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Boe BS2 running a big AGV robot — Parallax Forums

Boe BS2 running a big AGV robot

Rural GeekRural Geek Posts: 17
edited 2012-10-25 16:19 in BASIC Stamp
Hi everyone.

I am just starting out with Boe Bot, which is great I am having fun with it but as usual I am thinking of bigger ideas. I have a stingray chassis, which is going to be the next step from the little bot. But I am going to use the 12v motors instead of the 7.2v, and the hb-25 motor controller. So what I am wondering is 1. where would I put the servo jumper vin or vdd? That all depends on the second question which is can I just run the BS2 off the 12v battery or should I use the AA battery hold that comes with the Boe Bot kit?

What I am trying to get to that I building as I go with the boe bot is a larger robot more of a 40lbs or so size agv to play with in my home. Now am I going to be able to use the BS2 as the micro controller? I am figuring that the Propeller would work better, I just would rather stick with one micro controller to start with. Unless there is a kit like the Boe bot for Propeller?

I know this is a big general question but any guidance would be great.

Thank you

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2012-10-25 12:44
    To try to answer some of your questions:

    1) The BOEBot is built around the Board of Education (BOE) which is a Stamp controller board. There is now a Propeller Board of Education which is intended as a mostly "drop in" replacement with extra features. You can buy the other parts that make up the BOEBot as a separate kit (the chassis, servo motors, battery holder, etc.) and combine that to make a Propeller BoeBot. I have such an arrangement sitting on the floor near me. It works well and there's a version of FemtoBasic (a simple integer Basic interpreter) for that which has some BoeBot-specific features (look at BoeBotBasic in the Propeller Object Exchange).

    2) You can certainly use the BS2 as a robot microcontroller for the larger robot.

    3) If you're going to use the HB-25 for your motor controller, it doesn't matter which jumper position you use (Vin or Vdd) since the HB-25 doesn't use power from the servo cable.

    4) You can use 12V for the BOE's Vin connection as long as you have very little else connected to the BOE (other than the HB-25s). The reason is that the voltage regulator has to dissipate the heat from the voltage drop from Vin to +5V. It does have a small heatsink which helps, but the regulator can supply up to 1A for the BOE and any sensors or LEDs or whatnot that's connected to it and, at Vin = 12V, it has to dissipate 7W of heat which will make the regulator quite hot. You'd be much better off using a switching regulator to drop most of the voltage from the 12V (actually 13.8V for a lead-acid battery). One possibility is this regulator which you can adjust for a 6V output.

    5) I'm biased towards using the Propeller BOE, but, if you're used to using PBasic and the BS2 BOE, you'll do fine and have a lot of fun.
  • Rural GeekRural Geek Posts: 17
    edited 2012-10-25 12:57
    Mike.

    Thanks for the great info.

    I saw the Prop BOE. I would like to use it cause of the sensors and line following I want to do with it. My question is does Parallax have a kit besides just the board to help me learn the Propeller language, that I can put on a christmas list?:lol: I am going to keep on working and learning the basic stamp also. But from what I see the Prop would be the better way to go for its features that I am going to be adding down the road.

    Thank you for that web site and the info on the regulator. when I go bigger I will use it. So what you are saying is if I use that regulator it will ease the regulation that the one on the BOE whill have to do, correct?
  • Mike GreenMike Green Posts: 23,101
    edited 2012-10-25 15:56
    If you want to go with the Prop BOE, you need to order two items ... the Prop BOE itself and the Bot kit.

    Yes, the switching regulator will reduce the amount of energy that the BOE regulator has to dissipate and it will do it in a way that will not generate a lot of heat itself (as a switching regulator).
  • Mike GreenMike Green Posts: 23,101
    edited 2012-10-25 16:01
    P.S. Unlike the BOE, the Prop BOE already has a switching regulator built into the board, so you wouldn't need the extra switching regulator. The Prop BOE will happily run off the 12V supply without generating a lot of heat.
  • Rural GeekRural Geek Posts: 17
    edited 2012-10-25 16:19
    Mike

    Thanks for all the help. It's been a lot of great information. If I have any other questions I'll just stop by the forum.
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