Bump Sensors

It is time to add the bump sensors into the mix. Fortunately, the three microswitches and the curved fender are already in place so these can be wired up relatively quickly. I will use the arduino internal pull-up resistors so the switches will be active-low triggered.

The bump switches were wired in and the code changed to cater for them. Now the mower will continue mowing straight until it hits something, before turning to the reciprocal bearing. It became apparent that we need to back up a little to allow the front of the mower room to swing. All this kind of stuff can be fine tuned later so I am concentrating on getting simple functionality for now, enough to work. I did find however, that the poll period for obstructions of 1 second was too long. The mower is heavy and you know about it when it hits something. I have reduced this to 100ms for now to reduce the motor grind. It may need to come down further.

After some initial teething problems, this seems to work well although I am hoping the bump sensors will be a last resort as the mower is heavy and the forward drive is substantial. Now I have the basic idea, it is time to look at mounting an ultrasonic sonar so I don't batter the deck furniture to death! I need to make provision for side pointing sonars as well as I think these will be needed for mowing around obstacles.

May 2018