How to make an infrared detector for your PC

Enable your PC to receive infrared signals

How to make an infrared detector

We can always find an excuse to break out the soldering iron and play with a small pile of components.

A project that has been knocking around the internet for a few years is WinLIRC. It enables your PC to receive and transmit infrared signals with the right hardware. That 'right hardware' is something we can easily cobble together with an IR receiver and a few basic components.

Using WinLIRC you're able to monitor the IR signals and control your PC. The main limitation is that WinLIRC only works via a serial port or, alternatively, if your mobo has it through an Irda header.

We're going to first put together a basic serial connection for an IR receiver. Take a trip to the RS Components site at and pick up a 38KHz PNA4602M receiver.

The WinLIRC site offers a list of tested components at though it's a little outdated. As long as it's a three pin, 38/36KHz unit it should be work with most remotes.

You could connect this directly to the suitable serial port's pins: five for the ground, seven for the 5v power from the RTS line and pin 1 for the Data. However, it's advisable to add a suitable 5v regulator to the power line with the usual resistor, capacitor and a diode to guarantee a regulated supply.

You can actually make the IR receiver wires as long as you require, however we're going for the built-into-the-D-sub-hood effect and will use a 9-pin extension cable to position the receiver.

What you will need

38KHz IR receiver
4.7μF capacitor
1N4148 diode
4.7k Ohm resistor
78L05, 100mA, 5v regulator (TO-92 casing)
9-pin SUB-D socket and hood

How to make a detector

Step 1

1. What could we turn this pile of components into? Let's find out...

Step 2

2. This is the schematic, you can read this right? Oh, okay lets show you how to make this.

Step 3

3. The plan is to cram everything into the D-sub case, it'll have to be organised a little like this.

Step 4

4. To start, snip the right sides of the resistor, diode and capacitor to around 10mm. Solder the resistor to pin 1, capacitor to pin 5 and the negative diode leg to pin 7. This all fits into the thick end of the hood.

Step 5

5. Take the voltage regulator and identify the In, GND and Out connections each type can be different. Solder the middle GND to pin 5. Solder the 'in' to both the outputs of the diode and resistor. Solder the 'out' to the other capacitor's connection.

Step 6

6. Take two short runs of wire and solder these to pins 1 and 5.

Step 7

7. Solder the Data leg of the IR receiver to the pin-1 wire and the GND to the pin-5 wire.

Step 8

8. Finally, solder the middle Vcc leg of the IR receiver to the output of the voltage regulator and capacitor. Gently bend the components into place and it should all fit.

Step 9

9. The WinLIRC software will need to be configured for the correct COM port. You can click the 'RAW' button to view IR codes as they're received. Use the 'Learn' button to 'teach' WinLIRC the codes for a specific remote and assign buttons.

Step 10

10. Check the bottom of winlirc. page for a list of software that supports WinLIRC. The likes of Media Player Classic and BSPlayer do, snoop around the Options > Keys controls to enable the WinLIRC control.


First published in PC Format Issue 242

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