Well I have finally made some time this winter to return to my lawn mower project… This has plagued me for a few years, trying to figure out the buried wire fence … Although I have certainly learned tons I by no means claim to know all about this buried wire fence… The circuit that I settled on after making so many that I can’t count and spending endless hours and money on different ideas… Sorry was going off on a rant there…

Anyway the circuit that is shown in the videos is a fairly simple 38Khz square wave being sent out onto the wire. and for a receiver I am using a L/C tank circuit and running that through a op-amp with adjustable gain and finally putting that signal through a peak detector circuit into an analog port on the Arduino… I will try and add a basic schematic/drawing of the circuit with the components labeled as time permits…

The first video is of lawnbott in random avoidance mode, the second is of wire following mode…

I will try and keep up on the progress as I complete but at the moment listed below is the sensors I have implemented:

  • buried wire fence detectors
  • right and left bumpers
  • battery level indicator
  • wheel encoders
  • mower blade motor encoder
  • mower blade motor current detector

Stay tuned…

autonomous lawn mower

  • CPU: Arduino Mega
  • Power source: 12v
  • Target environment: outdoor, Lawn

This is a companion discussion topic for the original entry at

I’ve been myself

I’ve been myself working (for a long time as well!) on a similar project (version 6 !) called La Poulette  with more details in french

This time I increased the burried wire frequency to 48 Khz, I thought I could get a more effective detection and It wotks well so I’ ll have to reduce the sensistivity.

Be aware that moving a robot on the lawn needs quite a lot of power and larger wheels.

I now working on an IR/US  docking station. To do that I’ve got to improve the accuracy of the steering mostly based on wheels-encoders (only 24 pulses/rotation) 

Drop the chassis

Really nice to see the progress - there are not enough robotic lawn mowers here (but then again, spinning blades etc…). Suggest lowering the chassis so the grass will stay within the robot and make it harder for kids / animals to get hurt. Spray paint it a nice color, add a sticker for your own “Brand” and model # and it will look like a commercial product! Also… easily accessible kill switch.