DIY 1W 808nm lab build project, Help needed

Im planning on building a 1w 808nm lab style laser for a college technology award scheme. (i have to produce a logg on building and a detailed write up after im finished.) im going to take pictures and videos of my progress which i could post here aswell as in my project logg. The award scheme requires you to investigate or build something to do with technology and i thought what better then to build a powerfull laser.
In the project i could talk about the affect of different currents, voltages and lenses on the output power and heat production of the diode. i could mention the wavelenth of the infrared aswell as the dangers and uses of lasers. there are countless things i could write about for this project which would help me learn aswell.

So now to the build;

-To my knowledge there are a few different types of 808nm diodes, cmounts and cans. but i have only seen cans go up to 1w, which seems to be perfect for my build. these are 9mm diodes or TO-5 or something.
Heres where i am abit confused; there are cmounts which are also 1w, are these better then the 9mm 1w?. id rather not go with a cmount as ive read that theye are harder to fit and allign with lens, as well as harder to focus because there multimode.
I would need help selecting the right diode and best place to purchase it, (forum, ebay etc)

- for the module i was thinking of going with the merideth 9mm glass module, if i was not going for a cmount. however i do not kno of any modules already made for cmounts.
Are there any other places i could get a 9mm module like merediths for cheaper?. i think my college will pay for most of this so meredith shouldnt be a problem.
Meredith module
Meredith Instruments

- for the heatsinks, i decided to try building myself or i could buy one if its available.
would this work as the heatsink for a 9mm module?
Lab style heatsink for 12mm laser modules - $21.99 : Modwerx Shop

-After searching around ive read that a 808nm infrared diode needs around 2v and 1 to 1.5A. ive read that the flexdrive can handle this, but since im building a lab laser i wouldnt go for something that small.
i could build a lm317 driver, which was what i was considering until i came across this,
K18231A Power Supply : Miscellaneous Kits : Maplin
This seems to be a driver that has 1A output (okay for 1w 808nm) and can provide voltage between 1-35v. seems very reasonable if i am correct in thinking it can be used to power a diode, im not very sure. which is why im asking.

Finally, and most impotantly, where can i get good safety glasses for infrared?. i need around 3 as i have 2 more people working on this project with me and would also need to show it off.

Wow that was alot of writing, forgive me for boring you, but i would really appreciate any help that can be given!,

Thanks!

I think you would have a better "wow factor" with a medium power green.

A nice visible beam would command a bit more attention than a invisible laser.

BTW your not boring.

lol thnx,
How would i go about building a green one?,
Would i just buy the crystals and place them infront of the ir diode?. i have seen some people just hold them infront for demonstration which i could do easily. but mounting it in could be difficult. could i have a sort of add on assembly that converts it to green and infrared/ vise versa?

To make a green DPSS you're going to have to do a bit of reading. It's a lot more then just pointing and shining an IR diode through a crystal and getting green. You should be familiar with cavities, proper alignment, and be able to make very stirdy adjustments. Another thing to consider is that for pumping large amounts of power from the IR will still only get you very little power from green. Laser_Ben does an awesome job going over it here

http://laserpointerforums.com/f45/so-you-wanna-build-green-laser-42093.html

I am in no way trying to deter you from this project, in fact I wish to some day build my own green DPSS as well. I am merely trying to inform you of the process involved in an attempt to save you from wasting time/money :angel:

Thanks for the info, i will need to do some more research in to building a green dpss.

but in the meantime i still need advice as to what parts i should get, and if the info i have posted in my first post is correct.

i am particularly interested to know if that maplin driver i found will work in powering a diode,

Well after your confident enough in your ability you can look at this thread and it'll give you at least an idea on what is needed as for parts and assembly

http://laserpointerforums.com/f45/do-yourself-complete-green-dpss-o-like-crystals-42495.html

I found this focusing module which is considerably cheaper then the meredith one.
9mm Laser Diode House/Case/With Lens/ Laser Industrial - eBay (item 260545760552 end time Mar-01-10 09:16:35 PST)
Just want to make sure if this will work with a 9mm 808nm diode. Is there a cheaper one i could find or is this one not good?

I have also found many 1w 808nm diodes on ebay but dont know which to buy is there a reputable seller that people on this forum normally go to?

I am still lost on whether the maplin driver;
K18231A Power Supply : Miscellaneous Kits : Maplin
Would work for the 1w diode.

