The original post: /r/lifeprotips by /u/virusofthemind on 2024-12-03 20:54:19.

Most remote controls use an infrared LED to transmit information from the handset to the device they control. Although invisible to the naked eye it’s just at the cusp of what your phone camera can detect and process. If you point your phone camera at the LED and press any button on the device you will see a faint flickering blue-violet light as the handset transmits. If not; you need new batteries.