Newbie... Help With 1W Laser Project.

[SKeeZ]

Hello Laser Pointer Forums,
Today i purchased parts for my 1W 445nm Blue laser. I was wondering if anyone has any pointers for building in the C6 host, soldering, etc. This is my first DIY laser build and i don't want to mess it up. I would also like to know a place to get cheap and effective laser glasses/goggles for a 1W laser. Heres a parts list for my laser.

Driver: http://dx.com/p/18v-5w-cree-circuit-b...
M140 Laser Module: https://sites.google.com/site/dtrlpf/...
C6 Flashlight Host: http://dx.com/p/c6-diy-cree-led-flash...
Heatsink: http://www.survivallaserusa.com/Black...
Radioshack CR123as http://www.radioshack.com/product...
Arctic Silver Thermal Compound http://www.newegg.com/Product...

I'd like to use some Arctic Silver thermal compound between the host, heatsink and module. I hope this will increase duty cycle. Any ideas of what the duty cycle will be?

In the future (if this goes well) i hope to do another possibly more powerful blue laser. Are there any changes you would make to the parts list (besides a bigger host and heatsink) for say a 1.5-2 watt laser? And what driver would i use for a 1.5 or 2 watt diode.

I appreciate Your answers and I promise to document this build with pictures and such as well as a video of beam shots and burning. Sorry for the amount of noobness that was most likely going on here.

 

[dubious speculation]

You can't put a price on your eyes, the surival lasers safety goggles are one of the best goggles, as for the driver i would not use the DX driver in the future.

The driver is designed for LED's and although it will work with your build the current is not well regulated. LED's are much more hardier than laser diodes and thus can take a beating. but LD's are much more sensitive to sudden bursts of current and thus the diode can degrade quicker.

In future you should buy a driver that is specifically designed for LD's, one with a soft start feature which slowly ramps up the current rather than all at once is much more desirable.

As for the duty cycle a c6 is pretty limited, i would recommend max 60 seconds on 60 seconds off.

 

[The Lightning Stalker]

Yeah, that driver is probably not going to work. It is underrated, but not worth taking the
chance unless you have a test load and know what you're doing with an oscilloscope. For
safety glasses, everyone has been recommending the ARG from AixiZ.

If you use the thermal compound be very careful not to get it on the window or any of the optics. Speaking of optics, make sure you have the right glass lens in there as acrylic lenses will not work.

 

[Pi R Squared]

That driver will work, a number of people have used it but it will under power that M140 a little but you will probably get 1W-1.25W out of it but you absolutely cannot use those batteries! They will last a few minutes at best. Get 16340 rechargeable batteries 3.7v and a charger.

I assembled a similar laser recently, take a look here:
http://laserpointerforums.com/f65/assembled-m140-c6-pic-heavy-83543.html
There are plenty of other build threads you can look at that were done in a C6 too, also there is a couple of good videos on YouTube that are helpful. Good luck.

Alan

 

[dubious speculation]

As stated above the driver will work with this build and give approximately 1+ watt with a three element glass lens.

Many people have used this driver before but as stated above the current is not regulated very well. The driver does not have a soft start feature and thus all the 1.25 amps of current is delivered to the diode instantly, which is not good for the diodes life.

DTR has also shed some light on this driver in a thread about the same DX driver.

http://laserpointerforums.com/f44/dealextreme-1-25a-driver-82612.html

 

[The Lightning Stalker]

That driver will work, a number of people have used it

It would be interesting to get it one on the scope and see exactly what's happening. The
output of switching drivers ramps up and down at the switching frequency. It can also vary in
other ways if there is PWM involved. Any harmonics/transients in there would be the things
most likely to kill a diode. I'm trying to design this out of the 5A driver I'm currently working on.

 

[SKeeZ]

Thanks for all the replies i plan to buy a different driver now that i see that it is possible that this driver will reduce the life of my diode. Even though it is an under powering driver id rather be safe than sorry.

That driver will work, a number of people have used it but it will under power that M140 a little but you will probably get 1W-1.25W out of it but you absolutely cannot use those batteries! They will last a few minutes at best. Get 16340 rechargeable batteries 3.7v and a charger.

I assembled a similar laser recently, take a look here:
http://laserpointerforums.com/f65/assembled-m140-c6-pic-heavy-83543.html
There are plenty of other build threads you can look at that were done in a C6 too, also there is a couple of good videos on YouTube that are helpful. Good luck.

Alan

if the higher capacity CR123a's wont work for long than why will 880mah 16340's last longer?

Maybe this driver will do better?: http://www.survivallaserusa.com/Survival_Laser... if so what mA should i get?

 

[The Lightning Stalker]

DTR has also shed some lighthttp://laserpointerforums.com/f44/dealextreme-1-25a-driver-82612.html

Ahh yes, he brings up the issue of overshoot. That had not even occurred to me. The problem
is that the current will actually go over the setpoint at startup due to RC time constants in
the compensation network.

if the higher capacity CR123a's wont work for long than why will 880mah 16340's last longer?

You are correct. The CR123As will last longer. At least twice as long, in fact. At 1.25A you should get at least
30min runtime. Single shot, though. Throwaway

Maybe this driver will do better?: Survival Laser USA Home... if so what mA should i get?

