Infrared remote control working principle

 post:2014-12-17

Generally, remote control system consists of the remote controller (transmitter), the receiver and the central processor (CPU) components. Receiver and CPU parts are in the appliance host. Remote control have different coded pulses, the pulse output various control signals to the infrared as a medium, these pulses are computer instruction code for controlling a central processing unit (CPU) operation. The receiver receives the infrared signal amplification, limiting, detection, after shaping to the CPU, CPU sends a control signal to the corresponding control circuit in accordance with different signal. Remote control include circuit, infrared -emitting portion and the key scan matrix of three parts: 

① control circuit is a core part of the remote control, we M34552 micro controllers, for example, the oscillator circuit shown in Figure, the crystal is connected to the microcontroller XIN/XOUT and XCIN/XCOUT pins to establish oscillation; oscillation circuit sent signal after shaping, division etc. Generate the control signal for scanning, to achieve infrared remote control on the output signal by the M34552 chip software functions.

② Infrared -emitting portion provided by the transistor power amplifier, a sufficient driving power infrared light emitting diode emits infrared pulse signals.

③ Key scan matrix by scanning output IC input circuit composed of horizontal and vertical cross- pinmatri no key is pressed, the input and output disconnected. When a key is pressed, the corresponding input signal that is served, the control circuit that which button is pressed, it will send a signal to control the functions specified.