Vex robotics Transmiter

[steamboatmodel]

Hi has anyone used the Vex Robotics Add on Transmitter. there seems to be a lot of them around on ebay.
Regards,
Gerald

[soft2]

I've used it. It's a typical entry level r/c tx, decent quality with basic programmable functions. Boats and cars only. No planes/heli.

[steamboatmodel]

Did you use the receiver that comes with it ? if so how do you modify it to use servos?
Regards,
Gerald

[steamboatmodel]

I found a site that shows how to roll your own RC and think the decoder from it will work. http://web.telia.com/~u85920178/use/rc-prop.htm
Regards,
Gerald

[CrashingDutchman]

I am not suggesting you to use the Xtreme Power systems product, but I think Jim Drew from this company has said it should work with their system.

[mjsas]

I was at a robot event and Vex radios were being used with standard ESCs so I would think they have standard servo outputs. I am 90% sure they did not have any interface circuits, just plug and play.

[soft2]

Did you use the receiver that comes with it ? if so how do you modify it to use servos?
Regards,
Gerald
You can use any RC receiver on the same band. I used the reciever that came with it and wrote a simple program for a $3.00 microcontroller to divide the signal between servos. This gave me the tremendous advantage of being able to custom control each servo output. You can program the tx for some customization but much more freedom at the rx end of things. For example servo output could be based on the state of something going on in your model that the tx wouldn't have any knowledge of. Once I programmed it to run a stepper motor instead of a servo on one channel, and one time an LED array. Also those buttons on the back of the tx for ch 5 & 6, those normally increase/decrease the standard 1.500ms pulse by 500us but I changed one so it incr/decr the pulse by 80us each time you press the btn with a cumulative effect instead of the standard behaviour of just returning to middle position when you let go of all the btns. Lots of cool stuff you can do with that pulse train.

I don't see why you couldn't use Harry Lythall's circuit but jeez with all the required calibration etc it's easier just to use a microcontroller and then you have infinite control of the signal if you want. You need a pull-up on the output of the rx about 20k.

Good luck.