Servo controller...
Robot Groups | Search
User Password
Register Now! Lost Password?

General Robotics Forum - All aspects of robots and their applications. 

Bookmark this page:  YahooMyWeb Yahoo!  Google Google  Windows Live Favorites Windows Live  del.icio.us del.icio.us  digg digg  Add to Netscape Netscape
Subject Author Date
Servo controller... Franek 03-19-2005
If you were  Registered and logged in, you could reply and use other advanced thread options
Posted by Franek on March 19, 2005, 1:26 pm


I need to control a couple of servos using Atmel's AVR microcontroller.
Is there anything like a chip that could be controlled in a simple way
by the microcontroller and that would keep shooting pulses at servos by
itself? (for example when I want certain servo to change position, I
send some bits to the chip, servo repositions and microcontroller does
not have to take care any more)

I know I can build such pulse generator by myself, but I'd rather buy a
compact, tested and easy-to-use chip.

I'm more of a programmer then electric enthusiast. (:

--
Frank

Posted by Scott McDonnell on March 19, 2005, 2:08 pm


Normally, you would just connect the servo data line to a port pin on the
AVR, and use the timer in the AVR to create the pulse width frames. But, if
you don't want to do that, you could get a serial servo controller and
connect it to the USARTs on the AVR.

Scott


> I need to control a couple of servos using Atmel's AVR microcontroller.
> Is there anything like a chip that could be controlled in a simple way
> by the microcontroller and that would keep shooting pulses at servos by
> itself? (for example when I want certain servo to change position, I
> send some bits to the chip, servo repositions and microcontroller does
> not have to take care any more)
> I know I can build such pulse generator by myself, but I'd rather buy a
> compact, tested and easy-to-use chip.
> I'm more of a programmer then electric enthusiast. (:
> --
> Frank



Posted by Jeff Holinski on March 19, 2005, 2:57 pm


wrote:

>I need to control a couple of servos using Atmel's AVR microcontroller.
>Is there anything like a chip that could be controlled in a simple way
>by the microcontroller and that would keep shooting pulses at servos by
>itself? (for example when I want certain servo to change position, I
>send some bits to the chip, servo repositions and microcontroller does
>not have to take care any more)
>I know I can build such pulse generator by myself, but I'd rather buy a
>compact, tested and easy-to-use chip.
>I'm more of a programmer then electric enthusiast. (:


Parallax has a servo controller that runs 16 servos and takes input
from a serial port. (I assume the AVR has one) You can set position,
speed, and get read the servo position from the board. They're about
$40us.


Remove nospam_ to reply by email

Jeff H........


Lies, All lies. Don't believe a word Difool/sayNO says.
He fears the truth!

Posted by Thread Ender on March 19, 2005, 3:14 pm


> I need to control a couple of servos using Atmel's AVR microcontroller.
> Is there anything like a chip that could be controlled in a simple way
> by the microcontroller and that would keep shooting pulses at servos by
> itself? (for example when I want certain servo to change position, I
> send some bits to the chip, servo repositions and microcontroller does
> not have to take care any more)
> I know I can build such pulse generator by myself, but I'd rather buy a
> compact, tested and easy-to-use chip.
> I'm more of a programmer then electric enthusiast. (:
> --
> Frank

Unless you really NEED to do it with an external chip, you can just connect
to the PWM out pins on the AVR. They are essentially "Fire and Forget" in
that you set up the pulse width in a few registers then just write the
desired duty cycle to a register and the servo moves to that position. No
fuss, no muss! You do not have to write a bunch of ISRs or anything like
that. However, since you said you were a software guy, you could use the
timer ISR to make your own PWM on any pin and control a whole bunch of
servos. That is what most of the servo controllers that you can buy from
various robo-part vendors have.

--TE



Posted by Si Ballenger on March 19, 2005, 8:04 pm


On Sat, 19 Mar 2005 19:26:46 +0100, Franek

>I need to control a couple of servos using Atmel's AVR microcontroller.
>Is there anything like a chip that could be controlled in a simple way
>by the microcontroller and that would keep shooting pulses at servos by
>itself? (for example when I want certain servo to change position, I
>send some bits to the chip, servo repositions and microcontroller does
>not have to take care any more)
>I know I can build such pulse generator by myself, but I'd rather buy a
>compact, tested and easy-to-use chip.
>I'm more of a programmer then electric enthusiast. (:

The below servo control chip is a good deal for $7.

http://www.kronosrobotics.com/xcart/customer/product.php?productid 273&cat)2&page=1

Related Posts
  • Subject
  • Posted In
  • Date
Latest Posts
  • Subject
  • Forum
  • RSS

The site map in XML format XML site map
 other useful resources:
Official Robosapien Website
Lego Mindstorms Website

Contact Us | Privacy Policy