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!

 

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.

 

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.