Engineer's Fun: Build a Super PC Remote Control for 20 Yuan

　　It is a DIY production of an infrared remote control audio source switcher and PC remote control with 4 stereo inputs and one output. Because it has a sound source switching function, it requires more components and the circuit is more complex, which is difficult for PCDIYers who generally lack electronic production experience. In fact, there are many PC infrared remote control solutions on foreign DIY websites. Some use PIC chips, some use digital circuits, and the simplest one only uses a receiver and a few voltage stabilizing components. Each of these many circuits has its own characteristics. Features, advantages and disadvantages. Today I will introduce to you a simple and easy-to-use PC infrared remote control. It uses very few components. It is easy to buy and the price is only about 20 yuan. It also has good scalability. Here is this A good article to introduce to the majority of DIYers.

　　The basic principle of the circuit is to collect infrared signals through the infrared receiver. When an infrared signal comes in, the microcontroller AT89C2051 software executes an interrupt and decodes the collected infrared signals, and sends them to the PC from the serial port. The PC software Girder receives the infrared signal from the serial port. characters and then make corresponding command operations according to the definition (for the basic usage of Girder, please see ). A few simple components are used in the circuit to make a serial port power stealing circuit, so that the remote control does not need an external power supply and can be used by plugging it into the serial port. It can be said to be plug and play :). After installation, after running Girder, the indicator LED1 will start flashing, indicating that the circuit is working normally. You can use your remote control at this time. When Girder is turned off, the power to the circuit board will be cut off and the indicator light will go out. The following is the production process and some specific precautions.

　　Figure 1 is the complete electrical schematic diagram of this remote control receiver. Please see Table 1 for specific components and parameters. Oh, these components are very common. You can buy them at the electronics market for only 20 yuan. Think about it, a PC remote control receiver on the market is not cheap. How can we, as DIYers, make such a difference? Why don’t you DIY it? Haha. Figure 2 is the appearance of the component.

　　Figure 1 Electrical schematic diagram

　　Table 1 Component List

　　Figure 2 Component Appearance

　　The DB9-pin serial port socket in Figure 2 is either male or female. It doesn’t matter. It just uses different connecting wires. No matter which one you use, you must clearly see the pin number when soldering the circuit ( There is a serial number on the socket), it will be bad if you make a mistake. Figure 3 is the pin diagram of the integrated infrared remote control receiver and triode 9012 in the component. It should be noted that the pin diagram of 9012 in the picture is just the pin polarity diagram of the 9012 I purchased. It may be the same as the one you purchased. The difference is that when installing it on the circuit board, first use a multimeter to measure the polarity of its pins to avoid accidental damage to the components. What? If you don’t know how to test, then you need to find relevant information to learn it, or ask a friend to do it for you, or let the merchant sue you when buying components. After collecting the components, we can start doing it.

　　Figure 3 Pin diagram of two important components

　　First, cut a suitable circuit board. Here I use a porous multi-purpose board. I usually use it when making small things. It is very convenient, but it is not so good if it is more complicated. Of course, if you have the conditions, you can process the printed circuit board yourself. Oh, I think this small DIY circuit does not need to process the printed circuit board. Generally, the universal boards purchased are relatively large. Here we can use a saw blade or a cutting knife to cut a circuit board of about 4cm*3cm (as shown in Figure 4). You can use sandpaper to modify the edge of the circuit board to make it smooth. After that, insert the components against the circuit diagram, solder, solder, solder! Oh, the serial port socket cannot be inserted? You can use needle-nose pliers to gently point it at the hole of the circuit board. Just bend the pins of the socket slightly and you can plug them in smoothly and solder them. Picture 5 is the soldered board. What you see here is that the circuit has been modified several times, and the solder joints are not very good: P. Picture 6 is the finished product before the AT89C2051 chip is plugged in. The next step is to program the microcontroller. If you don’t have a programmer, you have to pay someone else to burn it. There are services for burning chips in electronic markets or places that specialize in computer BIOS. Wait a minute, download this compiled microcontroller program first. ir.hex. Some remote control circuits do not use microcontrollers. Although these circuits are simple and easy to make, they cannot expand the function. The one I made now still has 12 function pins, which means it can also expand many functions, such as adding Relays can control the power supply of active speakers, displays, etc. or add corresponding circuits to control and monitor the speed of cooling fans in PCs, etc. However, these require modification of the microcontroller source program. After downloading and programming, insert the chip into the IC socket on the board and you are done. Remember to match the pin numbers and do not insert them in the opposite direction. See picture 7 for the finished product.

　　Figure 4 Cutting multi-hole universal circuit board

　　Figure 5: Soldered board

　　Figure 6: DIY remote control receiver without microcontroller plugged in

　　Figure 7 Completed picture

　　After that's done, let's look at the connection issues. If you use a female serial port socket on the board, you can directly buy a commonly used serial port communication cable, one with a male connector and the other with a female connector. I myself use existing joints on hand to make my own, which saves money. Because my circuit board uses a male serial port socket, I need two female wires to connect to the serial port on the PC. There are 9 wires on the serial communication line. Only 5 of them are included in this production. I used an 8-core network cable to connect wires 1 to 8 of the two female DB9 connectors one by one, that is to say, 1 to 1. ,2 to 2...8 to 8 connection (Figure 8). After connecting the cable, open the Girder software and set up the serial port (for the basic use and setting method of Girder, please refer to the author's "Building a Super PC Remote Control" published not long ago). At this time, there is power on the board and you can see the LED. Shiny, now you can control your PC as much as you like, isn't it cool? Figure 9 shows the remote control receiver at work.

　　Figure 8 Homemade serial port connection

　　Figure 9 DIY remote control receiver in use

　　When using Girder, if you want to define as many operations of different software in the same file as possible, you can define a return key to return to a list menu of the control software, and then define each numeric key to enter the corresponding software command group. Then close the menu, and then press the return key to close the software menu and enter the control list. It may be difficult to explain here. You can look at Figure 10 and download MyIR.GML (download at the end of this article) to see how it is specifically defined. My return key is the Recall on the remote control. The file only sets WINAMP and common system control functions. Press Recall first, then press 1 to open system control, press 2 to open WINAMP. After entering the function group, press Recall again if you want to switch function groups. Girder has many functions that are easy to use when combined. After a few attempts, you can use the remote control to play with your PC.

　　Figure 10 Girder defines functional operations