Wire Length Considerations

Discussion in 'General Electronics Chat' started by Pidgeydoyle, Apr 7, 2013.

  1. Pidgeydoyle

    Thread Starter New Member

    Dec 4, 2012
    I am considering modifying an old push mower into an inductively guided robomower for my large back lawn (0.5 acre).

    I currently have a commercial robotic mower in use in another lawn, its pretty good but has too small a blade for the big lawn and it mows in a random pattern which is sort of wasteful and is pretty ineffective on a big lawn.

    My plan is to lay a wire just below the grass in a up down pattern and allow my bot to follow it verbatim.

    The wire will emit a high frequency magnetic field which will be received by the robot and can follow it.

    I have a few questions.

    1) Since i want my mower to follow the wire. the wire will have to be very long (150m+), what will i have to consider when driving the signal in this regard do you think? (wire inductance could be high)
    2) Any suggestions on generating the signal I might not have considered especially for such a long wire?
    3) I plan on negotiating the wire by comparing the voltage entering the analogue pins of a microcontroller coming from an inductor/amp circuit. any overall tips would be super!
  2. takao21203

    AAC Fanatic!

    Apr 28, 2012
    Too much effort to work this out.

    You can use the wheels rotation to compute distance, and program a pattern of movement.

    Any decent controller board can do this.

    The STM32 demo board has a compass module already. So you could use that as well.

    And add a touch screen GLCD to program the movement pattern.
  3. Pidgeydoyle

    Thread Starter New Member

    Dec 4, 2012
    The main reason im concerned about the wire length is that the signal strength would diminish with distance. I dont mind if the robot drives on forever that should be easily fixed.