Use of discontinued parts in VRC

An encoder is a digital sensor that counts the number of degrees turned since the robot turned on. A potentiometer is an analog sensor that tells where a shaft is turned to within its range. Because a potentiometer is just a resistor whose value changes based on where the shaft is turned to, it’s much simpler, but more limited in where it applies (and much less exact than an encoder).


Potentiometers actually have a much higher resolution than the encoders. For the encoders its 360 ticks per revolution but the pot has 4095 in 260 deg.

That is correct, however that doesn’t mean that the extra precision is useful. Encoder ticks are guaranteed to be spaced by exactly 1 degree, while potentiometer “ticks” are just changes in resistance detectable by the analog-digital converter in the port, and are not guaranteed to have any consistent physical spacing. In fact, they tend to be not exactly linear, and they get gradually worse over the lifetime of the sensor. I’ll get some sample data to show what I’m talking about when I get a chance.

Makes sense, as you wouldn’t need anywhere near that accuracy. The sensor degradation is also interesting. Either way, I’ll stick to using the integrated encoders :smile:

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is that only for Vex, there should be a better encoder out there.

Yeah, the vex encoders have 360 ticks per revolution. Some stepper motor encoders have upwards of 8000.