Things I personally use:
-- my eyes
-- my smartphone
-- my garage door opener
-- my TV; also the TV remote
-- stove
-- microwave oven
-- toaster
-- night light
-- CD player
-- FM radio
-- car headlights
-- traffic stoplights
-- flashlight
-- telescope
-- binoculars
-- film camera
-- digital camera
-- GPS receiver
-- infrared thermometer
Things I don't personally use but are used by other people:
-- police radios
-- firemen's radios
-- EMT's ambulance radios
-- taxi drivers' radios
-- dentist's X-ray machine
