you know how much current selenium cells put out? My microcontroller has a 0-5v analog output which I suppose I can just run through a resistor for a current source, but are we talking microamps here or mililamps?