If you have got old laptop or DVD drive you can use laser diode to make laser pointer and in case that you have correct lens it can even burn small things.
You will need:
- old laptop or DVD drive
There are two laser diodes in laptops drives. One of them is InfraRed and is dedicated to burn CDs - the laser beam is invisible to human eyes and also dangerous. It can burn CDs and also human eyes.
The second one is red laser diode for burning DVDs. This is suitable for us, but again be very careful, it can damage your eyes.
The easiest option for laser construction is to leave diode in original mounting because there is also lens.
In case the laser diode is directly attached to battery it will burn out instantly. Always you have use resistor. In this case was used 9V battery so the minimum value of resistor is 36 Ohms (I used 2W resistor but stronger is better a will generate less heat). You can use more Ohms resistors, it also worked with 100 Ohms resistor and 9V battery. And you can use more voltage battery but then more Ohms resistor (for 12V recommend minimum 56 Ohms).
Plus pole of battery is connected to original mounting of laser because body of diode is + pole.
Resistor is on the minus pole of battery and which pin of diode is the correct one can be found by trying. Usually one of two middle pins.
Detailed tutorial and result you can find in this video:
This laser is also able to burn small things, but you have to use better lens.
However, Distance which laser can reach is great even with original lens.