Arduino project

Raspberry project

Post Page Advertisement [Top]

One day, I got a Laser diode from broken DVD R/W player
By using classic way with resistor 4.7kOhm and 5V, I finally found the pole of laser and solder it

The next is driver circuit for Laser diode.
Normally, Laser diode will light at specified threshold current. Below threshold current, Laser diode will act as normal LED.

Searching around Internet, there is a simple way to drive current to Laser diode by using LM317. Unfortunately, LM317 is not in my hand. I only got 2N3055 transister which also can be used for drive current.

By adjust Vari-resistor from 47kOhm to 4Ohm, current through Laser diode is increasing.
At first, the Laser diode is lit as normal LED, when current increasing to its threshold, it is suddenly very bright

Install Laser diode back to lens set of DVD player, a laser light can go very far

In order to detect the current threshold, I use solar panel to sense light power

From here, easy to find suitable current to Laser Diode is only 55mA.


  1. wow ,im gonna try it and thanks ,is there a way to determine the poles of the diode leads

    1. In this case, cathode is ground, anode is another pin.
      For diode general, just try the diode in real circuit, if it not working -> change for reverse side.


Bottom Ad [Post Page]