Attaching non-vex 2 wire motor to the Vex controller

Is there a way to use a non-vex motor with the vex controller. I have a spare windshield washer motor (2 wire) that does work with the Vex controller (at least the power is ok) but I’m not sure how to correctly hook it up so I can send commands to have it go forward and then backward using the online terminal.

It works with the Victor 884 speed controller fine but I would like to use it directly hooked to the controller with no speed controller. I’m just not sure what to do with the 3 wires on the servo wire when the motor has only 2.


P.S. if anyone is interested we had a massive turnout at the SciFi Robot invasion at MegaCon in Orlando a few weeks ago. I use Vex to power my life size Robby and B9. Bender is also getting a Vex Module to turn his head (maybe).
There’s pictures posted on

well, black is for ground, red is for positive, and white is for the signal (i think). so i would plug the motor into black and white.

Hey Paco,
I tried different combinations but they didn’t seem to work quite right with that extra wire. I thought there might be some sort of adaptor or something.


The adapter is called a Victor 884.:slight_smile:
The Vex can’t directly drive a motor. The outputs are logic level signals.

Yup. One wire is power, always on, one is ground, one is signal- the signal won’t drive anything, gotta use a speed controller to convert what the processor says to something the motor can use.

Thanks guys. That makes sense. I guess I’ll have to stock up on a bunch of Victor 884’s. But they aren’t cheap unfortunately.

One other question is I’m hoping to hook another vex controller I have to a Vantec RDFR23 with two custom modified NPC 2212 motors (lower RRM’s). I am hoping the vantec speed controller will talk to Vex but I haven’t received them in the mail yet to try. It will power a 1:1 R2D2. I’m comfortable programming the Vex and want to stick with that for all my robot projects. The Vantec controller is very smooth and recommended by a friend who does the robots (especially R2’s) for a famous theme park worldwide.

Vex has been a great way for me to learn robotics and animate my robots.

there are many h-bridge motor controllers out there. I use the allegro micro a3968 dual h-bridge chip myself for most low current motors. It can handle up to 650mA per motor. You will need 4 i/o pins to control 2 motors, however. With this you can set the motor to forward, reverse, brake, or free spinning. With one more pin you can do PWM speed control on the motor too. This chip costs about $2.00.

There is also

This is a quad half-h-bridge which can be configured for a dual-h-bridge or can be used to drive a stepper. This also requires 2 i/o pins for each motor to set on/off/direction and a third pin can be used to do PWM speed control. This also is less than $2.00. This chip is capable of handling up to 1A motors.

There are multiple options out there that are considerably less expensive than those massive motor drivers.


Ray Moore

Get Moose and Squirrel!

The Vex Controllers outputs are standard PWM. If your motor is PWM and low enough Current (the Vex motors are 5mA to 1A, see Vex Robotics Motor Kit) it should be just fine, otherwise you need a Victor 884 (or similar device) to drive Higher Current Motors…

Ray, I looked at those links you posted and examined the PDF specifications.

I wish there was a book “h-bridge motor controllers for dummies”. I looked at the chip schematic and it was waaaaaaay over my head. Now if I knew what to solder to all the 16 pins in simple words …like … from the servo wire red to pin1, black to pin2, white to pin3, input power to 4 and 5, output power to 5 and 6 etc. But I’m guessing it’s a lot more than that and may need capacitors, diodes and other fun electronics. I’m in over my head here but still very interested.

Because if I could build my own controller with that chip then I could automate so many more appendages of my robots using inexpensive surplus motors.

Thanks for the info !

If you are interested I can draw up simple control schematics for both of those chips. They are super simple to use.

Ray Moore

Get Moose and Squirrel!

I may be wrong but I believe there is no way to use a “wire converter” to convert 2wires to 3. Because you still have no way to get signal you just have an extra wire.

Ray, I would be grateful for the simple schematics ! My email is tap5s @

Thank you very much !


Another R2 builder, Nice to see someone else has faith in the Vex system.
I’m adding it to my R2 as I build.

I agree Vex is a good choice for the R2 project Calvin. Vex will be used to automate my R2’s dome and periscope for random movement and using the RC to maneuver R2 around. Automating audio tracks with vex is also on my list of “to dos”.

I tried using a Vex motor to turn my B9’s torso (exactly the same size as an R2 Dome) but it was just too much strain for the little motor no matter how many different ways I changed the gears.

Did anone here read this recently revived thread, High Speed DC Motors using H-Bridge and PWM??

Marko has been a VERY LARGE HELP in pointing me in the right direction.
With his help, I have my R2 dome responding to movment on each side using Ultras and having the ability for me to take over using the remote.
I plan to use the Vex in the dome to control everything that is needed and another Vex in the body to control it’s needs.
I found a remote system I want to use with the Vex for sound with animation,
But I’ve got to figure out how to wire it.
This is the remote :
Man that made a mess.
Any help would be a Blessing.

I would love to see how you programmed for the sensors and the Dome turning. That’s my ultimate goal but still pretty fuzzy how I’m going to do it. I’m kind of just blundering through all this technology to get my robots moving but I do learn something new every day.

I have a similar sound system you linked to but can’t figure out how to activate it using the Vex system. I experimented with it a few months ago but put it on the back burner. My version of that sound card (I believe it’s the CF Sound III system) that has a small amplifier attachment and uses compact flash cards to store the sound bytes. Here’s a link to the CF Sound III site with diagrams for wiring.

It MAY be the same as your setup. Don’t be misled by the picture on the main page

Man that made a mess.
Any help would be a Blessing.

OK, I am getting back into Vex Stuff… (After a “burst” of FRC)

So how does this remote work, One Transmitter, One Receiver, 12 different Buttons that Energize 12 different Relays???

If so, you can use each of the Relays, just like a Switch (Bumper or Limit), then program for them. Remember that if you need Inputs configured to Analog, they need to be the Lowest Numbers, so make your Relays start at I/O #16 and work down to #1. Your Program on the Vex Controller would respond to each of the Digital Inputs… You would most likely have all the Relays on One Vex Controller, because of the Dome that can spin all the way around, and there would be no communication between the Two Vex Controllers… It would be possible to use something like Blue-Tooth to RS-232 adapter, then you could link the Two Vex Controllers on a Serial Port, Wirelessly…

The code I posted before (More Buttons), could be modified for two different Vex Controllers, with Two different Receivers. Each Controller starts in a Different State, so that you press a button on the Vex (Channel #5 or #6) to Switch the States to determine which Vex Controller responds to the Vex Transmitter… Would you like to see an example???

I plan to use that Sound System in R2 also.
The link to the Ebay system is just a remote with a reciever, But it works with that Sound Sys.
The programming I used in the R2 Dome, I have to give most of the credit to Marko. I was stumbling around with it, But he added some code that I would have never figured out.
My blog is stop by and leave a comment so I’ll know you where there and there’s some links to some small vids on there that will show my dome working.
I used the infared tracking kit as no touch switches and they work pretty good. This way it does’nt slow down the dome like it did when I was useing the bumper switches.

The CFSound III looks like you can pre-configure it and then just trigger Sounds to start with a single input. But if you were to get an RS-232 to TTL converter, you could connect the Vex Controller to the Serial Port on the CFSound III and modify the Basic program in real time from the Vex.

Remember that the Vex Controller has Two Serial Ports, and the One is only used while re-programming… So you could link two Vex Controllers together and then have one of the Controllers link to the CFSound III.