Design of a remote control detector

This detector can not only detect the quality of the remote control, but also check the waveform emitted by the remote control and detect the remote control receiver. With a little modification, it can also be used as a pulse oscilloscope, frequency meter, etc. This detector uses a computer for data processing and display.

The detector is divided into two parts: receiving and data processing. The receiving part uses a TNO2618 remote control receiver head (other models are also available) containing a CX20106A remote control receiver chip, which is connected to the LPT parallel printer interface of the computer (connect as shown in the figure). When the receiving head does not receive a signal from the remote control, the output pin is high level. When a signal is received, the level changes with the signal, forming a pulse square wave received by the computer and sending it to the data processing part. The data processing part is a program written in TurboC2.0 for data collection, processing and display. It should be noted that the base address of the LPT interface. A computer can have three LPT interfaces, with base addresses of 3BCH, 378H, and 278H respectively. The MSDEXE program of Windows 3.1 or DOS 6.22 can be used to view and determine the base address used by each interface. The base address of the LPT interface usually made on the motherboard is 378H. The program in this article is for demonstration, short and simple in function. Readers can freely rewrite it to make the interface friendly and powerful. According to this principle, adding an analog-to-digital converter to the circuit and writing the corresponding control program can turn it into a computer multimeter, oscilloscope, etc.

The program is as follows:

/＊This program is compiled and passed on TurboC2.0＊/
/＊Run on DOS7.0＊/
/＊2000613 WZW＊/

#include
＃include <graphics.h>
main()
{
int a,datain,datainoll;
int graphdrive,graphmode;
detectgraph(＆graphdrive,＆graphmode);/＊Detect the graphics card type＊/
if(graphdrive==VGA)
{
int mode=VGAHI;
initgraph(＆graphdrive,＆mode,"");
}
else
{
printf(" Graphics adapter not is VGA");/＊If it is not a VGA card, prompt and exit＊/
exit(1);
}
setcolor(13);/＊Set the color＊/
datainoll=inportb(0x378);
while(!kbhit())/＊Press any key to exit＊/
{
for(a=0;a<=599;a＋＋)
{
datain=inportb(0x378);/＊0x378 is the LPT interface address, which can be selected from 0x3bc, 0x378, 0x278 according to the machine configuration＊/
line(a＋20,datainoll,a＋21,datain);
datainoll=d
atain;
}
clearviewport();/＊Display waveform＊/
}
}