Shop OBEX P1 Docs P2 Docs Learn Events
HB25 and homemade power servo? — Parallax Forums

HB25 and homemade power servo?

moomoomoomoo Posts: 27
edited 2008-08-01 18:24 in General Discussion
Does anybody have an idea on how I can attach a pot to the HB25 to give the gearmotor a position reference, just like a normal servo?
I would like to make a more powerful servo, but need some advice on how to make it·like a normal servo.

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-15 04:23
    You can't "attach a pot" to the HB-25. It's not designed for that sort of use. Some other motor controllers have provisions for a position encoder. Here's one that uses a potentiometer: www.pololu.com/catalog/product/392.
  • moomoomoomoo Posts: 27
    edited 2008-07-15 04:31
    Thanks Mike,

    On the new gearmotor and wheel setup that parallax has, it uses an encoder. It doesn't attach to the HB25 or does it go to the microcontroller?

    Secondly, do you have any other refences to a higher amped controller with this feedback ability?
  • moomoomoomoo Posts: 27
    edited 2008-07-15 04:34
    I see Pololu has another higher amped one but doesn't say what max amps are.
  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-15 04:40
    1) The encoder is intended to go to the microcontroller or to some other encoder processor. There's existing code for the Propeller that uses one of its cogs to process this. Take a look in the Propeller Object Exchange.

    2) I don't what the max. current is. You might have to call Pololu to make sure.
  • moomoomoomoo Posts: 27
    edited 2008-07-15 04:46
    I really appreciate your help, Mike. You've at least steered me in the right direction (might be a bad pun in there somewhere) : )
  • randyazrandyaz Posts: 61
    edited 2008-07-27 21:08
    I used a QTI sensor with a BS2 for position sensing...

    http://spooksterville.com/site/index.php?option=com_content&task=view&id=16&Itemid=25
  • qdennisqdennis Posts: 5
    edited 2008-08-01 17:50
    The Cherry Corp AN8 rotary sensor works great for this.
    http://www.cherrycorp.com/english/sensors/an8.htm

    I am using the 360 model feeding into a 10 bit ADC which gives a range of about 104 to 912 spread over an entire rotation. Works great to make what is essentially a way big servo.
  • parskoparsko Posts: 501
    edited 2008-08-01 18:06
    Qdennis,

    Mind sharing where you got those, and for how much?

    Thanks,

    -Parsko
  • qdennisqdennis Posts: 5
    edited 2008-08-01 18:24
    www.Mouser.com has them in stock. These are mouser part numbers.
    sensor with rotary magnet about $33 : 540-CU103602
    the connector (you have to have this ~ $3) : 829-12162185
    crimp-on female parts - they call them terminals : 829-12124075

    It took me 3 orders to get all the parts. You are advised. These work great - you just have to read the analog signal.

    Quitman
Sign In or Register to comment.