My advice would be to just go with what is tried and tested, you are more than welcome to go out and try new things, but often they won't work.. That's how this community works, we go out try new things and report back when it doesn't work... But since you seem to be on a budget I suggest sticking with what is guaranteed.

That module would work, but for the sake of a few dollars you would be off going with the Meredith, better quality and more precise fit.

For a driver do a search for DDL, depending on what current you need to go up-to, you can adjust the driver accordingly with slightly different components and advice from people here. It cost's a few dollars to build and you can get all the parts from maplins, I know because I've built a few with parts from there

Another option would be too look at flex drive or rcsktr, but they are expensive and since space isn't an issue and current limit is, go with the DDL, plus you can right up exactly how it works because you built it !

High power IR diodes, well I would probably say your best bet is to check ebay, I personally don't know of any laser stores recommended here that sell them, because not many people what invisible high powered IR lasers

One thing I would recommend though is talking to Billg15, he has SEVERAL great high powered IR lasers, and he is definitly the guy to talk too if you are serious about putting this together

I'm not sure if you are still interested in putting together a green laser, but I personally would go with the IR, it's easier, cheaper and A LOT less hassle... Obviously not as impressive, but you'll save a lot of time and money.

Also remember BUY IR SAFETY GOGGLES, these lasers will melt plastic and set wood on fire... They will also do the same to your eyes.

Thanks for the help.
After reading about the DDl driver i used circuit wizard to try making a simulation of what i would require;
Here is the diagram, i coudnt find an LM317 component in the library so i used a 3 pin terminal.

This is where i am confused a little. for a simple red or bluray diode i know how to configure the circuit to give between 0-500 ma.
The maximum current output of the LM317 is 1.5A. What if the 808nm diode i buy requires that much exactly?. do i not put any fixed resistor at all?.
Since the Current range is high (0-1500ma) what variable resistor do i use?

I was looking at some current inputs on some 808nm diodes and it was between 1-1.5A.
so i came up with some values for the fixed resistor

1A= 1.25/1= 1ohms

1.2A= (1.25/1200)*1000= 1.04 ohms

1.3A= (1.25/1300)*1000= 0.96 ohms

I dont even know if the way i calculated it is correct. I am not sure if such varied amount of resistors are even available.
I think my solution would be to have NO fixed resistor and then use the potentiometer to lower the current from 1.5A to the desired (1.3,1.2,1)

Another thing, what is threshold current?. the diodes i have been looking at have threshold currents from 250ma or so.

Thanks alot for all the help so far

Please correct me if I'm wrong but isn't that the constant voltage configuration for an LM 317 regulator? I haven't built one in a long time but I recall the LD current needs to pass through the resistors. And that first diode is backwards shorting power to the LD.

HMike

Thanks, i changed the position of the diode.
I dont know what you mean about the diagram being setup as the constant votage configuration, but i tried to follow the diagrams on other sites carefully.

i visited my local maplin today, and brought several things;
-10 LM317's (for future use)
- A resistor Pack ( Lots of values)
- A diode pack (Lots of values)
- Capacitor Pack
- Strip Board
- Battery Holders
- Switch
- Alluminium Enclosure
- Power inlet port (For power adapter)
- Wire
- Potentiometer
- lm317 heatsinks

I started by testing the LM317 and tried different values of resistors after calculating What output they would give me, it was exactly the same which made me very happy as it meant i calculated it porperly.

I then tried connecting the lm317 without any resistor to find its maximum current, this was around 1.8A. So this means that it is necessary for me to use a resistor.

I then tried getting 1-1.5 Amps of current, but couldnt find a suitable resistor for it. i tried 5 5ohm resistors in parallel and that gave around 1.3 amps which was the maxixmum value i have seen for a 1w 808nm diode.

These 5 resistors in parralel began to get quite warm, so i am doubting that this was the proper way to hook them up, maybe i need a higher wattage resistor?.

I have looked through some of the other threads for this same type of build and no one has stated what value components have been used.
I would appreciate it If anyone could help me out on what values and type of components i could use for the;
-Resistor
-Capacitor
-Variable resistor
-Diode
To get between 1-1.5 A.

Also i have ordered the IR diode,
808nm 1000mw 1W burning IR laser diode. USA 3 day ship - eBay (item 270525384950 end time Feb-12-10 17:41:02 PST)

Which requires 1-1.3A

I have also ordered a meredith module, but looking for a good heatsink block for it to mount in the alluminium enclosure i have.

