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[on:]

My Goal:

My goal is fairly simple. I want to have a my VEX robot controlled entirely via my computer using the Ardunio MEGA 2560 Rev 3 as the interface between the computer and the Vex systems. I followed the wiring instructions at http://mykola.bilokonsky.net/2010/12/controlling-a-vex-motor-with-an-arduino-microcontroller/ (I did, however, substitute the 9v battery for the stock Vex battery pack) and I'm having no trouble at all controlling the motors.

The Sticking Points

Is the power isolated sufficiently from the signal lead in the Vex motor so that a power spike caused by a stuck wheel won't fry the port on the Arduino? I'd rather not have to added mess of opto-isolators if I don't have to.

Point of interest

My ultimate goal is to have my robotic platform controlled via my computer with an ethernet tether and on-board telemetry from a 3 axis accelerometer, temperature sensor, humidity sensorand  Vex ultrasonic range finder with a completely separate (not run through arduino) video system using a wireless security camera. I have all the sensors and the camera. I simply have to get the sensors all hooked up(I've tried them all individually and they're simple to use) and the motors all running (I've had only one motor setup and running so far) and I'm done.

All in all a fairly simple but cool setup. Later I might get a wireless shield and sever the ethernet tether but that's not a priority for me.



 

[Reply #1 on:]

I did, however, substitute the 9v battery for the stock Vex battery pack) and I'm having no trouble at all controlling the motors.

At least until the battery goes dead, which will be real soon.

Is the power isolated sufficiently from the signal lead in the Vex motor so that a power spike caused by a stuck wheel won't fry the port on the Arduino?

That depends on the motor wiring. You should be asking Vex that, not us.

on-board telemetry from a 3 axis accelerometer, temperature sensor, humidity sensorand  Vex ultrasonic range finder

OK. What is this robot going to be doing? Opening and closing windows in a green house?

[Reply #2 on:]

Is the power isolated sufficiently from the signal lead in the Vex motor so that a power spike caused by a stuck wheel won't fry the port on the Arduino? I'd rather not have to added mess of opto-isolators if I don't have to.

Since the Vex motors are basically just continuous rotation servos, you're fine.  You shouldn't get any sort of power spike through the signal wire to the Arduino.