Wiltshire 24-key LED infrared remote control wrt-8032

Infrared remote control works many appliances are used infrared remote control, then what is the working principle of infrared remote control? First we look at what is infrared. The human eye can see visible light by wavelength from long to short order, followed by red, orange, yellow, green, cyan, blue, purple. Wherein the red wavelength range of 0.62 ~ 0.76μm; violet wavelength range of 0.38 ~ 0.46μm. Shorter wavelength than violet is called ultraviolet light, longer wavelength than red light called infrared. Infrared remote control signal is transmitted using near-infrared wavelengths between 0.76 ~ 1.5μm. Common infrared remote control system is generally divided into two parts for transmitting and receiving. The main element is an infrared-emitting portion of the light-emitting diodes. It is actually a special light emitting diode, because of its internal material different from the ordinary light emitting diodes, so when a certain voltage is applied to both ends thereof, it will be issued instead of visible light is infrared. Infrared wavelength infrared light-emitting diode emits currently widely used is about 940nm, shape and general 5 LEDs the same, just different colors. Infrared light-emitting diodes are generally black, dark blue, transparent three colors. Analyzing infrared light emitting diode bad way and judgment as an ordinary diode: look at the amount with a multimeter power block infrared light-emitting diode, the reverse resistance can be. Luminous efficiency of infrared light-emitting diodes use special equipment to precise determination, while amateur conditions can only pull a rough judgment from the law. Infrared receiving portion receiving tube is a photodiode. Give the infrared receiver diode is reverse biased, for it to work properly in practice, that the infrared receiver diode in the circuit is reversed using the application, in order to obtain a higher sensitivity. Infrared receiver diode generally circular and square. Since the transmission power of the infrared light-emitting diode is generally small (about 100mW), so that the infrared receiving diode of the received signal is relatively weak, it is necessary to increase the high-gain amplifier. A few years ago used μPC1373H, CX20106A and other special infrared receiver amplifier. In recent years, whether formal or amateur production of products, mostly using finished infrared receiver. Finished infrared receiver packages are basically two: one using metal shield; a plastic package. It has three pins, power supply positive (VDD), the power of negative (GND) and a data output (VO or OUT). Infrared receiver pinout vary due to different models, refer to the manufacturer's instructions. Finished advantage infrared receiver is that no complex debugging and Shell Shield, to use as a transistor, is very convenient. However, when using note finished the infrared receiver carrier frequency. Infrared remote common carrier frequency of 38kHz, 455kHz Taozhen which is used by the transmitting end to decide. On the transmit side of the crystal to be an integer divider, the division ratio of 12 general admission, so 455kHz ÷ 12≈37.9 kHz≈38kHz. There are also some remote system using 36kHz, 40kHz, 56kHz, etc., generally by the oscillation frequency of the transmitter oscillator to decide. Features infrared remote control does not affect the surrounding environment, do not interfere with other electrical equipment. Because it can not penetrate walls, so the home appliances in different rooms can use a common remote control without causing mutual interference;-circuit debugger as simple as pressing a given circuit connections, in general without any debugging can be put to work; codec easy, multi-channel remote control. As a result of manufacturers to produce a large number of infrared remote control ASIC, you need to find what you want. So now the infrared remote control in home appliances, indoor close (8-20 meters) remote control has been widely used. Infrared emission part of the multi-channel control infrared remote control multiple systems generally have a lot of buttons, representing different control functions. When the transmitter press a button, and correspondingly the receiving end has a different output state. The receiving side can be divided into pulse output state, level, self-locking, interlocking, five forms of data. "Pulse" output is the key when you press the transmitter, the receiver output terminal corresponding to an "effective pulse" width is generally around 100ms. "Level" means the output when the transmitter key is pressed, the receiver output terminals corresponding to the "effective level", when you release the key the transmitter, the receiver "effective level" disappears. By "effective pulse" and "effective level" may be high, it may be low, depending on the static condition corresponding output pin, such as static low, the "high" is effective; such as static high , the "low" is valid. In most cases, "high" as valid. "Self-locking" the transmitter output means every time you press a certain key, corresponding to the output of the receiver changes state, formerly high to low, the original low to high. Such output suitable for use as a power switch, mute control. This type of output is sometimes called "inverted." "Interlock" means a plurality of output Clear output each, at the same time there is only one output is active. TV channel selection in the case of such a case, other issues such as dimming, speed, audio input selection. "Data" refers to the number of transmit output key is assigned a number, use the receiving end of several output form a binary number to represent different key input. In general, in addition to several of the receiver output data, there should be a "data valid" output to the subsequent stage to fetch data in a timely manner. This type of output is generally used with a microcontroller or computer interface. In addition to these output format, as well as "latched" and "staging" forms. The so-called "latched" output signal of the transmitter means that each hair, the receiving end corresponding to the output to be "stored" until it receives a signal so far; "Scratch" outputs "level" the introduction of similar output. Factors ****** ****** remote control distance from the impact (Remote distance of RF Remote Control) of the main factors are as follows [1]: 1, transmit power: the emission power distance But power consumption, prone to interference; 2, receiving sensitivity: Receiver improve receiver sensitivity, remote control distance is increased, but susceptible to interference caused by malfunction or loss of control; 3, the antenna: The antenna straight and parallel to each other, remote control distance, but it occupies a large space, in use the antenna stretched, straightened to increase the remote distance; 4, H: the higher the antenna, remote control distance farther, but by the objective conditions; 5, a barrier: currently used wireless remote control uses state of the UHF band, its propagation characteristics and light approximation, linear propagation, diffraction is small, between the transmitter and the receiver, if the barrier wall will be greatly discounted remote distance, if it is reinforced concrete walls, due to the absorption of wave conductor, affecting even more.