Depending on the protocol and used channel a signal is send every 150 to 260 ms. (This reduces the possibility that signals overlap, when different remote controls are used at the same time on different channels). But the signal-to-signal distance is not important as long as there are no signals that might overlap.
Originally the signal is modulated at 38 kHz by the remote control, but the receiver works well within the band of 35 to 40 kHz. Our microcontroller uses a frequency of 38.4 kHz generated by the internal oscillator.
The different control factors are sent as binary numbers, with the most significant bit at first. In the following means “high” that the infrared LED is switched on and off at a frequency of approximately 38 kHz, “low” means that the LED is switched completely off.Print This Page