Shop OBEX P1 Docs P2 Docs Learn Events
enhance the current for servos — Parallax Forums

enhance the current for servos

panagiotispanagiotis Posts: 14
edited 2006-03-21 15:45 in BASIC Stamp
I have constructed a robotic arm, and its element at the last DOF is a pair of electromagnets which i use in order to lift objects. The problem is that the electromagnets which i drive directly through the ports consume a great deal of current, so the·servos probably do not have an adequate amount of current to work efficiently and situations, like jerking·and loosing the desirable position appear, so how can i cope with this problem and if i must use some kind of external supply, how can i develop that technic. any help would be appreciated. thanks.··

Comments

  • allanlane5allanlane5 Posts: 3,815
    edited 2006-03-21 13:11
    Well, first of all, your title is kind of misleading. Your problem actually is 'browning out' the servos.

    Secondly, you probably shouldn't try to drive an electro-magnet's coils directly from an I/O port.

    Third, this situation is typically handled with an external "unregulated" 'wall-wart' power supply putting out 7.5 to 9 volts DC, which is then regulated with a 7805 or 2940-5 linear regulator. This will get you 1 to 1.5 amps, which usually is more than enough for several servo's.

    And if its not enough, you can power the servo's with their OWN wall-wart. Just make sure all the grounds of all the powersupplies are tied together.
  • neotericneoteric Posts: 144
    edited 2006-03-21 15:45
    I had the same problem.··My solution is to use the Parallax Servo Controller, which gives you the ability to power the servos seperately from everything else.· It also has some other features that come in handy when doing an arm.· At 39 bucks, its a steal.

    http://www.parallax.com/detail.asp?product_id=28023

    Post Edited (neoteric) : 3/21/2006 3:53:31 PM GMT
Sign In or Register to comment.