Encoder Question / Recomendation

[RacerX]

Thank you for the suggestions thus far.

Again, learning so excuse any dumb questions.....

Would a potentiometer have the same programming as the encoder? Would it always know where say zero degrees is and where 90 degrees is, and everything in between? Or, would we have to set zero each time?

I thought I heard something about that with different types of sensors???

[adciv]

Originally Posted by RacerX

Would a potentiometer have the same programming as the encoder? Would it always know where say zero degrees is and where 90 degrees is, and everything in between? Or, would we have to set zero each time?

You'll read the position of the potentiometer (pot) using the analog in. The output is 0-5 Volts (assuming you use the 5V source on the roborio). You'd have to calibrate it yourself for 0 degrees but after that it shouldn't change.

[Jon Stratis]

Originally Posted by RacerX

Would a potentiometer have the same programming as the encoder? Would it always know where say zero degrees is and where 90 degrees is, and everything in between? Or, would we have to set zero each time?

programming is different. A potentiometer is an analog device. As you rotate the shaft, the voltage of the output changes incrementally. WPILib actually has a rather nice class (AnalogPotentiometer) that can be used for this - when you create the instance, you can specify the range of the potentiometer (They're sold as 270 degree, 360 degree, 3600 degree, etc) and an offset for where you want 0 to be. That way when reading values you'll get them right in degrees, positive or negative.

Oh, and another benefit to potentiometers... being analog devices, they're really easy to verify functionality with a multimeter!

[Alan Anderson]

Originally Posted by Jon Stratis

programming is different. A potentiometer is an analog device....

So is the US Digital MA3 that RacerX mentioned as the "encoder" that they're already using. If that is accurate, then it works exactly like a continuous-rotation potentiometer.