Motors with integrated sensors

I would love to see some motors with integrated sensors and slightly more powerful motors.

Here is the specs that it would have to have

%25-%50 stronger motor
Integrated quadrature encoder
Temperature sensor if possible
and any other sensors you might be able to jam into it.

Having this would make it easier to use an optical shaft encoder because right now every time i build a robot the shaft encoders end up in weird places with chains attached and it just gets really ugly. Basically the encoder would be in the motor making lift a little bit easier.

Ya that would be pretty awesome with the opt. enc. in the motors (like Lego NXT has)! But why would you need to have a temp. sensor?

I would want a temperature sensor so i could tell when the motor was getting hot, it would be cool to retrieve the data and store it so you could graph temperature vs Running time ect…

As for the built in shaft encoder that would come in handy, i build all sorts of little parts that have no room for a shaft encoder so this would be a life saver.

I would also like to have motor temperature feedback. During competition, my robot’s motors became REALLY hot and I did not know wether I should keep driving the robot or stop. Feedback from a motor temperature sensor would have been great.


I found such a motor at an Electronic Surplus Store (ESS in Manchester NH, ask for Peter) and plan to use it on some of my new Vex and Vexplorer projects. It will be used with my Schmart DC Motor Controller and Schmart Robot Controller that provides the Vexplorer the ability to be programmed using Microchip dsPIC C30 C compiler and MPLAB. You can see the progress I have made at the SchmartBoard site. SchmartBoards are the Vex equivalent of DIY rapid prototyping boards used for Surface Mount Components (SMT) that seem to be prevalent these days.

Yea having all of those sensors in a motor would be awesome.

But then vex would have to make another motor which is pain.

Well, if you are going to make a smart motor with built-in sensors, what I want is a current sensor. That way you could compare the actual rotation speed against the PWM setting and current draw to figure out how much load the motor is under. Kind of a poor-man’s torque sensor.

This would allow you to set virtual limit switches in software, so you can do things like close the claw until you get a certain amount of strain on the motor.


  • Dean

You may also want to use a Freescale Pressure Transducer as feedback to the controller.

I agree, a motor with current sensors would be awesome allowing digital limit switches as Quazar had said. But remember how much we want in this motor.

A current sensor, a quadrature encoder, a temperature sensor ect…

Right there that is 5 pwm cables coming out of 1 motor lol!

I see. It would be cool to have a temp sensor to watch that. If vex did make a motor like that I would want them to make it where the PWM cables can be unplugged for the sensors, but lockable to hold them in place.

Well, if you are putting this many smarts in the motor, no reason to limit yourself to PWM/analog. You could probably get by with one PWM to run the motor, and one digital interrupt that shifted in serial data for all the sensors.

Alternatively, you could just make the motor connect to the TTL serial port. You could design the smarts in the motor such that they could be chained in a big loop:
*]Vex Tx -> Motor1 Rx
*]Motor1 Tx -> Motor2 Rx
*]Motor2 Tx -> Vex Rx
[/LIST]That would require the motors to draw power from some other source, but if you are going to make a super motor, you are going to want more power anyway…

Sounds like we are designing a nice $99 motor :rolleyes:

  • Dean

a temperature sensor would be nice for another reason, you could program it to shut-off if it reachs a certain temperature, to prevent it from damaging itself

Thats another good idea, to have like ports on the side that you could plug a male-male pwm cable into.

That way you could use the sensors that you want.

The VEX motors already have a temperature sensor, you just can’t read it. The motors will shut off if they get too hot.

I knew it had a built in sensor but it would be cool if it was like the ultrasonic sensor and reported numbers back for the degrees in Fahrenheit.

Can you hack into the on board temp. sensor on the motor?

Not without voiding the warranty, even then I doubt it. It is likely more “mechanical”, not sure of the right word, basically I doubt it is smart, i.e. running any sort of code.

I didn’t think so…but heck, ask anyway!

I think robofreak is onto something with the thermal sensors. I expected the effects of heating to be noticeable, but minor. However, in my traction tests, I’m seeing the motors loose about a third of their power within a minute of being placed under a heavy load (they felt quite warm).

I tried this with both Vex PWM and Vexplorer DC motors and got the same result.


  • Dean

If this is going to be a $99 there needs to be more lol!

We need all of those sensors plus

There should be a small capacitor start just to give the motors that kick when they start up to get them really going.

But yes i cannot see a motor such as this for cheaper than $99.

If they don’t want to design something like this i would really like to see motors that are like r/c racing grade with there own power supply’s which would allow for really fast speed and lots of torque.