Wireless transmission and reception of door - controlled signal
Column:Access control Time:2018-05-10
The control panel of the remote control has A, B, C and D control keys and A transmitting indicator light. Transmitter inside adopt import table stable resonator frequency, frequency consistency is very good

The control panel of the remote control has A, B, C and D control keys and A transmitting indicator light. Transmitter inside adopt import table stable resonator frequency, frequency consistency is very good, very high degree of stability, working frequency 315 MHZ frequency stability is better than that of 10 to 5, don't need to adjust the frequency point in use, especially suitable for multiple wireless remote control system using a closed, etc, and the wireless remote control module on the market at present is still commonly use LC oscillator, poor stability and consistency, even with high quality fine-tuning capacitor, temperature change and vibration frequency is difficult to guarantee has been debugged point does not happen, caused by distance.

The receiving module is produced by SMD lamination process. It is a super-regenerative receiving method.

1. The input end of the antenna has a frequency selection circuit, which does not depend on the frequency selection of 1/4 wavelength antenna. When the control distance is close, the antenna can be cut short or even removed

2. The radiation of the receiving circuit itself is minimal, and the shielding effect of the reticulated ground copper foil on the back of the circuit module can reduce the leakage of its own oscillation and the intrusion of external interference signals.

3. Receiver with high precision copper core inductance with skeleton adjust the frequency to 315 m after cementing, this with the adjustable capacitance compared to receive frequency adjustment circuit, temperature, humidity stability and mechanical vibration resistance are improved greatly. Adjustable capacitance adjustment accuracy is low, only 3/4 laps of adjustment range, and adjustable inductors can achieve multi-laps adjustment. The adjustable capacitance cannot be sealed after the adjustment is completed, because the proximity or invasion of various media will change the capacity of the capacitor, which will affect the receiving frequency, no matter the conductor or the insulator. In addition, the unsealed adjustable capacitance has a displacement between the stator and the rotor when subjected to vibration. When temperature changes, thermal expansion and cold shrinkage will change the distance between fixed and moving plates. Changes in humidity due to changes in media capacity; Will also work for a long time in moist environment due to the change of oxidation and dynamic pills capacity, these will seriously influence the stability of the receive frequency, and adopts adjustable inductance can solve these problems, because after the inductance can be adjusted for cementing, insulator cementing agent doesn't make the inductance changes, and because the SMT process, so even a strong vibration also don't have to worry about receiving frequency drift, about 500 KHZ, the receiving circuit to receive bandwidth product factory has adjust center frequency at 315 MHZ, receiving chip fine-tuning about 5 MHZ frequency range of adjustable inductance, don't change when using, To avoid affecting performance.

Seven terminal receiving module, respectively VCC, GND, D1, D2, D3, D4 and VT, with VCC for 5 v power supply side, the GND for earthing terminal, VT end for decoding effective output end, from D1 to D4 four data latch output, can output high level 4 v, drive current 2 ma, and transmitters on the A, B, C, D four for A ZongJian corresponds.

This is the transmitter equivalent circuit diagram

This is the equivalent circuit diagram and application of the superregenerative receiver

Working principle:

PT2262 and PT2272 are city Taiwan company produces a pair of COMS special coding circuit, oscillation frequency adjusted by an external resistors, chip PT2262 encoding signal coding by: address code, data, synchronization code to form a complete code word, after decoding chip PT2272 receives the signal, its address code after two comparison, after checking VT feet to output high level, at the same time the corresponding data foot also output high level, if the sender has been holding the keys, encoding chip will continuously launch. When there is no buttons to press the transmitter, PT2262 is not connected to the power supply, its 17 feet is low level, so the high frequency of 315 MHZ transmission circuit doesn't work, when there is a button press, PT2262 electric work, the 17 feet by the modulation of the serial data output signal, when 17 feet for high level during the high frequency of 315 MHZ launch circuit vibration and continuous high frequency signal, when 17 feet for low during the high frequency of 315 MHZ transmission circuit to stop oscillation, so high frequency transmission circuit completely closed in PT2262 17 feet output digital signal, Thus, the completion of amplitude keying (ASK modulation) for high frequency circuits is equivalent to 100% amplitude modulation.

Coding circuit PT2262 and PT2272 1 ~ 8 feet set foot for the address, can choose impending, three kinds of states are power supply, grounding, 3 of 8 power is 6561, so don't address code duplication of 6561 set, only PT2262 and PT2272 address coding are exactly the same, to match, the manufacturer to facilitate the management, the factory PT2262 and PT2272 eight address coding end all choose impending, if users want to change the address code, as long as PT2262 and PT2272 1 ~ 8 feet set can be the same, For example the transmitter PT2262 1 feet grounded 5 feet is power, other pins impending, then the receiver PT2272 as long as 1 foot also ground 5 feet is power, other pins dangling can achieve matching to receive. When the two address codes are exactly the same, the corresponding D1 ~ D4 terminal of the receiver outputs about 4V interlock high level control signal, and the VT terminal also outputs decoding effective high level signal. These signals can be amplified by the user to drive the relay, power transistor and other load remote control switch control.

PT2262/PT2272 chip usage data

How to change the address code of the remote control:

Here provide remote control coding and decoding chip PT2262 and PT2272 (or SC2262, SC2272 both fully compatible), it's 1 ~ 8 feet set foot for address, factory in order to facilitate production management, factory are set in dangling position, if in be used actually mix more sets of remote control, and don't want to interfere with each other, then for different number of remote control to set different address codes. Encoding and decoding chip can choose the address of the foot: suspended three power supply, grounding, is so not to repeat the probability of maximum 8 power for 6561 to 3, so don't address code duplication is 6561 group, as long as PT2262 and PT2272 1 ~ 8 feet set the state of the same pair remote-controlled transceiver can be realized, and different address of the remote control will not interfere with each other. Such as the one set of transmitter PT2262 1 foot of ground, 5 feet is power, other pins impending, then the receiver PT2272 as long as 1 foot also ground 5 feet is power, other pins dangling can achieve matching to receive.

Application, for example,

1. The method of making a single lock remote control switch

Purpose: for remote control of an alarm circuit on and off, or a lamp on and off

Usage: press the "A" button of the remote control, the power of the alarm circuit is on or A lamp is on. When the button is released, it is still on or on. Only when either of the B, C, or D buttons of the remote control are pressed, the power of the alarm circuit is turned off or a lamp is turned off. When the button is released, it is still closed or closed

The receiver of the remote control circuit consumes only 4 milliamps of electricity in the waiting state, which is very energy saving. It is suitable for some circuits with battery power supply or high power consumption requirements.

2. The method of making non-lock type point operated four-way remote control switch:

Control purpose: some need to move the remote control of the situation, most can realize four road, such as remote control electric gate opened and closed, some with light touch switch control occasions, such as home appliances on the volume increase, reduce the key channel, increase, decrease.