Tactile sensors, in particular electric connection blocks, safety shutdown mats, buffers and electric switches activated by foot for safeguarding dangerous motions of machines as well as (automatic) gates, industrial vehicles and robots; tactile sensors, electric connection blocks and safety shutdown mats for security services; supersonic equipment, substantially consisting of a signal transducer/receiver and a signal evaluation processor unit, for obstacle detection as a safeguard on industrial trucks and for machine workplaces