Someone please tell me why do we need to pulse the IR transmitter. Why is there a need for signals and frequencies?
Three reasons:
1. There is a lot of dc background IR (e.g. from the sun, from incandescent lamps). So by using a frequency, you can use a frequency-selective filter to respond only when that frequency is detected. The frequency serves as a carrier frequency that you can modulate with the information of interest.
2. Different frequencies can be used to allow different IR devices to communicate without interference from each other.
3. And as Jake said, you need a frequency if you want to transmit more than just on or off.
You don’t have to use a 555. There are many other oscillators and microcontrollers that would work.
The whole point of an infrared transmitter is to transmit a signal. If you only provide a constant voltage to the transmitter then you aren’t transmitting any useful info. A 555 timer is a very common chip which is used to vary a signal as desired.
References :
Three reasons:
1. There is a lot of dc background IR (e.g. from the sun, from incandescent lamps). So by using a frequency, you can use a frequency-selective filter to respond only when that frequency is detected. The frequency serves as a carrier frequency that you can modulate with the information of interest.
2. Different frequencies can be used to allow different IR devices to communicate without interference from each other.
3. And as Jake said, you need a frequency if you want to transmit more than just on or off.
You don’t have to use a 555. There are many other oscillators and microcontrollers that would work.
References :
Pingback: Cander