~100mW 650nm DIY DVD 'labby'

[Minousoft]

Just made my first DIY >5mW laser. It's 'labby' style, I don't have a casing for it yet. I used an Aixiz module, adjustable rckstr MicroDrive driver, and a HighTechDealz 650nm 16x Sony DVD diode, rated to go to 245mW. I'm not entirely sure if the MicroDrive is working properly, my new multimeter shows the current in the range of ~80mA-150mA with the test load, but I ordered the full range one. :-?

At its current current (?) setting, I would guess the diode to be outputting ~100mW but I have absolutely no idea. I put in 5.3v from 4 slightly used AAs.

I accidentally popped a balloon which was on my table, while the laser was on, and the current was turned down all the way & the laser was not focused properly.

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Comments and improvements are appreciated.

 

[daguin]

Just made my first DIY >5mW laser. It's 'labby' style, I don't have a casing for it yet. I used an Aixiz module, adjustable rckstr MicroDrive driver, and a HighTechDealz 650nm 16x Sony DVD diode, rated to go to 245mW. I'm not entirely sure if the MicroDrive is working properly, my new multimeter shows the current in the range of ~80mA-150mA with the test load, but I ordered the full range one. :-?

At its current current (?) setting, I would guess the diode to be outputting ~100mW but I have absolutely no idea. I put in 5.3v from 4 slightly used AAs.

I accidentally popped a balloon which was on my table, while the laser was on, and the current was turned down all the way & the laser was not focused properly.

Pictures will come soon! Comments and improvements are appreciated.

The "range" you quote sounds like you were measuring mA on the test load. On the test load, you have to measure voltage. The mV measured converts to mA input.

Peace,
dave

 

[Minousoft]

Yeah, thats what I did, I put my multimeter leads across the large resistor, set to the 200mV range, and the readings changed from ~80mV to 100-something mV using the adjustable pot/cap thing. 80mV = 80mA

 

[Minousoft]

I cranked up the pot in increments all the way, with the diode showing no damage signs. The diode smoked some plastic but started heating up, I think that may have reduced the output, so I stopped.

I also added some pictures to the main post.

Pretty cool.

 

[daguin]

I cranked up the pot in increments all the way, with the diode showing no damage signs. The diode smoked some plastic but started heating up, I think that may have reduced the output, so I stopped.

I also added some pictures to the main post.

Pretty cool.

Pretty cool, indeed.

Peace,
dave

 

[pseudolobster]

Nice job!

I'll point out though, that most people reserve the word "labby" to refer to a laser that's rated for continuous output or "CW"... usually involves massive heatsinks or peltier TECs (thermoelectric coolers).

That's odd though, that you'd only be able to get 150mA out of the driver... You may want to talk to rkcstr about that or at least measure the resistance across the potentiometer to see if your driver is in spec and perhaps your multimeter is screwy.

 

[Minousoft]

@pseudolobster
I was thinking about getting a TE module and a CPU fan, and making sort of a heatsink sandwich, with the LD taped to the top or something like that. It would probably work better with thermal grease, or Arctic Silver.

 

[FireMyLaser]

This setup works great for heatsinking and it's simple. I power a red at 150 CW no problem for hours at a time, it didn't ever get hot. It died at 200mA, but the diode was unknown so maybe I pushed it too far. It worked for 3-4 hours constant at 200mA and was still cool, it just poped.

And it's super easy to add a fan.

Or you can do this, just add more mass than I did:
http://www.laserpointerforums.com/forums/YaBB.pl?num=1216229362
It takes allot more work, but it also looks much better IMO.

 

[IgorT]

At its current current (?) setting, I would guess the diode to be outputting ~100mW but I have absolutely no idea. I put in 5.3v from 4 slightly used AAs.

You're not giving the driver enough voltage. It's possible (or even likelly), that the current does not go to full current, because the driver is not regulating properly. 5.3V is at the edge, or below what the driver needs to regulate the current.

Rkcstr's driver needs at least 2.5V MORE, than what the diode needs. The diode needs roughly 3V. So your minimum voltage should be 5.5V. And when i say minimum voltage, i mean when the batteries are empty.

You could get away with five alkalines, but i'm thinking you might want to switch to Ni-MHs eventually, in which case you need 6. Or two Li-Ions. In both cases, the full voltage will be 8.4V and the empty voltage will be 6V, and this will mean, that your current will stay the same all the time, and not depend on the batteries.



But, if this should be the case, and you now put two more batteries in, you need to REDUCE the current first, and then set it to where you want it again. You should set it on the dummy load, not the diode.

This is important, because if the driver is not regulating now, you don't know what it's actually set to. After giving it enough voltage, it would suddenly start regulating again, and the current will jump to what it is set to - which you don't know.



Otherwise, if you tell me what it says on the two resistors around the pot, i can tell you, what range it is.

 

[IgorT]

Comments and improvements are appreciated.

Oh, and you should solder the driver to the diode directly.. The way it is designed, it fits between it's legs perfectly. And soldered to all three, it makes it hard for them to break off.

It's safer, and more proffesional, as well as takes up less space.

 

[styropyro]

[quote author=Oakwhiz link=1216438970/0#0 date=1216438970]Comments and improvements are appreciated.

Oh, and you should solder the driver to the diode directly.. The way it is designed, it fits between it's legs perfectly. And soldered to all three, it makes it hard for them to break off.

It's safer, and more proffesional, as well as takes up less space. [/quote]
Agreed. When the driver is soldered right to the diode the whole setup feels stronger. Nice build by the way!

 

[Minousoft]

Thanks everyone. I checked the resistors with a chart that rckstr made, and they check out properly. I switched to a big 6v Duracell lantern battery, but I might change this to a rechargable bank as IgorT said.