The detected signal is coming out of the receiver at the other side. In the picture below you can see a modulated signal driving the IR LED of the transmitter on the left side. The IR receiver will be tuned to that frequency, so it can ignore everything else. With modulation we make the IR light source blink in a particular frequency. Therefore we have to take some precautions to guarantee that our IR message gets across to the receiver without errors.Modulation of the signal on a carrier frequency is the answer to make our signal stand out above the noise. ModulationĪs everything that radiates heat, also radiates Infra-Red light. When you read the OUT pin of the VS1838B with the wave from above, you will see something like the second. However, the point of the receiving device is to demodulate the signal and output a binary waveform that can be read by a microcontroller. This modulated signal is exactly what the receiving system sees.
If you were to hook an oscilloscope up to your TV remote’s IR LED, you would see a signal similar to the one above. When you hit a key on your remote, the transmitting IR LED will blink very quickly for a fraction of a second, transmitting encoded data to your appliance. 38kHz modulated IR data is the most common, but other frequencies can be used. There are very few natural sources that have the regularity of a 38kHz signal, so an IR transmitter sending data at that frequency would stand out among the ambient IR. A common modulation scheme for IR communication is something called 38kHz modulation. The sun is the brightest source of all, but there are many others, like: light bulbs, candles, central heating system, and even our body radiates Infra-Red light. We need to konw there are many more sources of Infra-Red light. Another reason is because IR LEDs are quite easy to make, and therefore can be very cheap, thus making it ideal for us hobbyists to use IR control for our own projects.
That’s one of the reasons why IR is chosen for remote control purposes, we want to use it but we’re not interested in seeing it. We humans can’t see this colour because its wave length of about 950nm is below the visible spectrum. Infra-Red light is actually normal light with a particular colour.
Then we will show how to use the micro bit with the IR controller to control the RGB module Parts Needed You will need the following parts: This tutorial will first explain the inner workings of common IR communication protocols. For example, when you hit a button on your TV remote, an IR LED repeatedly turns on and off, 38,000 time a second, to transmit information (like volume or channel control) to an IR photo sensor on your TV. This means IR is undetectable to the human eye – perfect for wireless communication. IR light is very similar to visible light, except that it has a slightlty longer wavelength. IR, or infrared, communication is a common, inexpensive, and easy to use wireless communication technology.