Portable condensation proof TEC housing

[bloompyle]

So, say you had a 150mW C-mount diode that operates at 5*C. Say you wanted to take this diode and put it in a portable host, like the MS-SSW. Now say you knew how to hook it up to a TEC, but you wanted to avoid the evil condensation destroying all of your wonderful electronics. What would you do?:thinking:

 

[Photonz]

I'm stumped on this one but i'll give you a bump to bring in more attention

 

[BShanahan14rulz]

I've got some dessicant packs you can use, but you'll have to keep replacing them unless you seal up the cold side, right?

 

[bloompyle]

Would those work? Seems too simple, though ingenious at the same time.. It would be sealed up in the pill of the host, all one object. Plus it'll be fixed focus so I will epoxy the lens in place. I can add epoxy or silicone anywhere I need to So in theory it would be sealed VERY well.

 

[Lazerbeak]

I've been wondering about this too Bloom. I wonder if a non-electric moisture absorber like using white, calcium chloride crystals could be used. Moisture Absorber - Humidity Absorber | DampRid

I see them used in shipping a lot. A small packet inside the heat sink or maybe it would be possible to vacuum seal the chamber :thinking:

Good question.

Edit...

Doh! Bshanahan beat me too it

~ LB

 

[grainde]

If you make an air tight seal, with some desiccant inside as the others have mentioned, no air can flow in or out and so no moisture will get in. You can also use silica gel packs, they often come bundled with electronics; put them in the oven first around 100 °C - max 150 °C. :beer:

 

[bloompyle]

Much easier than I thought. All right! Now to find a good TEC, and hopefully we can get some planning.

 

[ZRaffleticket]

I'm looking forward to seeing the finished product.... PM coming shortly

 

[bloompyle]

Working on getting a custom c-mount host from Sinner.

Problem, how am I supposed to do anything about the air between the diode and lens? I can't block the output with a gel packet.

 

[djQUAN]

I don't think you should worry about it for the reasons IMO:
-the diode will heat up above the case temp so no condensation will form on the diode die itself.
-the lens will probably heat up due to the high power output (this is a high power laser, right?)
-the case surrounding the diode and lens will be relatively cooler so if condensation does form, it will be some place you won't have to worry.
-the air space will be very small so there won't be much humidity in the air unless you live by the sea side or rainforest where it is very humid.

Well, that's what I think would happen but I may be wrong

 

[Meatball]

Buy a vacuum pump. It doesn't have to be a monster one. It would not take much to empty such a small cavity of water vapor. The focused can remain fixed, and you don't have to worry about replacing moisture baggies over time. There are many epoxies that could make such a nice seal.

A note on using TECs in a portable host...

well.

They take tons of current in order to function at all -

When they do function they are very inefficient -

They must be actively cooled to keep the cold side "cold", you must use a fan -

They can actually heat your target if your active cooling isn't good enough.

If by "150mw" diode, do you mean one of the 638s? Are you going for cryo cool for the lambda shift? Or just for heatsinking?

After considering these things, do you have a heatsink large enough? Will your cells be able to supply enough current? For how long?

Let me know if you've got ideas - for now these are the only things I can remember to consider.

 

[bloompyle]

It's a 622nm diode. I guess I might have to put the breaks on this plan for a while.. I'm going to own it, portable hopefully, probably labby. We'll see..

It's going to be in a large 2 cell 26650 MS-SSW. LOTS of metal here, lots of mAh, the TEC should (in theory) survive. Basically just like Angelos did with his 2.1W 650. Just with some desiccant

PS, talked to Amber today. Got some info in the area, lasers came up, but just because she asked what I wanted to do. Didn't explain my story or anything. She said she didn't have access to setting up tours and labs because she deals with people fresh out of high school, etc, etc. So she said said she'll give me some contacts and I can get started there. Didn't mention the first voicemail, assuming it doesn't exist