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

<R15a>
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…

//Andrew

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!