[Not Yet Finished] R+G Yellow Laser

Hey all, I figured since I'll be waiting a few weeks for my green modules to come in and my friend and I to meet up so he can give me his broken DVD Burner, I'd start a thread about this build I've been planning. Maybe you can all help me out with tips and ideas

I am not aiming to build a burning yellow laser, but if it ends up being able to do so, that's a plus! The way I'm going to determine power is all based upon the green modules power. I ordered some cheap NewWish style pens today and will use the most powerful one's module and then assemble a red module approximately 4 times the strength of it to get a good mix. I am probably going to use a Groove2 for it so I can adjust the output, via the pot, so the colors are in a good ratio. My original goal was to have a 50mW green with a 200mW red, but I doubt the NewWish Pens will be close to that so at best it will be 30mW:120mW, but I'm not going to be crushed if its lower than that

So I've wanted to build a yellow laser for a long time now. Someone wanted me to build them a PHR-803 laser and I figured, "Why let the optics go to waste" and took them out. I remembered hearing about how Jayrob used them to make a yellow pointer.



Anyway I really like using aluminum boxes for laser hosts. They're just so shiny and cool looking. So I picked up some parts at RadioShack for the "non-laser" part of the build. This is what I have so far...



I'm going to use these two toggle switches to choose what colors are being put out by this laser set up. They will obviously be wired with their corresponding light color to indicate what color is being "lased". Yes I know the LED's are a tad off center and it does bug me, haha, but oh well it's always something! You'll notice there is an audio jack and plug which, you guessed it, is an incorporated safety key. Mainly for peace of mind so I don't have to worry leaving it in my room when people who don't fully appreciate the work and safety practices we all put into these are around.

Also there is an empty hole! But that just needs to be filed out a little bit to fit my DC Jack I'm going to use. I don't yet know if I want to run it off of a 9V supply or Li-ions yet, but this option lets me choose later on

So that's the externals... Here is an MS Paint diagram of where I am going to put the actual lasers.



Pretty basic, but I felt like MS-ing something!

Anyway I would like to know any suggestions or ideas anyone has to help me on this.

Here are some build tips I've sort of come up with that I'll try to use for the construction and actual alignment.

- Use fog to help align the beam
- Mount the laser modules in such a way to prevent conflicting electrical connection between cases. (The green modules + case and the red modules - case)
- Don't put the modules too close to the turning mirror

I have some questions though that I would much appreciate being answered.

- In regards to the power supply, can i use 1N400x diodes to drop the voltage, or would LM317 Voltage Regulators prove more handy?
- What would you recommend for power? Wall Supply or Li-Ions connected externally via the DC Jack?
- What is the best adhesive material to use when mounting the mirror and modules? I have been thinking of using some thermal adhesive but will that stick enough?

Thanks for looking at my thread I hope you all like it and the parts come soon! I will update with photos as I go along and then eventually turn this into a thread, hopefully, about the completed laser!

It's also worthy to note that I'm going to try to build this as cheap as I can. This is my updated parts list with pricing. I'm not saying these are prices that everyone could find/ total up to. A lot of my parts being used are salvaged from other projects/ broken electronics.

Box---------------------- $3.19
Switches----------------- $3.50 (I got one for free as a spare from a kit I got a while back)
LEDs----------------------$0.00 (salvaged from light up pen)
LED Holders--------------- $0.50 (Got a bunch from an auction)
Audio Jack---------------- $1.00 (plug and jack for $2 on ebay)
Audio Plug---------------- $1.00 (^^^^)
Green Module (from pen)---$6.80 (Amazon)
PHR Turning Mirror---------$0.00
Red Diode-----------------$0.00 (friend's broken computer)
Aixiz Housing--------------$2.00 (10 for $20 on amazon)
Driver---------------------$0.00 (Got it free from Lazorlabs when they opened and had the special offer with LPC-815 selds)

Total Cost (excluding power supply) ------ $17.99

Not bad so far

Don't use fog to try to align the beam, that will be very hard to do. The beams need to have the same position and angle, at the laser, or the same position in near and far field (it's the same thing). That means that you have to align the two dots to overlap at a point very close to the laser and a point very far from the laser. That's also how I align interferometers.

Note that if you have 1 beam as reference the you have 4 degrees of freedom that need to be aligned, 2 position and 2 rotation. You can mount the lasers and dichro very precise if you don't want to have all 4 adjustments, but if your mounting is off then it's not adjustable. You can mount the modules and dircho to have the right position, then the dots are overlapping in near field. A 2 axis mirror mount on the dicro can then be used to alignt he dots in the far field.

The red laser diodes are case negative (that's a guess, check this) and the green case positive. Unless you have floating laser diode drivers or power supplies (not very likely) you'll have to mount one isolated. The easiest would be to mount one of the lasers in a heatsink that is electrically isolated from the case, the the whole heatsink assembly will be floating (watch out for shorts!).

The futher away the lasers are from the dichro the harder you need that 4 axis alignment, having the laser far away means their mounting is more critical or needs to be adjustable.

1n400 can drop a voltage, I'dd add a resistor ti have a minimum load. A LM317 is a very good regulator. It requires 2 caps but it's shortcircuit proof, has a thermal shutdown and can be easily heatsinked. It would be the neat solution if you have to drop the voltage more that the voltage drop of a LM317 (do mind the electrical isolation of it's heatsink).

the input power depends on how good the drivers can accept noisy or high input voltages. Wall adapters come in a vareity of qualities, some putting out a voltage far higher than specified under no or light load. A LM317 would regulate nearly everything, but with a decent wall adapter a good driver will be enough.

I usually mount optics with epoxy, normal glue may release gasses that can deteriorate the optics. Modules can be mounted anyway you want, just mind the electrical isolation where needed. If something goes wrong (and I've had that happen) like a diode dying you'll have to replace and realign stuff, so be sure it works when you fix things permanently to their place.

On the price: buy quality and cry only once. So make sure you have somewhat decent stuff that will probably work, being too cheap usually catches up with you in the long run. But it seems you have decent components, I just miss a mirror mount or some too to align everything.

But if I take parts I have lying around into account I can build a 2~3W green DPSS, that's cheating I hope to see this project be a succes, have fun!