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ThermoElectric Coolers (TECs)

Gazoo

Gazoo

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Ok...now I understand. I have the same problem as you with no access to machinery, so I make do with what I have. I don't remember if I told you, or if you saw my post, but today I ordered another Meredith module and the mounting block. I already have one Meredith module and I wish I would have ordered the mounting blocks when I ordered it. Link follows:

http://www.mi-lasers.com/cgi-bin/shopper.cgi?search=action&keywords=diode_optics

I figure it is much easier to work with something square... ;D I will be using this for my next TEC project.
 





Hemlock_Mike

Hemlock_Mike

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Gazoo --

Good post --- YES -- I'm pushing GB and open can diodes to the MAX.  I'm posting this info for advanced experimentors only.  I'm reporting limited output increases at HIGH current -- for short periods and TEC cooled.

DON'T TRY THIS AT HOME   ;D   Please enjoy your LD's at recommended current.  You will go to bed happy !!

Mike
 
E

ericab

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here the heatsink ive been working on today...

the peltier (coming in the mail) will obviously sit on top of the copper plate.
the brackets on the 4 sides ( they are actually corner mounts which just happened to fit almost perfectly around the assembly) will keep the peltier from falling off on any of the sides. im also going to feed the peltiers + and - through the holes on the brackets.... now the bolts/washers/nuts you see on the 4 corners; as soon as i buy a plastic pedestal type thing from tap plastics are going to mount into 4 holes. obviously its going to be elevated enough to allow the fan which is the black piece on the bottom to get proper circulation. the piece from tap plastics is going to have a circular hole which will allow the heatsink assembly to drop down into the pedestal, where the metal tabs will stick out just enough to stop it from falling all the way through....i like how its turned out so far... thank god for dremels. what do yall think?

links:

http://img337.imageshack.us/my.php?image=cimg1205uy5.jpg

http://img206.imageshack.us/my.php?image=cimg1204hs6.jpg

-eric
 
Hemlock_Mike

Hemlock_Mike

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JES --

That 400 mA LD current I posted about is under very controlled conditions. I was reading 4 meters and slowly approached this level with TEC cooling.

There is no real benefit to you by pushing the GB diode beyond 250 mA. I have a bunch of them to push and throw away.

Mike
 
T

Things

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you guys have some great plans for these little TEC's!! i'm ordering a few tonight to have a play with, but they aren't the little ones you have there(how big are they?), the ones i'm getting are about 40mm by 40mm, and draw about 15volts @ 4amps. they freeze water instantly!!!! they are the funnest little things to play with!
 
E

ericab

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the one im fitting on my heatsink design above is 50mm x 50mm x 3.4mm.... overkill; but hey...

all in good fun :cool:
 
J

JES

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Gazoo said:
Ok...now I understand. I have the same problem as you with no access to machinery, so I make do with what I have. I don't remember if I told you, or if you saw my post, but today I ordered another Meredith module and the mounting block. I already have one Meredith module and I wish I would have ordered the mounting blocks when I ordered it. Link follows:

I figure it is much easier to work with something square... ;D I will be using this for my next TEC project.
Click to expand...

That looks sweet. I had imagined machining something similar that would allow swapping out of Aixiz modules when new LDs came on line. You could do that with the Meredith modules. You could mount multiple TECs on it if you need to.

How much is the mount and how much are the collimating lenses?
 
J

JES

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ericab said:
here the heatsink ive been working on today...

the peltier (coming in the mail) will obviously sit on top of the copper plate.
the brackets on the 4 sides ( they are actually corner mounts which just happened to fit almost perfectly around the assembly)  will keep the peltier from falling off on any of the sides. im also going to feed the peltiers + and - through the holes on the brackets.... now the bolts/washers/nuts you see on the 4 corners; as soon as i buy a plastic pedestal type thing from tap plastics are going to mount into 4 holes. obviously its going to be elevated enough to allow the fan which is the black piece on the bottom to get proper circulation. the piece from tap plastics is going to have a circular hole which will allow the heatsink assembly to drop down into the pedestal, where the metal tabs will stick out just enough to stop it from falling all the way through....i like how its turned out so far... thank god for dremels. what do yall think?

links:

-eric
Click to expand...

Good work. It is going to be quite cold and rather pretty.
 
J

JES

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Hemlock Mike said:
Gazoo --

DON'T TRY THIS AT HOME  

Mike
Click to expand...

Mike your caps lock got stuck there for a second. I can't quite make out what you said! Perhaps I am just too distracted by thoughts of pushing LDs.

Jim
 
Gazoo

Gazoo

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JES said:
How much is the mount and how much are the collimating lenses?
Click to expand...

Jes,
For the specs and prices, click on the pictures. There are two modules that fit in the block. One comes with a glass lens and the other an acrylic. The first one I ordered with the glass lens. It makes a nice beam since it has a bigger diameter, but because of this it doesn't burn as well as the Aixiz lens. I put an Aixiz lens in my Meredith module and that solved the problem.

This time I ordered the Meredith module with the acrylic lens. According to the specs, the beam diameter is a good bit tighter than the one that comes with the glass lens. So we will see when I get the modules.
 
J

JES

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Hemlock Mike said:
JES --

That 400 mA LD current I posted about is under very controlled conditions. I was reading 4 meters and slowly approached this level with TEC cooling.  

There is no real benefit to you by pushing the GB diode beyond 250 mA.  I have a bunch of them to push and throw away.

Mike
Click to expand...

That is how I envisioned doing it; slowly and taking temp readings on the LD. If you push the diode hard in a burst, it will get hot faster than the TEC can compensate. I figure that most usage will be a burst though so that leads to a problem.

Also, our cooling is going to be custom for each of us since the builds are diverging. There is no one answer as to how hard each setup can be pushed safely.

What is the upper temp in this LDs safe range? That is a key number.

How fast your Peltior can move heat off of the LD is another key number. If it takes a few moments for the effects of the Peltior to be felt on the LD, then there needs to be cooling prior to use.

Did you log your output readings at different levels of current? Is 250mA a sweet spot or just a safe number?

I wish I had your resources. I have two LDs on the way so it is probably best that I think through things before I get my hands on them.
 
J

JES

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Gazoo said:
This time I ordered the Meredith module with the acrylic lens. According to the specs, the beam diameter is a good bit tighter than the one that comes with the glass lens. So we will see when I get the modules.
Click to expand...

Ok.  Let us know how that works.  I may follow you down this path.  It would somewhat standardize cooling setups and let us pool our observations a bit better.  The mounting block is a no-brainer at that price.  I do wish their lens assembly was less expensive.
 
J

JES

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Gazoo said:
As far as cooling, I let my module get cool then slowly turn up the current. Following is a link to the datasheet:
Click to expand...

I do wish that Temperature Dependency graph were larger.  They don't really give the specs we are looking for either but since they have a graph line for 75C (167F) we can guess this as an upper limit.

It also looks like the difference in output from roughly 275mA to 400mA is dependant on heat.  If the diode is kept at 20C vs 75C the same amount of output can be generated by a diode running ~275mA as one being run at ~400mA.

In short, as we know, cold rules.  Makes me think of that square module you found and another Peltior.

-Jim
 
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