Thanks again

EDIT;
I just made my first driver as a test. this was for a PHR which i will buy in the future sometime. i didnt include a potentiometer but the current output is 96ma so its ok. i just wanted to practice using the striboard as i hadnt ever used one before. i used 3 4.3ohm resistors in series to reach 96ma.

When your five resistors in parallel got warm, they were telling you to use higher wattage units, or a supply voltage as low as possible. (Need Vf of LD plus about 3V for LM317 overhead.) A linear regulator simply turns excess voltage into heat. Too low of a supply voltage, and the device will drop out of regulation. You can drop excess supply voltage with a series diode or two, rated to pass the current that the circuit will draw. If the LM317 gets too warm, you can substitute an LM350 (3A) or an LM338 (5-7A). The calculation for the resistor remains the same as the reference voltages are the same (1.25V) for all 3 chips. Nice work on the strip board. You can get into needing fractional ohm resistors for higher current loads, these can be made from heating element wire. Measure the resistance of a foot of the wire, figure out how long you need to get your desired resistance. An alternative for driving a 1W IR LD is a DX flashlight driver disk, you could try a 1050mA one. An advantage of this one is that it is a negative side driver, so it is suited for a positive ground host and diode. (IR LD is positive ground of course) You can make a negative side driver with the LM337 adjustable negative regulator.

Thanks for the help
I wont be able to post any updates anytime soon as i am off on a cambridge trip, so will carry on after im back.
Thanks

hey ive been thinking of making a high power IR laser for a while now. @slifer make sure you post if the ebay diode is legitimate and really 1 watt! i would probably buy one of them. also does anybody know where to get good glasses for 808nm? i was thinking dragonlasers possibly...
thanks

any updates with the build?

Hey guys, sorry i havnt been posting for a while. been very busy with exams.

But i did manage to start the build with loads of ups and downs lol.

-I made 2 drivers, one for a PHR and one for an LPC-815. i didnt use a pot for any as by using abit of physics (resistors in parralel and series), i came up with exact values .
436ma for the LPC and 96ma for the PHR. (Both using only 4.3ohm resistors).

-I ordered Aixiz modules and the diodes from modwerx.

Both of these lasers are working perfectly, all i need now is a nice enclosure and heatsink for them.

Now for the main build!
After alot of testing between different resistor values and resistance wire i finally made a driver that outputs 1.5A without the resistors getting too hot. i used 7watt resistors. I also have several heatsinks for the LM317 so they are also kept cool.

I also recieved my 9mm module and 808nm diodes. sadly i blew my first one while testing, as the ADJ and Output pin on the regulator shorted outputing very high Amperage, destroying the diode.

The second one met with a similar fate as i snapped one of the pins while press fitting it. since the diode is case positive i thought i might be saved but unlucky me it was the negaive.

I did manage to repair this diode by soldering a resistor lead to the tiny terminal andthen secured it with epoxy. it worked but then because of all the heat i punished it with trying to solder, the diode blew after using it for a short time.

Currently i am waiting for my third diode to arrive so i can finally put it together.... hopefully.

While the diode were running it was working like crazy. burning almost anything i put in its way. focusing wasnt even too bad as i could burn even 30-40 cm away. hopefully my new diode will be up to spec like my previous ones.

This laser is being made by me mostly for a fun project, but for our school investigation i have decided to use the laser for power beaming. i need to find some photovoltaic solar cells and direct the laser toward the panel and measure the power being transfered. i could do this at several distances getting further away and then evaluate the power loss and efficieancy. NASA did a simialar experiment and were able to fly a model aiplane for limitless time using an ir laser from the ground. i obvioulsy will just be using solar cells at fixed positions as it would be a pain directing light.

I am almost 100% sure that visisble spectrum lasers will work on normall solar cells, but then 808nm isnt in the visible spectrum so i need to investigate what sort of panel i would need to conduct the test.

At hugo999999;
I cant be completely sure whether the diodes i recieved from ebay are infact 1w of output, they did burn alot better then my red (250-300mw). i am actually overdriving them at 1.5A when recommended is 1.3A. Also these diodes i bought do not have FAC (Fast axis correction) so because the diode is multimode (more then one laser die in the case), it is alot more difficult to actually focus the power that is outputed, so there maybe loss.
Someone may need to correct me on this as i could be wrong.

I will keep u guys updated and there are lots of pictures to come