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bodhibuilder
09-29-2008, 09:08 AM
Hey guys,
I need a servo controller for about 7 servos and Iím trying to decide between getting the Pololu USB 16-Servo Controller and the Phidgets Advanced 8 Servo controller.

Which one would you recommend for me, considering Iím new to robotics and I have never done servo controlling before? Which of the 2 has the best documentation, is the easiest to program from C / VB, and has the most resources for understanding how to make it work?

Some of the servos I will be trying to control are:

Hitec HS-805BB Giant Scale Servo Motor
Hitec HS-755HB Giant Scale Servo Motor
Hitec HS-475HB Servo Motor
Hitec HS-422 Servo Motor
Hitec HSR-1425CR Continuous Rotation Servo

darkback2
09-29-2008, 10:25 AM
I have both...well sort of, and have never been able to get the pololu to work. That isn't to say that you couldn't...but I didn't...As for the phidget 8, I have used several phidget 4s...haven't gotten into the phidget 8 yet. The phidget 4s are pretty solid. In using them for several years and out of the 7 that I have only one died...and that was after several years. One problem I have noticed with the phidget 4s is that the first channel is powered by the USB on the computer. This makes that servo weaker than the others at times. My new controller of choice is the SSC-32...its cheap and easy to use, and can control a lot more servos.

Hope this helps.

DB

Alex
09-29-2008, 11:37 AM
With the Pololu, you'll need to send commands via a SerialPort object (not sure what it's called in C). Programming this way can be very fun, but if you're new to robotics and don't know how to communicate through a SerialPort, you're probably better off sticking with a Phidget:)

Who knows though? Maybe someone wrote a wrapper class for the SerialPort commands with the Pololu..

darkback2
09-29-2008, 11:43 AM
I wrote a midi to SSC-32 program. I think I posted it. If not let me know and I will.

DB

Adrenalynn
09-29-2008, 11:47 AM
I have a C# demo tutorial up here for controlling the SSC32 completely raw from C# - doing it with MSVC is almost identical. It could be modified for the Pololu in about ten seconds.

bodhibuilder
09-29-2008, 12:44 PM
Ok, so since I want it to be as easy as possible I think I’ll go with the Phidgets Advanced 8 Servo controller. Shouldn’t it be just like the Phidgets 4, darkback?

(Even though the SSC-32 does seem like a good option, I want something with a USB – to make it as easy as possible)

Hopefully there is enough documentation and information online that I’ll be able to figure out how to control these servos using the Phidgets 8 :)

I also have a question about the battery/power supply for those servos, but I guess I should post that in the ‘energy’ section of the forum….

darkback2
09-29-2008, 01:26 PM
Ok...so for power, I just used a 6 volt wall adapter that fit, cut the cord, and spliced in an RC battery adapter. Then I could either plug it into the wall, or into an RC battery depending on how charged things were...

Connector (http://www.allelectronics.com/make-a-store/item/CON-210P/2-CONDUCTOR-RC-BATTERY-PLUG/-/1.html)

DB

Adrenalynn
09-29-2008, 01:37 PM
Make *really* sure that the wall adapter has both adequate current handling capacity and, even more important, is WELL REGULATED.

It's not uncommon to see a 6v wall-wort spit-out 9v, 11v, 18v, 20+v under no-load. Don't assume, slap a multimeter on it or live with the smelly remains of what used to be a servo. ;)

bodhibuilder
09-29-2008, 02:01 PM
That sounds like something I should do, but could you elaborate more about what exactly you did? – what wall adapter that fit did you use and where can I get one? (i'm somewhat new to these terms and 'modifications')
(is this it: http://www.robotshop.ca/home/products/robot-parts/power-systems/batteries-chargers/hitec-robonova-quick-charger.html (http://www.robotshop.ca/home/products/robot-parts/power-systems/batteries-chargers/hitec-robonova-quick-charger.html))

and how did you splice in an RC battery adapter?

If I have about 7 servos, I should probably have more than just one 6V 2800 mAH battery pack, shouldn’t I? I was thinking of making a battery holder/box where I could hold/connect 5 rechargeable energizer batteries (providing 1.2 x 5 = 6 V of power), would that be sufficient?