Could I replace a cheap laser pointer's LED with an infrared LED?

Yes you can but you will need to do some soldering though. Most laser pointer LED’s are soldered to a PCB (printed circuit board) and you can’t just tear it off. If you do this you will damage the PCB. You need to heat up both ends of the Laser LED to remove it. Once it is removed you need to clean the solder pads on the PCB with solder wick and circuit board cleaner. Now for the tricky part. You need to find an Infrared LED that will fit on the PCB and will work given the Voltage and Current requirements of the Infrared LED. Chances are they will not match up perfectly so you will need to find the right LED then figure out how you are going to make it fit to the PCB somehow. Good Luck!

Unfortunatly it would be very difficult. I’m guessing you would use a dollar store laser pointer. One thing is that laser pointers dont use LED’s, they use laser diodes which are fairly different. Not really important but it bugs me I’ve disected many laser pointers and discovered this: The loaser diode is connected to the circuit at one end, and the other contact touches the metal casing. The batteries touch the circuit at one end, and the other battery contact touched the metal casing as well. The housing for the laser diode is conductive plastic, and sandwiches the diode inside, touching the other lead, or it can hold the small lead in place just so it touches the metal casing. This makes it very difficult to put anytrhing else in a laser pointer casing because you will need to keep one contact touching the metal casing, and an LED is hard to do that with, you would end up building it and taking it apart several times because it moved, I’m sure.

Also, there is a small resistor in the circuit that would need to be removed, because an LED uses much more power that the laser diode that was in it originally.

It would be much easier to find a 3 volt button cell battery holder, and build a circuit with a switch, or build a joule thief and run it off of one AAA battery, then hide it in a marker or just glue everything together.

I personally would use a joule thief, it is a device which creates an electromagnetic field, boosting the voltage of any battery. Therfore, it keeps the LED running at maximum brightness for as long as possible, I used a half dead battery and a blue LED The most power hungry LED and it lasted for 4 days before it dimmed, and it lasted several days after that.

Either way if you build the circuit have a camera on hand to check that the circuit is working properly, as IR is not visible to humans.

This is just my advice, if you have any other questions feel free to ask.

Oh yeah, here is a good instructable for a joule thief