At present I am working on a Motorised Wheelchair Base unit using the original Motors,these are pretty powerful and can inflict a lot of damage if great care is not taken.
Using my EZ-B to control its movement ,although it operates quit well, but for example if I loose connection for any reason the Robot can now be a monster out of control.
To provide a safety feature to remove power from the motors one could use a micro switch on front & rear and once it meets an object it will stop.
Good idea ,small problem it may be travelling at speed and you could sustain a serious injury if you happen to be that object.
My solution under construction at present, is use a Car Parking Radar which is stand alone and is not dependent on Ez-b or pc connection .
To put it simply if an object is say within 10 ins of Robot ,power is cut off to motors. Then it can be reset through EZ-B if necessary
link to unit