Vermes
Advanced Member level 4
This pointer of a significant power was made as an experiment. Its main element is laser diode from a broken DVD recorder from LG. On the internet you can find many constructions showing how to connect the diode to LM317. This solution is simple and working if you have a good source of voltage. Here a problem appears, if you want to make the portable laser pointer and powered from 2 Ni-MH accumulators. LM317 requires voltage not less than 5V for its proper work, which is too much.
Usually a driver for laser diode is op-amp application controlled using photo-diode. The diode from DVD recorder does not have a photo-diode, so it should be powered from a constant current source.
Any apply of electronic system before the laser diode results in voltage drops, so you cannot use 2,4V power (LD requires about 2,5V).
A simple and cheap system for supplying the laser diode from 2 accuulators were designed.
Below you can see the scheme and board:
The system can return maximum 160mA at the output.
Housing was made of aluminum.
Optics is a lens with focal length of about 2,5mm. It was pasted with an acrylic adhesive into the plastic plate. Lens distance from the work area of the diode is controlled using three small screws.
The spot of the laser is visible from a distance of 2km. In standard, after the concentration the laser melts black plastic, foil, lights matches etc. At night you can see the spot even on clouds.
Parameters:
- supply voltage: 2,3-4,2V
- current consumption: 380mA
- stability of output current in a function of supply voltage: 14mA/1V (do not change the type of supply)
- beam divergence: 12mrad
- wavelength: about 650nm
- beam power: 100mW max
WARNING!
Presented device is not a toy. There can be damage caused by improper use of the device. You risk temporary or permanent vision loss in direct eye contact. Do not direct the beam towards people, animals, work machines and vehicles.
Pictures:
Link to original thread (useful attachment) – Czerwony laser mocy, wskaźnik laserowy [Małe, a cieszy]