Yes, it will. I'm thinking to probably get the 1.8A one, but I have no experience with these diodes. 1.8A might
get too hot too fast in that little C6. Maybe someone who has can chime in?

 

[Pi R Squared]

Thanks for all the replies i plan to buy a different driver now that i see that it is possible that this driver will reduce the life of my diode. Even though it is an under powering driver id rather be safe than sorry.


if the higher capacity CR123a's wont work for long than why will 880mah 16340's last longer?

Maybe this driver will do better?: Survival Laser USA Home... if so what mA should i get?

What 880mah 16340's are you referring to? There are many different 16340's, I would recomend getting some rated at higher than 880mah. Also those CR123a's are 3v, not 3.7v, do you really want to spend $20 on something that will last a few minutes when you can get a charger and a pair of better batteries for the same price? Once you have a working laser this powerful you may want to use it frequently. At higher currents you can ignore the mah capacity anyway because they don't do as well at higher currents, the batteries drain faster. If you really want long battery life in this laser then buy the extension tube for a C6 and use 18650's.

For the driver get either the 1.5A or the 1.8A, there would be some difference in power but it shouldn't be a huge difference, it is a small host and that's lots of current for those small batteries. I am using the 1.5A in mine and the duty cycle is ok, it takes about a minute to get hot but I try not to run it that long and the batteries will be discharged enough for a power drop after only about 6 or 7 minutes. The laser is still very bright at that point but for example it can light a match instantly but after a few minutes run time on the batteries it can't light a match. The 1.8A works fine because others use them in a C6, I am just saying if you do you may have shorter duty cycle and battery life than you expected.

Alan

 

[SKeeZ]

What 880mah 16340's are you referring to? There are many different 16340's, I would recomend getting some rated at higher than 880mah. Also those CR123a's are 3v, not 3.7v, do you really want to spend $20 on something that will last a few minutes when you can get a charger and a pair of better batteries for the same price? Once you have a working laser this powerful you may want to use it frequently. At higher currents you can ignore the mah capacity anyway because they don't do as well at higher currents, the batteries drain faster. If you really want long battery life in this laser then buy the extension tube for a C6 and use 18650's.

For the driver get either the 1.5A or the 1.8A, there would be some difference in power but it shouldn't be a huge difference, it is a small host and that's lots of current for those small batteries. I am using the 1.5A in mine and the duty cycle is ok, it takes about a minute to get hot but I try not to run it that long and the batteries will be discharged enough for a power drop after only about 6 or 7 minutes. The laser is still very bright at that point but for example it can light a match instantly but after a few minutes run time on the batteries it can't light a match. The 1.8A works fine because others use them in a C6, I am just saying if you do you may have shorter duty cycle and battery life than you expected.

Alan

You do have a point. the 18650s are a much better option. The CR123a's capacity is similar to the 18650's and in the long run buying some of the 18650s and an extension tube is the better bet. Thanks. I also have an idea for a driver now too.

 

[The Lightning Stalker]

That should do you quite nicely. I may be looking into something like this myself eventually.

Don't forget about the safety glasses!

 

[hakzaw1]

there is lots of debate when It comes to duty/rest cycle.

I tend to run all mine with a long lifetime in mind- honestly I cant really remember the need for super long run times.

This altough kinda crude may be a good guide-
1) the ambient temp plays a role- in winter we can run longer in summer not.
2) any powerfull laser with a small(ish) heatsink must be babied.
3) when you feel an increased warmth around the head of the laser this is telling you it is quite warm inside.
4) when quite warm on the outside it must be kinda hot inside-
5) when hot on the outside (depending somewhat of which diode) you may have already shortend the life span of the laser as it would have been VERY hot inside.

of course this will vary

also avoid rapid off and on- lasers do not like that very much. Only Lab Lasers are made in a way that lots of quick on and off is of no concern- it is done in a different way (ttl) some labbes have active cooling like a fan and /or TEC- they generally have much larger heatsinks too. Pointers and most handhelds have passive cooling.

good luck with your build- watch out for ESD and overheating with your soldering iron.
Many first time builds end badly- and those are AFAIK the two main causes.

Pressing the die into its seat is best done with a tool made for that purpose.

Go easy with the thermal paste a thin coat is enough and too much may just end up on the face or your diode--not good!

use good flexible wire--- silicone wire is the best. use shrink on all your soldering joints.
Check out all the building tutorials especially those by DTR- hos pics are a huge help.

Take your time- rushing often makes some forget about the ESD.

Be sure also to use the correct pin-out for that diode.
Not all are the same--

hak

 

[SKeeZ]

I decided to share an update with the final parts list for this laser:
C6 Host
M140 Diode
Standard Heatsink for C6
Momentary Switch (I've yet to modify to make this work)
16340's
Survival laser Fixed Current 1.8A driver
-
My methodology on the momentary switch is for both safety and Duty Cycle
A momentary switch will give me less urge to leave the laser on for long periods of
time and i was too lazy to make 20 bucks to buy the extension tube... maybe in the
future. I think ill get some nice Eagle Pair Glasses to protect my "seeing balls"
because they are priceless. I plan to get the one that protect form 190-540 AND
800-2000nm because you can never spend to much on safety.