New Host Mini BR!!!

[IgorT]

Nice!

I'm making one in this exact same host, but with a PS3 diode for quadcam. I also wanted to try it with a PHR, but there is no room for a heatsink...

If the host was a little tighter, it would help dissipate the heat a little. Did you manage to put anything in between?

 

[Maven]

IgorT, you could probably get who ever is making you those heat sinks to just machine you out a piece of aluminum to your specs on a lathe pretty cheap ... if not maybe i could help (i just hate the post office)

i have access to lathe and milling machine at work and can make all sorts of cool stuff ... i plan on buying some round aluminum stock and just making my own host for my dx true 30 ... i might buy one of those driver kits off someone so i don't have to go pick up the pieces... but then again i saw an awesome touch activated laser the other day on a link from someone's post i really want to do that ....

maybe i could barter some aluminum for a blue ray diode ... hint hint

just thought about it some more ... maybe you were saying that there isn't any physical room in there for a heat sink not that you just didn't have one the right size... either way i am thinking about making a blue ray myself and i gotta find somewhere to get the diode

 

[IgorT]

Well, i like small lasers very much, and i ordered these tiny hosts a while ago, just to test them out.

The head has almost the perfect ID for an AixiZ module. I mean, it's so close, it's almost frustrating..  :
If there was contact, the body would help dissipate some heat. It would still require a duty cycle, as the shell is thin, but at least you would then feel the heat outside, and know when to shut it down.

The module is slightly loose in the head, but it might be possible to wrap something around it, so there would be some contact.... If you push it to one side, there is like 0.7 - 1mm room on the other. So yeah, it's about physical room. The "heatsink" would have to be around 0.3mm thick.. Maybe less, not sure. The best thing may be to make the module thicker, by wrapping some thin metal around it or something.


That's why i was asking if he managed to stick something in between. I would still like to make myself a blu ray or two using this host. I have some diodes left, that were too weak for use in my lasers, so i could put them in here, and power at a more normal current, where heatsinking is not that crytical... But i still wouldn't want them to overheat..



I make the other heatsinks myself. At 160mA (doing 166mW after plastics -  an above average diode), i left a laser on for an hour. 33°C after 30 minutes and 36°C after one hour. But since we are pushing these diodes way above their ratings, maybe even above their pulsed ratings, you never really know what will happen. It can work long enough for you to believe it'll make it, and then just crap out one day, even if the heatsinking is perfect.

We don't know that much about these diodes yet.. In fact, i could even imagine a scenario, where heat would make a diode live longer!

 

[clwatkins10]

Wow, that is a very nice br you got there

 

[Kai]

Alrite, a couple things I wanna touch on:
Heatsink: theres not just one way to get good heat transfer because the quality control on these LED's aren't very good; meaning their ID varies from one another. The way I overcame it was to JB weld a winding of very thin copper wires around the Aixiz module which gave it a tighter fit in the barrel. Then to further help the heat transfer, I used artic silver around the winding.
Driver: I used a Flexdrive 2 range set to 175mA.
Duty cycle: I average around 2-3 minute runs but have had a couple of 7-8 minute runs as well and the thing still burns like a champ!
Glad everyone likes it!

 

[Maven]

ohh i just had a cool idea ... you could get some sheets of shim stock and get the perfect thickness and just cut off the right size piece to wrap around your module and get it to fit perfectly into the host ... atleast it sounds like a good plan to me ...

 

[IgorT]

175mA?   That must be like 150-160mW!


Let's hope it lasts... The one i had at 180mA died after a week, and the one at 170mA after two weeks, in both cases an hour of use per day on average, but sometimes up to two. Both with a heatsink, that prevented them from ever heating up above body temp.

At the moment i've been running one at 160mA for almost a week, and i still don't know if it'll make it. I noticed a small power drop, which always happens just before they die, but i'm still hoping it's just dust on the lens..  

 

[Kai]

I dont know how much power its putting out but its been going strong for a lil more than 3 weeks now. ;D

 

[IgorT]

How many minutes use per day?


You should really have the power measured by someone man! Because, depending on the diode efficiency, this could be important info.
I noticed, that higher efficiency diodes die sooner and at a lower current, simply because of more optical power. Lower efficiency diodes can take more current, as long as the optical power is lower.

That's why i'm trying to gather as much info as possible - to compare the results.. It would be great, if you knew your power.

 

[Kai]

I'd say on average about 25 minutes per day

 

[Kai]

oh hey Igort, can u do some current/ power tests for me? im trying to write a formula to figure out output power using current and voltage inputs for the PHR's. It wont be dangerous for the diode or anything; I ask you cuz I know you have a power meter and are familiar with the works. Let me know if you're willing to help.

 

[IgorT]

Well, at 25min per day, my dead diodes might also still live.. But i leave them on for at least an hour a day. Sometimes up to two, just to see what happens.

About the power vs. current.. I already made a list of powers for 29 diodes, most of them at two currents, and some with more than that. Did you look at my PHR batch testing thread? Look here: http://www.laserpointerforums.com/forums/YaBB.pl?num=1214268330/7#7


Otherwise, DrLava made a graph of PHR diode power vs. current. That graph confused me for a while, cos my first few diodes measured considerably lower than that. I thought his graph was without a lens!

But it turned out, the diodes just vary A LOT! You can't really tell the power from current. There is a certain average....

Also, the difference between them is not only in the plot being moved up (if it's more) or down (if it's less powerful)...
Two diodes can have a different power at one current, and the same power at another current, meaning the behavior is not linear.

So a graph for one diode will only match that diode, and not be useful for much else.


Most move around a certain average power, but some are WAY higher, and others WAY lower.
I had one, that only did 130mW at 190mA! And another, that did 195mW at 180mA.


That is why i said your power must be between 150-160mW - that is if it is a normal diode. If it's a 1 in 30 freak, then it could be almost 200mW! If it's a weak low efficiency diode, it could be 120mW in the worst case. So it's really hard to tell, and a formula would not help much.

 

[Kai]

ehhh... i thot i'd give it a shot, but i figured like u said; there's too many variations. but yea, so u mean to say that u kept ur laser on for 1 hour continuously?! nice. haha yea i dont think mine will handle that kind of run time.

 

[IgorT]

No, not 1 hour without a break every day..


The 1 hour continuously is just when i test how it handles the temperature, at different ambient temps, and different current settings. I leave it on for 60 minutes, and measure the temp with an IR thermometer every five minutes..

But on most days it's just 20-30 mintes at night + a minute or two when i pick it up, every so often, which then amounts to about an hour total use per day (on average), when i'm not doing tests. But this by itself is also a test.


I torture them on purpose - if one fails, i want it to fail in my hands, so i can figure out if there is something wrong, and how to improove it. By pushing them harder, any flaws would show sooner.

Other than that, i also want to find the max power, the diodes can handle. This way, i hope to eventually figure out, how far they can be pushed relativelly safelly.

 

[Kai]

>>>175mA<<< hahaha :

 

[IgorT]

I said max safe power, not current. A less efficient diode will be able to survive more current, as it will produce less power at that current. A more efficient diode can easily die at a lower current, if it suffers COD, from all the optical power it put's out. The more the diodes vary in eficiency, the more the max safe current will vary.

That's why i think it would be interesting, if you had it measured.