Safety Shutoff Bumper on Electric Wheelchair

Friend has Parkinsons. 
I'm setting him up with electric wheelchair.
Best if he doesnt run it through walls, or run over anyone.

need electric shutoff on bumper front and back.
How, exactly?
and. Go.

Downunder35m9 months ago

Low tech:
Wire or strong cord on pillars connected to a switch.
Using flexible pillars like silicone or rubber would be prefered.
Works similar to these wire shut offs on big machines.
High tech:
Use parking sensors and set the alarm to a really short distance.
Once alarm is activated the corresponding gear is blocked and only the other direction will work - simple enough with two relays.