Shop OBEX P1 Docs P2 Docs Learn Events
Servo control — Parallax Forums

Servo control

bboy8012bboy8012 Posts: 153
edited 2007-12-21 22:17 in Propeller 1
I have seen and looked at the 32servo object, and also the 4servo object, my questions is there any site or documentation for servo control so I can get an understanding in spin? Or does anyone know of good sights that will help me out in developing a simple single servo object to just get the fundamentals down. Thanks

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Hunger hurts, starvation works!

Comments

  • deSilvadeSilva Posts: 2,967
    edited 2007-12-21 19:19
    Read the thread with my PWM Tutorial; the first program in it might bring up concrete questions. The operation of servos is extremely simple...
  • bboy8012bboy8012 Posts: 153
    edited 2007-12-21 19:30
    I was looking for that but didnt see it, can you post a link?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Hunger hurts, starvation works!
  • bboy8012bboy8012 Posts: 153
    edited 2007-12-21 19:33
    Found it thanks!

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Hunger hurts, starvation works!
  • Mike GreenMike Green Posts: 23,101
    edited 2007-12-21 19:37
    You might also look at the Wikipedia article on servo mechanisms. Do a web search on "wiki servomechanism".
  • deSilvadeSilva Posts: 2,967
    edited 2007-12-21 19:58
    Well I wanted to post this as a PDF.... pushed this to Xmas holidays as well.. Hm, It seems these ARE the Xmas holidays now smile.gif

    There are uncountable articles and descriptions concerning stepper motors and servos... I think no need to add to them...

    However...
    Servos contain a small electronic part which is controlled by a short pulse, between 1 to 2 ms length. Is it 1 ms then the servo keeps to its left elongation, is it 2 ms, then the servo keeps right, is it 1.5 ms then the servo centers. This is an internal feed-back operation: The position of the servo is - most simple! - internally read from a potentiometer and compared to the pulse length.

    This has to be done continously, but with a low rate of 50 per second only !

    This is the beauty of it: You need not care of all the internals! You pay a little bit more than just for the motor, and you have not the full range of motors available. This is not a problem in model market - you get masses of servos from 6g to 160g - but when you need more powerful equipment.

    Servos can generally be powered from as low as 4.8 V (though 6V are much better), but they can easily be CONTROLLED by 3V !

    That's also the beauty of them.

    Generating dozens of PWM signals is a snap for the Propeller!
    See here e.g. http://forums.parallax.com/showthread.php?p=685997

    Edit: Improved some bad figures from my bad memory...

    Post Edited (deSilva) : 12/21/2007 8:48:14 PM GMT
  • bboy8012bboy8012 Posts: 153
    edited 2007-12-21 21:06
    All I can say is wow to your tutorial. Can you give a little more explanation for a newbie to this language?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Hunger hurts, starvation works!
  • deSilvadeSilva Posts: 2,967
    edited 2007-12-21 21:54
    ???
    You know a little bit of SPIN, don't you? You have worked yourself through chapter 3 of the Manual, haven't you?
    So you should be able to change the first program into a "just one servo" program... Well, I am aware I could have commented it more thoroughly :-(

    Or are you referring to assembly language? Then there is another Tutorial, of course smile.gif
  • bboy8012bboy8012 Posts: 153
    edited 2007-12-21 22:04
    The spin I have a basic concept, its the assembly that throws me off.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Hunger hurts, starvation works!
  • deSilvadeSilva Posts: 2,967
    edited 2007-12-21 22:17
    It will take some time... There is no really "Basic Tutorial".. In this thread
    http://forums.parallax.com/showthread.php?p=668559
    you will find Potatohead's introductary work as well as my Tutorial, NOT for the beginner...
Sign In or Register to comment.