/diy/ - Do It Yourself

>>1306513
That's pretty solvable if you plop a touch sensor out in front of the blade at it's vertical level, with a little bit of force keeping it in the unpressed position. Grass wouldn't be enough to trigger it but anything solid would.

Pic related, blue = blade, orange = microswitch, purple = rock detector.

An actual good arduino //programming// project would be a little mini-robot that you could get your software running on indoors, and throw a bunch of obstacles at to make sure your programming would do good obstacle avoidance before you throw it on a motorized death machine that would cost money every time it hits something and breaks the blade.