2-Wire Servos

With the world of VEX Motors moving into a 2-wire era, are there plans for 2-wire servos?

I doubt it. Honestly I do not know why the new motors are even 2 wire. The cortex is 3 wire and personally I rather have the new motor 3 wire and not deal with the motor controllers. They are a pain to run in the wiring and they are a safety hazard at times.

Complete integration of 2-wire modules would allow VEX to introduce a 2-wire cortex.

Vex Servos in a competition match are problematic because they don’t hold position when disabled, so they have very limited uses.

A motor with a potentiometer (or motor-back-encoder) can be programmed to act like a servo, and is superior in every way, so I forsee very little demand for a new 2-wire servo.

What would you want to use them for?

The vex 3-wire motors weren’t really motors at all. They were really servos with the potentiometer taken out to make them continuous rotation servos. There is actually a common modification to regular servos to make them continuous rotation servos (might not be legal for VEX). The two wire motors are ‘true’ motors.

If vex made 2-wire servos, I feel like they would need some sort of redeeming quality in order to be useful, like not counting towards your motor limit but making it so you can only use a maximum of 2. I don’t know. Something like that.

Not entirely true. I have made all of our servos into continuous 3 wire motors with a simple gear change and re-adjusting the potentionmeter inside.

I meant that I didn’t know if that was legal for (highschool)VEX. Are you sure that it is?

I am not sure if it is legal however I would assume it is. They allow you to change your gears if they break and your only adjusting an internal sensor without reprogramming or doing any type of soldering

Motors, extension cords, sensors, controllers, battery packs, and any other electrical component of the VEX Robotics Design System may NOT be altered from their original state in ANY way.

I don’t believe that modification is legal…


Actually, that wouldn’t be possible. A servo by design consists of a control circuit that compares the input signal to the feedback signal from an internal sensor on the output shaft and then moves the motor accordingly.

The 3-wire motors where simply converted to 2-wires by removing the internal control circuit which has no internal feedback sensor- like a servo modified for continous rotation.

The internal control circuit could be removed from a servo, but then it would require more wires not less. You would have the 2 wires from the motor plus the wires from the internal feedback device.

I see. I was wondering why they had not converted servos to 2-wires like motors. Thanks for clearing that up!