Remote slide show
Laser pen or sliding remote control

This kind of remote controller can be made by itself:

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Principle and maintenance of computer keyboard remote controller

The article was published in the 2008/3/23/004 edition of Electronic News.

I like watching movies on the computer, but computer control is not as convenient as TV, especially in winter, lying in the warm.

It is uncomfortable to operate the computer with a keyboard or mouse when getting out of bed, so I bought a keyboard remote control. pay attention to

It shows that this kind of remote controller is not a remote keyboard (also called wireless keyboard), but a remote controller used to control ordinary home computers.

The remote control accessory of wired keyboard based on can control the four keys of ordinary wired keyboard, such as F 1, F2, F3 and F4, which are mainly used for

Remote control operation of video on demand system.

Out of curiosity, the author disassembled and analyzed this remote control. The whole remote control accessory consists of two parts, one of which is a remote control operator.

The shape of the handle is similar to the remote control handle of the ordinary motorcycle burglar alarm, and the other part is the remote control receiving controller, 5cm.

×6cm small box, one PS/2 male and one PS/2 female.

First, the circuit principle

1. Remote control operation handle

This kind of remote control operating handle adopts a typical PT2262 coded remote controller, and the circuit is shown in figure 1. It uses integrated circuits.

PT2262 encodes the keying signal and can control four channels. In the figure, pins 1 ~ 8 of PT2262 are coded address terminals, each of which

The address terminal can be set to three states: high level (pin connected to 12V), low level (pin grounded) and floating, which can be used in combination with * * *.

There are 656 1 kinds of different address information, and 10 ~ 13 is the coded data input terminal D3 ~ D0, in which 4 bits of data are used, and each

A data terminal is connected with a key to control different devices. When any key is pressed, the voltage of 12V will be added to the key.

To the corresponding data terminal, at the same time, the voltage of 12V is applied to the power terminal pin of PT2262 through the diode, which is changed from VT 1.

The high-frequency oscillator also obtains the power supply voltage, and PT2262 will encode it according to the address code setting and input data, and output it from the pin.

Coding pulse, when the pin is pulse "1", the oscillator composed of VT 1 works to generate a high-frequency signal of 3 15MJHz, which is transmitted into the air.

When the pin output pulse is "0", the oscillator composed of VT 1 stops working, so the high-frequency signal is controlled by the encoding pulse.

Make.

2. Receiving controller

The receiving controller circuit connected to the host is shown in Figure 2, and the whole circuit is relatively simple. Pin PS/2 plug J 1 plug

The PS/2 keyboard socket behind the computer motherboard occupies the keyboard jack, so the receiving controller is equipped with a hole PS.

/2 socket J2, where the ordinary keyboard plug is now plugged. The receiver controller adopts high sensitivity 3 15MHz super regeneration.

Wireless receiving module, the circuit is shown in Figure 3.

Insert the pin plug J/KLOC-0 into the computer motherboard/get the +5V working power VCC of the receiving controller from the computer motherboard, and at the same time, this power supply

This power supply supplies power to the original ordinary wired keyboard through J2. The signal received by the antenna of the non-decoded super regenerative receiving module is amplified by VT 1 high frequency.

Input VT2 to select frequency, select 3 15MHz signal with the same frequency as the transmitter, and input IC 1A for amplification.

After the signal is shaped by IC 1B, it is output by Dout, restored to the same coded signal as the transmitter, and sent to the second point of IC 1 in Figure 2.

This pin performs decoding control, and the control signal is sent to the PS/2 keyboard interface through pins 6 and 7 of IC 1 in Figure 2. X 1, C4 and C5 are receiving.

The controller provides the working clock.

Pressing the four keys on the remote control is equivalent to pressing the four keys of F 1, F2, F3 and F4 on the computer keyboard.

The computer will perform the corresponding operation.

Second, the fault maintenance

The most common faults of this kind of remote controller are low sensitivity, individual key failure, remote control failure and so on. The following is the author's maintenance method.

Method:

1. Low sensitivity

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The main reason for the low sensitivity of the remote controller and the shortened control distance is that the battery voltage of the remote controller is too low. Usually, it is changed to

The new dedicated 12V battery can solve this problem. Sometimes the parameter change of the super regenerative receiving module inside the receiving controller will also lead to remote control.

Low sensitivity and shortened control distance. In this case, it is best to replace the entire super regenerative receiving module.

2. The single key is invalid

Because the keys on the remote control are pressed for a long time, the micro-key switch inside the keys is in poor contact, resulting in individual keys.

The main reason for the failure. This button switch is similar to the button on the front panel of color TV, and can be directly replaced by the short handle button switch of color TV.

3. Remote control failure

……