More homebrew - Dual Diode setup

[stanwax]

Here are some images of my home brew dual red setup that I have constructed from as many nicked, pinched, or borrowed bits as possible.
http://photonlexicon.com/gallery/album72

It consists of a wirewound power resistor case with the resistor removed, the hole bored out to snugly fit a round diode module that has had its 3mW diode replaced with an open frame diode from a liteon x20 DVD burner.

The resistor case was cut in 2 after boring so that the diodes would be at the same height. The lenses in the modules were changed and fitted using my own turned mounting ring to ensure they located centrally. The diodes were tested and adjusted for beam before being put in the mount.

Then the pair were screwed to an ally baseplate using power semiconductor insulation pads from a dead PC ATX power supply. One diode was shone directly through a PBS also raped from a DVD drive - (an old one as these tend to have much larger cubes).

The cube is on a mount that allows a little adjustment in angle and a few mm back and forth to aid alignment. The other diode is shone at a mirror from a DVD burner - the one that fires the beam at the disc through the focussing assy, this is mounted on a 45 degree angle plate that has been made to have a little adjustment in 2 directions. This is the primary means of alignment for the pair.

Then the whole lot is screwed to a plate that is adjustable for hieght and the lot is fitted to the projector in an upright orientation to minimise the footprint.

The diodes are set to run at 300mA each and the whole lot measures 350mW on a lasercheck - we know this is not ideal and this subject has already been discussed at length so I dont want to this thread to go down the 'how accurate is a lasercheck at measuring diodes?' route.

Up to now I would guess the diodes have about 200hours on them and are showing no signs of death - but we will wait and see what life they get at this drive level. When running there is no sign of any heating to the case or the mount. They are driven by a simple driver board that has analogue modulation and is fed from a 5V SMPS.

Shortly I will be posting images of the entire projector and its assembly.

Hope its educational to at least one of you guys

Rob

[cruch]

wow..that was really nice

[chad]

That looks great! I need to get off of my butt and build my duel..

Chad

[sbk]

Nice machining

Looks like my dual setup (~480mW 660nm). Quite bigger but there is room for a 40x40mm Peltier cooler in the top...

[p1t8ull]

Very nice indeed.

Now start planning the quad - it's an addiction

[pixpop]

OK, very nice. I have more than enough parts to build a couple of these. Always wondered what I was going to do with all those power resistors.

Questions:
How did you remove the resistor from the heatsink?

How did you align the polarization of the LDs to match the PBS? Did you just manually rotate them until the intensity was maximum, or what?

[uk-laser]

I have used the same technique (emptied Al clad resistors) in the past.
My preference is for the slightly larger 50W types.
If you put 150W into a 2.2ohm 50W and have no heatsink the endcaps slowly jack themselves out before exploding (being restrained by a glowing nichrome spiral wire - like an angry slinky) Job for outdoors with a very long cable.
Any of the remaining grey insulation can be pressed out once the ceramic and nichrome bits have popped (and the whole thing left to cool)

[steve-o]

Ohh nice--
Blowing power resistors for the case by superheating them -ohh I wish i had thought of that -fcking awesome hehehehehe -verynice- I mean it
awesome

[Frank]

yes,so cool！

You can be one of my engineers,

[The_Doctor]

Agreed, that IS a very nice idea. If I'd thought of it I'd probably have used them. I might get a few to see what I can do with them. Square aluminium tubing is nice but it's not for everything. Actually I think I'd do it just to see an angry slinky.