As part of my research at work, I was looking at laser diodes. They certainly have improved on these quite a bit lately. I was looking at 405nm BluRay burner diodes as a possible light source to locate brain tumors. Patients are given this stuff called ALA (5-Aminolevulinic acid) dye that selectively attaches to cancer cells, then 400nm light is used to excite the dye, which then glows red, making it visible to the surgeon. This way the surgeon can be sure to get it all out during surgery.
Anyway, in the process I ran across a bunch of more powerful diodes on eBay and decided to get one to play with.
I found a '70s era Weller soldering gun which I hollowed out and mounted the laser components into. Has sort of a '50s ray gun look.
Safety disclaimer: High powered lasers are very dangerous. Always wear proper protective glasses.
The diode module came with a lens and housing. The driver circuit is one of those cheap CC-CV simple switcher boards with adjustable current limiting. Laser diodes are like LEDs and need to run in constant current mode. The Weller gun came with a 2-stage trigger, so I modified the board for dual set points. The first stage on the trigger puts it into a low power aiming mode. This allows focusing and targeting at a relatively safe power (estimate around 50mW). Squeezing the trigger a little more, the second stage kicks in full power, which I have set at about 90% of the diode rating.
The lens has adjustable focusing. For close-up burn shots, you can focus closer and get much higher power density.
There is a key switch that locks out the power. I don't want my kids playing with this thing. I also don't want it going off in my pocket or backpack.
It runs off two 18650 Li-ion cells harvested from a used cardiac assist pump pack. The diode is running at about 1.5A, so I should be getting over an hour of burn time with these batteries. Below is a picture of the guts:
I measured the power output using a super-expensive power meter at work. I got around 1.6W. I might be able to push it to 2W, but I'd be risking blowing the diode. This is really impressive for a single diode of this size.
Here's a night shot going across my back yard:
The beam is really impressive in the dark. At closer range with the focus tight, it will burn wood instantly.
Here's a couple of YouTube videos: The first one starts out on low power, then switches to high power.
[youtube]wVFejhxKkcc[/youtube]
[youtube]qIv790sVubU[/youtube]
I've tried it out against various household insects. Ants are doomed. It's marginally effective against spiders. They can get out of the way fast enough to avoid cooking, but if I chase them long enough with the beam, I can eventually kill them. After a few of their legs get burned off, they slow down and are easier to hit. I have had zero success with anything that flies. I guess I need more power
Future possibilities would be to add some kind of beam stabilizer. Something like optical image stabilization used in cameras. The spot moves around quite a bit due to hand shake and spreads out the energy. If the spot could be stabilized, I could get a better burn. Some kind of optical sighting system would be useful as well. It's hard to aim before actually turning on the beam.
Anyway, in the process I ran across a bunch of more powerful diodes on eBay and decided to get one to play with.
I found a '70s era Weller soldering gun which I hollowed out and mounted the laser components into. Has sort of a '50s ray gun look.
Safety disclaimer: High powered lasers are very dangerous. Always wear proper protective glasses.
The diode module came with a lens and housing. The driver circuit is one of those cheap CC-CV simple switcher boards with adjustable current limiting. Laser diodes are like LEDs and need to run in constant current mode. The Weller gun came with a 2-stage trigger, so I modified the board for dual set points. The first stage on the trigger puts it into a low power aiming mode. This allows focusing and targeting at a relatively safe power (estimate around 50mW). Squeezing the trigger a little more, the second stage kicks in full power, which I have set at about 90% of the diode rating.
The lens has adjustable focusing. For close-up burn shots, you can focus closer and get much higher power density.
There is a key switch that locks out the power. I don't want my kids playing with this thing. I also don't want it going off in my pocket or backpack.
It runs off two 18650 Li-ion cells harvested from a used cardiac assist pump pack. The diode is running at about 1.5A, so I should be getting over an hour of burn time with these batteries. Below is a picture of the guts:
I measured the power output using a super-expensive power meter at work. I got around 1.6W. I might be able to push it to 2W, but I'd be risking blowing the diode. This is really impressive for a single diode of this size.
Here's a night shot going across my back yard:
The beam is really impressive in the dark. At closer range with the focus tight, it will burn wood instantly.
Here's a couple of YouTube videos: The first one starts out on low power, then switches to high power.
[youtube]wVFejhxKkcc[/youtube]
[youtube]qIv790sVubU[/youtube]
I've tried it out against various household insects. Ants are doomed. It's marginally effective against spiders. They can get out of the way fast enough to avoid cooking, but if I chase them long enough with the beam, I can eventually kill them. After a few of their legs get burned off, they slow down and are easier to hit. I have had zero success with anything that flies. I guess I need more power
Future possibilities would be to add some kind of beam stabilizer. Something like optical image stabilization used in cameras. The spot moves around quite a bit due to hand shake and spreads out the energy. If the spot could be stabilized, I could get a better burn. Some kind of optical sighting system would be useful as well. It's hard to aim before actually turning on the beam.