Shop OBEX P1 Docs P2 Docs Learn Events
Hacked servo for more power. — Parallax Forums

Hacked servo for more power.

GrampsGramps Posts: 117
edited 2010-07-09 01:28 in General Discussion
Hacked servo for more power.
Modify a standard servo by cutting the stop out of the gear box to make it continuous running.
Remove the pot from the servo and reconnect with 6 inch wires.
Connect the servo to a threaded shaft and move heavy stuff at much slower speed but with more torque.
Connect the pot to a lever on the threaded shaft for feed back.




Gramps

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
'What is your life?"
"It is even a vapor that appears for a
little time and then vanishes away."
Saint James 61 A.D.
IMG_1244.JPG
2816 x 2112 - 2M

Comments

  • ercoerco Posts: 20,260
    edited 2010-07-08 16:16
    Sweet, Gramps! Try a linear sliding pot of the right value in-line with your leadscrew.

    Use LOTS of lubricant. Dry leadscrews (especially allthread) have tons of friction and will cut your useful load in half. Also, make sure your applied load is in-line with your leadscrew and doesn't twist your threaded follower. Any binding of the follower is suicide!

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    ·"If you build it, they will come."
  • GrampsGramps Posts: 117
    edited 2010-07-08 16:38
    You're right! This is a 2.5 inch high grade bolt with a metric head, driven by a 11 mm socket JB welded to the servo. We need an inch and a half total movement.

    Do you have a source for 5k slider pots?

    Or could a 100k pot (i have 5 ) be converted to 5 k?
    I'm thinking a Wheatstone bridge would work........

    Actually the cables coming from my robot fingers tie to this ground bar shown in the photo, which has to rotate 90 degrees either side of center when the wrist turns, so we're hoping we can keep everything in alignment.

    Gramps

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'What is your life?"
    "It is even a vapor that appears for a
    little time and then vanishes away."
    Saint James 61 A.D.
  • Spiral_72Spiral_72 Posts: 791
    edited 2010-07-08 19:53
    If you add a 5263.15789474 ohm resistor in parallel with the 100k pot, it magically becomes a 5k pot!!

    hehehe [noparse]:)[/noparse]

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "puff"...... Smile, there went another one.
  • Spiral_72Spiral_72 Posts: 791
    edited 2010-07-08 19:56
    That's a pretty neat idea too by the way! I saw a guy made a CNC out of RC servos. I bet this is just about how it worked too. I always wondered about that. I wish I still had a link to it. The link died with my hard drive [noparse]:([/noparse]

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "puff"...... Smile, there went another one.
  • GrampsGramps Posts: 117
    edited 2010-07-08 20:03
    We have another app. where we will mount a small gear on the servo head and it will link with a much larger gear. same effect. Feedback pot connected to the big gear.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'What is your life?"
    "It is even a vapor that appears for a
    little time and then vanishes away."
    Saint James 61 A.D.
  • ercoerco Posts: 20,260
    edited 2010-07-08 20:09
    That would make a very non-linear pot... unsuitable for a servo.

    Will look for 5K sliders.... that's the right way to do it.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    ·"If you build it, they will come."
  • GrampsGramps Posts: 117
    edited 2010-07-08 20:17
    That's what i thought.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'What is your life?"
    "It is even a vapor that appears for a
    little time and then vanishes away."
    Saint James 61 A.D.
  • ercoerco Posts: 20,260
    edited 2010-07-08 20:48
    http://www.mouser.com/search/ProductDetail.aspx?qs=8YYpzd7qSxKID6GqcS4NQA==

    http://www.mouser.com/search/ProductDetail.aspx?qs=8YYpzd7qSxKID6GqcS4NQA==

    $1.65, not bad!

    Have to copy & paste·that link WITH the == on the end, it didn't hyperlink properly here

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    ·"If you build it, they will come."
  • GrampsGramps Posts: 117
    edited 2010-07-08 20:59
    what's the part number?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'What is your life?"
    "It is even a vapor that appears for a
    little time and then vanishes away."
    Saint James 61 A.D.
  • GrampsGramps Posts: 117
    edited 2010-07-08 21:01
    all i see is a 20k for $11

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'What is your life?"
    "It is even a vapor that appears for a
    little time and then vanishes away."
    Saint James 61 A.D.
  • ercoerco Posts: 20,260
    edited 2010-07-08 21:49
    attachment.php?attachmentid=74100

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    ·"If you build it, they will come."
    p921090-1.gif
    513 x 164 - 7K
  • GrampsGramps Posts: 117
    edited 2010-07-08 22:40
    @erco, thanks!


    I don't see a minimum order, is it listed someplace? $25?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'What is your life?"
    "It is even a vapor that appears for a
    little time and then vanishes away."
    Saint James 61 A.D.

    Post Edited (Gramps) : 7/8/2010 10:47:27 PM GMT
  • W9GFOW9GFO Posts: 4,010
    edited 2010-07-08 23:28
    Minimum is 1;

    www.mouser.com/ProductDetail/Alpha-Taiwan/RA2043F-20-10EB1-A5K/?qs=8YYpzd7qSxKID6GqcS4NQA%3d%3d

    Rich H

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Simple Servo Tester, a kit from Gadget Gangster.
  • GrampsGramps Posts: 117
    edited 2010-07-09 01:28
    Ordered 4, thanks for the walk through!


    Gramps

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'What is your life?"
    "It is even a vapor that appears for a
    little time and then vanishes away."
    Saint James 61 A.D.
Sign In or Register to comment.