Infrared (IR) radiation is widely used in remote control devices to send signals wirelessly over short distances. Here’s how it works:
1. IR Light Emission
- The remote control contains an infrared LED that emits light in the near-infrared range (usually around 940 nanometers).
- This light is invisible to the human eye but detectable by IR sensors.
2. Signal Encoding
- When you press a button, the remote’s circuitry converts the command into a coded series of pulses (on/off flashes) of IR light.
- The pulse pattern represents specific instructions (e.g., volume up, channel change).
3. Transmission
- The IR light beam travels in a straight line to the target device.
- This is why most remotes need to be pointed toward the device — they use line-of-sight communication.
4. Reception and Decoding
- The device (TV, AC, etc.) has an IR receiver with a photodiode that detects the incoming pulses.
- The device’s microcontroller decodes the pattern and executes the command.
5. Advantages
- Low cost, simple technology, and no interference with radio signals.