Cheap motor controller

[dpeterson3]

I am looking for a cheap motor controller for use on a ROV. Jaguars and Victors are a little expensive for my budget. I can soder up some H-bridges using TIP120's, but I am not sure the thruster billage pumps I plan to use can hanlde the PWM signal. They are like CIMS, so they aren't going to handle PWM well. Anyone know of anything cheap and good enough for my use.

[Andrew Bates]

Wow this is also something I've been looking into doing over the summer, building an ROV. I've been looking into a couple of motor controllers on sparkfun for use with an arduino. This one here is what I am thinking about using right now.

[daltore]

That 9A controller is probably a little lower-power than he needs if he's using motors similar to CIM's. And CIM's have no problem with PWM signals, in fact, that's what both the Victors and Jaguars use. If you mean the 1-2 ms pulse, that's true, those pulses are ONLY signal pulses, and are not designed to drive anything. If you can make your own H-bridge and you're absolutely sure you can get the MOSFET and capacitor values correct, and you know what reverse protection diodes are, you could use 2 diodes as splitters and hook the H-bridge up to the VEX motor controller found at the bottom of this page. It takes a 1-2ms pulse range and outputs a full-spectrum power PWM pulse used in the VEX motors. Maybe some voltage regulators to get the output in the right range of the MOSFET gates (or whatever the trigger is called, I forget the terminology for FET's, but you know what I mean). Good luck, and if you get it to work, post pictures and video!

[sanddrag]

You might look to the hobby sector. hobbypeople.net and towerhobbies.com How much current does your motor/pump draw? Does it need to be reversible?

[MrForbes]

The Banebots controllers seem to work fine on ROVs driving bilge pump motors....

http://banebots.com/c/ELECTRONICS

We are using prototype four channel motor controllers from Cathode Corner on our ROV for the NURC this year. My brother designed them just for us...not sure what the final price would be on them....

http://www.cathodecorner.com/esc4/

I'm sure David would get a chuckle out of someone inquiring, though!

david@cathodecorner.com

[billbo911]

Originally Posted by squirrel

We are using prototype four channel motor controllers from Cathode Corner on our ROV for the NURC this year. My brother designed them just for us...not sure what the final price would be on them....

http://www.cathodecorner.com/esc4/

I'm sure David would get a chuckle out of someone inquiring, though!

david@cathodecorner.com

In the link, it says the controller's input is:
"Control input: One or two vEx PWM signals on a 4-pin Molex header "

Is it safe to assume that the input signal referred to is the multiplexed PWM signal generated by the Vex Remote Control?

[MrForbes]

Yes, it's the signal from the tether port on the back of the vEx transmitter (or from the reciever, although we haven't tried it wireless)

[dpeterson3]

I thought the Jaguars helped make the PWM signal a little more linear to 'simulate' voltage change better than just a strait PWM. I knew they would work, but I thought a controller might be better. I guess I was wrong. I know how to build H-bridges and I know about feedback diodes. I just thought a cheap controller might be better than building one. I am not very good at PCB soldering. I guess the only way to learn is by doing.

[daltore]

All, let me repeat, ALL major brushed DC motor controllers with the current supply you need use PWM. It's generally better than straight voltage control anyway, you get more torque and efficiency out of it, and it's just easier to produce. And there are a couple of ways to counteract issues with linearity. The Jaguars do it for you, although no one quite knows why yet (even my contact with Luminary Micro says they don't know why they're so much more linear than the Victors), but even if you used a Victor or a Thor, you could just square the the signal speed out to the motor controller to counteract the natural square root curve they have. Linearity really isn't your problem, the biggest attribute of a motor controller would probably be its frequency and resolution (higher the better). I'd suggest just looking at price and current capability, and once you've narrowed it down, look at reviews. As long as there isn't anything too outstanding in the customer reviews, it should be okay.

[Justin Stiltner]

Look at the low end (cheap, not low current) speed controllers used for hobby brushed motors. I can pretty much guarantee that they will be cheaper than the price to build one yourself.
An example
http://www.bphobbies.com/view.asp?id=A0780190
I have used this company a few times, they are in new jersey (not just a front there, they actually ship from there)
It may surprise you to see they have a 10A brushed speed controller for $13
Would I trust my $$$$ helicopter to this super cheap speed controller, probably not, but something that will not "crash and burn" if the speed controller dies sure.

[MrForbes]

Do any of those inexpensive aircraft speed controllers have reverse?