Blu-ray with TEC!

[lasersbee]

Labels is good

 

[artix]

Put a glass lens on the red one then take beamshots!

 

[jayrob]

Good idea!

I should have used a tripod for the camera though...
Jay

 

[artix]

Good idea!

I should have used a tripod for the camera though...
Jay

I love beam shots! (well, everyone here does :)

 

[ArRaY]

Wow! That violet color is the best I have seen on a picture yet!
Your camera picks up the blu-ray color very well!

ArRaY

 

[thesk8nmidget]

holy fog! but the beam almost looks pink from all that red!!

good work im finishing up tec build right now. just need to wait for a cdouple diodes!

 

[suiraM]

Regarding the peltiérs, for those who asked, they are current driven devices, not voltage driven. Some peltiérs do not handle higher voltages too well at all. Others are quite happy with it. I assume this depends on the internal wiring and internal resistance (think of it as a huge lot of diodes that can be wired in parallel, series, or series-parallel).

Making sure they don't cool the diode too hard is probably a good idea, as the thermal shock is just going to get a whole lot worse if the diode suddenly heats up, then suddenly cools down to below its operating range, before returning to room temp with lots of ups and downs when you power it down. If you've got an IR thermometer, you can get a good temp reading and try to rig it for about 0 Celsius (32 Fahrenheit).

Proper temperature control is a bit of a fine art, but this kind of active cooling can still be a good tool for hobbyists. I prefer to keep careful track of the temp and current curves if I can, but that requires a microcontroller (or a lot of analogue electronics to do the same thing), and isn't really needed if you're not trying to maximize reliable power or doing holography and the like.

-M-

 

[Spyderz20x6]

Good idea!

I should have used a tripod for the camera though...
Jay

Are you supposed to use a high ISO or low ISO? I cannot seem to figure that out...

 

[jayrob]

Wow! That violet color is the best I have seen on a picture yet!
Your camera picks up the blu-ray color very well!

ArRaY

The first two pictures are very much like your standing there... The last one is over exposed and out of focus.

holy fog! but the beam almost looks pink from all that red!!

good work im finishing up tec build right now. just need to wait for a cdouple diodes!

Can't wait to see what you cook up sk8! Show some pictures...

Regarding the peltiérs, for those who asked, they are current driven devices, not voltage driven. Some peltiérs do not handle higher voltages too well at all. Others are quite happy with it. I assume this depends on the internal wiring and internal resistance (think of it as a huge lot of diodes that can be wired in parallel, series, or series-parallel).

Making sure they don't cool the diode too hard is probably a good idea, as the thermal shock is just going to get a whole lot worse if the diode suddenly heats up, then suddenly cools down to below its operating range, before returning to room temp with lots of ups and downs when you power it down. If you've got an IR thermometer, you can get a good temp reading and try to rig it for about 0 Celsius (32 Fahrenheit).

Proper temperature control is a bit of a fine art, but this kind of active cooling can still be a good tool for hobbyists. I prefer to keep careful track of the temp and current curves if I can, but that requires a microcontroller (or a lot of analogue electronics to do the same thing), and isn't really needed if you're not trying to maximize reliable power or doing holography and the like.

-M-

Hey thanks for your input here! It's good to learn a bit more about the peltiers...

At 546mA's to the peltier, it dropped about 2 1/2 degrees from ambient room temperature after a 5 minute test run at 186mA's to the 803T diode. Seems to be a good place for that power don't you think? Any advice is appreciated...
Jay

 

[thesk8nmidget]

yeah i should really stop slacking and snap some pictures!

i'll do that tonight!

 

[suiraM]

Hey thanks for your input here! It's good to learn a bit more about the peltiers...

Cordially welcome. It's always good to know more about anything, really.

At 546mA's to the peltier, it dropped about 2 1/2 degrees from ambient room temperature after a 5 minute test run at 186mA's to the 803T diode. Seems to be a good place for that power don't you think? Any advice is appreciated...

As always, it depends on the application. As a rule of thumb, inside the recommended temperature range, the lifetime of a diode will double for every 10 degree Celsius drop in its operating temperature. I would hesitate to go much lower than 10 degrees C, however, due to concerns about condensation of moisture and so forth. If that is not a concern (it may not be, depending on how tight the module is), then I would not go below 0 degrees C.

However, bear in mind that thermal shock is what tends to kill the diodes in the end; that's part of the reason they tend to die at power-up, as I understand it. If you have a circuit to slowly power up the diode (say, 3-5 seconds for a portable one, although up to 15 minutes is beneficial if you don't actually need the laser to come on quickly), and then use a simple thermistor or the like on the hot side of the peltiér to set the drive current based on the temperature, you should be able to keep the thermal shock to a bare minimum, even when the final power level is very high.

I'm working on a rig to characterize the 803's in more detail, and will hopefully be able to give more useful input when that's done, but I have a lot on my plate right now.

Health,
- M -

 

[originalbigT]

that is a sweet build! Nice heli! I have a walkiera with a brushless upgrade. But it now has servo glitch

 

[jayrob]

Good stuff suiraM... thanks for this technical information!




originalbigT, thanks!

Man, having a glitch is a bummer. Sure it's a servo? I went through almost every electronic part on a glitch (tail twitch) before I finally replaced the motor! There is also a lot of potential interference for the gyro too...

Anyway, back to the Ice box, I condensed this thread into a step by step tutorial and cOld has 'stickied' it in the tutorial section for easy access in case anybody wants to follow it!
http://www.laserpointerforums.com/forums/YaBB.pl?num=1222708267/0
Jay

 

[hydrogenman15]

I am very interested in the "peltier effect" now! I decided to google it and I realized that you can "stack" the Peltiers on top of one another and the temperature difference between the top and the bottom of the Peltiers would be more and more as you add more peltiers... Although as mentioned above the condensation would get WAY out of hand. :-/ Heres the link --> http://www.digit-life.com/articles/peltiercoolers/

I remember a link about "super cooling" a laser diode using something from a computer. I think the wavelength got down to about 640nm... Whats the limit for how cold the diode can get before it stops working? Is there any way to control the condensation?

--hydro15

 

[suiraM]

There are ways to control the condensation, yes. One of which being to cool the entire room you are in to below freezing, but that's hardly a pleasant solution, and may not be too kind on other things (and occupants) in the room.

As for how cold a diode can get, it is certainly possible to operate a diode at an insanely low temperature.

I had a much longer answer, but then I ated it:

Time. Money. Quality. Keep two.

Such summaries suffice.

 

[laserrod]

Just heat the output window/lense with the wasted heat from the LD circuit. Seal the laser up with a desicate pack(gel packet).
Keep condensation away from output.

Just helping.