Shop OBEX P1 Docs P2 Docs Learn Events
extra power for boe-bot servos — Parallax Forums

extra power for boe-bot servos

vla7vla7 Posts: 79
edited 2008-12-21 18:53 in BASIC Stamp
I want to provide a separate power source to·my servos on the boe-bot.· I see that there is a jumper between the X4 and X5 servo connections.· If I decide to add a 6 volt supply to just power the servos, would I connect the positive wire to Vin of the jumper and would·I connect·ground·Vss on my board?

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2008-12-21 03:29
    Look at the schematic for the Board of Education (www.parallax.com/Portals/0/Downloads/docs/prod/boards/BOERevC.pdf). If you want to use the same supply to power the Stamp (through the on-board regulator), you'd plug your 6V supply into the power socket on the BOE and set the jumper to connect the servos to Vin which would be the 6V. If you want to use a supply separate from the Stamp, you'd need to connect the +6V to the center pin of the jumper pin-block as you can see on the schematic and the -6V wire to Vss on the BOE. Be very careful that you don't accidently connect the +6V to either the Vdd pin or the Vin pin if you don't use the jumper as intended.
  • vla7vla7 Posts: 79
    edited 2008-12-21 04:21
    Ok, so I can connect the +6 to the center pin of the jumber and the -6V to Vss and can use this to power my servos. Would I then have to use a 9V to power my stamp. Currently I power my stamp and the servos from a 6V battery pack (4 1.5 AA volt batteries) that connects to the power jack and the jumper is connected to Vdd. Can I continue to use this battery pack connected to the power jack to power my stamp and just supply another battery pack for my servos?
  • Mike GreenMike Green Posts: 23,101
    edited 2008-12-21 05:22
    You have to decide what you want. You can plug a larger battery pack (at 6V) into the power jack and set the jumper to Vin or you can continue to use the 6V AA battery pack to power the Stamp and use a larger 6V battery pack to power the servos only or you can use a 9V supply to power the Stamp and a different (6V) battery pack for the servos.

    If it were me, I'd just use a larger 6V battery pack to power everything through the power jack. If you have two separate supplies, you also need a switch for the second supply.
  • vla7vla7 Posts: 79
    edited 2008-12-21 05:40
    Well, I'd like to get more speed from my servos and since they can handle 6 volts, I'd like to give them six. As I understand, the regulated volt on the boe-bot will only give them 5 volts. If I simply move the jumper to Vin, will it send the regulated 5 volts to the stamp but not regulate the voltage going into the servos so that I get more voltage to the servos?
  • UghaUgha Posts: 543
    edited 2008-12-21 18:53
    Your correct. If you move the jumper to VIN then you'll give the servos whatever voltage you've got connected to the BOE.
    for 4 AAs that'd be 6 volts.

    Make sure that you do not use a 9volt battery if you choose to do this. The servos can't handle 9 volts. I THINK they are
    rated for 7.2 volt max, but don't hold me to it.

    If you want to completely isolate the servo power from the BS2 then don't use the jumper at all. Connect your own
    wire to the center pin of the jumper and then connect it to the + on your battery pack and connect the - of the pack to
    VSS on the BOE.

    As Mike said, its vital not to connect your battery pack to VDD or VIN on the BOE. This includes accidently touching it against
    the top or bottom pin of the jumper.

    You can then use a 9volt or 4xAA battery pack to power the BOE as normal.
Sign In or Register to comment.