oops i think i need a servo controller

I have a HS-5955TG http://www.servocity.com/html/hs-7955tg_servo.html
I was originally going one way (tank steering) with my ROV. so I bought a dual motor controller Pololu - Dual VNH3SP30 Motor Driver Carrier MD03A.
I have switched gears (lol) and am going with drive wheels in back and standard steering in front. Hence the servo I got.

Now I just got the sinking feeling that I cant run the servo directly from the arduino and I suspect my motor controller doesnt work with servos?

Any thoughts or am i stuck buying another part and waiting for it to get here ;( just got my servo in the mail and was all hot to install it.

I'm searching around trying to find how much amps the servo actually uses but I havent stumbled on the datasheet yet.

jointtech:
I have a HS-5955TG http://www.servocity.com/html/hs-7955tg_servo.html
I was originally going one way (tank steering) with my ROV. so I bought a dual motor controller http://www.pololu.com/catalog/product/707.
I have switched gears (lol) and am going with drive wheels in back and standard steering in front. Hence the servo I got.

Now I just got the sinking feeling that I cant run the servo directly from the arduino and I suspect my motor controller doesnt work with servos?

Any thoughts or am i stuck buying another part and waiting for it to get here ;( just got my servo in the mail and was all hot to install it.

I’m searching around trying to find how much amps the servo actually uses but I havent stumbled on the datasheet yet.

The page you quote from servocity says:

  • Idle Current Drain (4.8V): 9mA at stop
  • Idle Current Drain (6.0V): 9mA at stop
  • Current Drain (4.8V): 220mA/idle and 3.4 amps at lock/stall
  • Current Drain (6.0V): 300mA/idle and 4.2 amps at lock/stall

The usual wisdom is you can run servos from your Arduino without a servo shield, providing you use a split power supply and don’t have the Arduino power the servo from its supply (small hobby servos might work). Here is a writeup that somebody else wrote up about wiring servos for RC cars: http://rcarduino.blogspot.com/2012/04/servo-problems-with-arduino-part-1.html.

A servo shield or controller can help, particularly if you are trying to control lots of servos. A few servos should be fine providing you deal with the power.

Note in the Servo documentation is buried the line is the following:

The Servo library supports up to 12 motors on most Arduino boards and 48 on the Arduino Mega. On boards other than the Mega, use of the library disables analogWrite() (PWM) functionality on pins 9 and 10, whether or not there is a Servo on those pins. On the Mega, up to 12 servos can be used without interfering with PWM functionality; use of 12 to 23 motors will disable PWM on pins 11 and 12.

I’ve seen several postings recently where users had a LCD display on pin 9 or 10, and when they added the servo, the display stopped working.

awesome thanks. Ill wall wart the servo for testing and get a voltage regulator to step it down from my 12v battery when im ready to go off the workbench. Looks like I might do some soldering tonight!!
i just looked at the page again and there it is. i looked in that section a few times and i think my brain didnt understand it was looking for current drain and passed my eyes right over..
thanks again.

jointtech:
awesome thanks. Ill wall wart the servo for testing and get a voltage regulator to step it down from my 12v battery when im ready to go off the workbench. Looks like I might do some soldering tonight!!

You are welcome. Hopefully it works. I know the frustration of waiting for parts by mail, particularly when a company I thought was US based shipped from China instead.

jointtech:
i just looked at the page again and there it is. i looked in that section a few times and i think my brain didnt understand it was looking for current drain and passed my eyes right over..
thanks again.

Spec sheets have a way of doing that.

works great on the sweep and knob sketches. Now to hook it to my joystick and i’m offroading. XD