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how does boe -bot return to original position? — Parallax Forums

how does boe -bot return to original position?

patrick van der Tolpatrick van der Tol Posts: 9
edited 2012-02-07 11:52 in BASIC Stamp
Hi,

ive got an problem, ive got a boe-bot with gripper kit. i want to program the bot that it picks up the closest object with the gripper kit and then return to its stat point with this object. The first part ive already programmed it drives through the closest object and picked it up, but how does it return?? im a newbie in programming.

thanks for the help.

patrick van der Tol

Comments

  • sylvie369sylvie369 Posts: 1,622
    edited 2012-02-01 03:47
    Short answer: you can retrace your steps, and come reasonably close. That is, if you went forward for 5 seconds, turned 90 degrees left, and went forward for 4 more seconds to reach the object, then you return by going backward for 4 seconds, turning 90 degrees right, and going backward another 5 seconds. Because of slippage (wheels against floor, for example) you won't wind up exactly where you started, but you should be in the ballpark.

    If you need to be more exact, you'll need some kind of sensors and a way of marking the starting point, and then some kind of routine for reading the sensors and adjusting if you're not there yet. That'd take a much longer answer.
  • patrick van der Tolpatrick van der Tol Posts: 9
    edited 2012-02-01 05:01
    thanks for the fast answer.
    i am using the ping sensor code to closest object. so its not possible for me to use a subroutine.
    is it in possible to place a flag or something in memory?
  • Just JeffJust Jeff Posts: 36
    edited 2012-02-07 09:40
    What about using some form of "beacon" like an IR LED that the Boe-Bot can look for and orient back to? (like roomba)
  • ercoerco Posts: 20,256
    edited 2012-02-07 11:14
    Just Jeff wrote: »
    What about using some form of "beacon" like an IR LED that the Boe-Bot can look for and orient back to? (like roomba)

    Kinda like...
  • Martin_HMartin_H Posts: 4,051
    edited 2012-02-07 11:36
    Beacons are an easy way to find your way back to an origin point. But if you don't want to do that dead reckoning is another possibility. The BOE Bot encoders can help do this:

    http://www.parallax.com/Store/Robots/RoboticAccessories/tabid/145/ProductID/80/List/0/Default.aspx?SortField=ProductName,ProductName

    This document takes a bit of time to read through, but is really instructive on using the encoders:

    http://www.parallax.com/Portals/0/Downloads/docs/prod/datast/ApplyEncoder.pdf
  • RL600RL600 Posts: 40
    edited 2012-02-07 11:52
    Maybe you can use a GPS. Before driving you can record the position in EEPROM.
    Then you go and pick up the object. And return to the position you get from the EEPROM.
    The only thing I don't know is the accuracy, so when the accurancy is 12 meter this won't work.
    But will be a nice project.

    RL600
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