A remote control is a component of an electronics device, most commonly a television set, used for operating device wireless from a short line-of-sight distance.
If you want to know whether the function of an infra red remote control (TV, air conditioning, etc.), is Ok / the battery is still good or is weak, take your digital camera, or you can also use hand phone camera.
Switch on the camera, press and hold one of buttons of the remote control, use the camera to see infrared light of the remote control.

 Look at the camera monitor, if the remote is in good condition, then the light from the infrared remote control will be seen brightly on the camera screen.
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