Tutorial: Blu-Ray With TEC! - Step by Step

hugo999999 · Mar 4, 2010

hi, im making a similar build as this and was wondering if there was a minimum temperature a laser diode can run at? is it possible to kill it by getting very cold?

also does anyone know if the amperes going to a peltier need to be regulated or will it only draw how much it needs?

thanks

jayrob · Mar 4, 2010

Well, I don't know a lot about the peltiers, but I just went by trial and error...

I found that it is better to use a driver, because you can adjust the amount of cooling, depending on what power your diode is.

Very important to use a fan and heatsink for the peltier...

From what I have read, you can damage the diode if it gets too cold.

hugo999999 · Mar 4, 2010

my only problem with using a driver is that it would be have to be high rated as im using an external power source possibly. it could put out upward of 10amps... not sure if i should just let it draw that much current or attempt to find a smaller supply

hugo999999 · Mar 4, 2010

no problem, ive found a smaller supply which is 2amps which should be low enough. thanks for the help
hugo.

jayrob · Mar 4, 2010

Hope it goes well...

Make sure to show your build!

hugo999999 · Mar 4, 2010

lol i will... if it works haha :wave:

jayrob · Apr 21, 2010

Update:

Just put a 12X diode in my 'Ice Box' TEC build...

The build uses a Meredith mounting block, which has a 1/2" hole for the module, so instead of using a Meredith module (which does not have a 'pressed in' design for the diode), I made a 1/2" copper module so that I could have a pressed in diode.

The custom copper module is of course threaded for my 405-G-1 glass lens assembly.

I have it set at a fairly conservative setting for longevity...

350mA's / 480mW's

Here's a video of it cutting a wood match in half:

The blue light on the side is the Li-Po alarm. It changes colors as the batteries get lower and lower...

LiPo Alarm color code:

Bright blue - Full charge
Cyan - Very good
Green - Good
Yellow/Amber - Low warning
Red - Batteries low (70%)

Benm · Apr 21, 2010

Looks like a cool project!

One thing though: it seems the voltage regulators are bolted to the cold side of the TEC?

Gryphon · Apr 21, 2010

Looking great as always, i have no doubt that diodes gonna last a good long time in there

jayrob · Apr 21, 2010

Benm said:
Looks like a cool project!

One thing though: it seems the voltage regulators are bolted to the cold side of the TEC?

:thanks:

The 7805 regulators are adhered to the cold side of the peltier, but take a closer look at the pictures...

There is a piece of mica sheet for insulation between the peltier and each of the 7805 regulators. So the heat from regulators is somewhat 'shielded' from the peltier. (and their metal heatsink is 'up', with their own finned heatsink - isolated)

But I also figured that it would be ok for the 7805's to get a little cooling as well!

Benm · Apr 21, 2010

I'd put the 7805's on their own seperate heatsink, or on the hot side of the tec. I wasnt sure from the picture if the mica was a thermal connection or thermal insulation (its used for both depending on thickness).

The downside of having the regulators on the cold side is that you'll have to cool their heat away with the tec, using extra power, running the regulators even warmer, etc. Those 7805's dont need to be cold - they run perfectly fine when scaldingly hot, but will reduce output current/voltage if required to save themselves.

jayrob · Apr 22, 2010

Yeah... I didn't have a lot of room using two Li-Po batteries in parallel. There was room on the peltier...

So I used the extra space on the peltier to mount the regulators with mica sheet insulation, which also made it easy to mount the drivers as you can see in the picture...

And the 'hot' side of the 7805 regulators (the metal parts), do have their own heatsink (notice the black fins in the center), which is isolated from everything else.

The idea I had with the mica sheets, was for insulation. And I figured that the cooling to the module heatsink block would still be fine.

I tested it for 5 minute run times with a drop in temperature to the heatsink block/module...

So I'm pretty happy with the way it is working!

Hemlock_Mike · Apr 22, 2010

I didn't add TEC untill I went over 500 mA on a 12X !!!! Heat isn't the biggest problem when going to 1 Watt.

HMike

jayrob · Apr 22, 2010

What would be your guess for run time if...

The module stayed at the original ambient temperature? Or if it even dropped just a couple of degrees?

I know it probably would not be good if it dropped a lot in temperature. But if it stayed within a couple of degrees of the ambient temperature, would you think that the diode could be kept on for long periods?

That was the whole intent with this build... (and to have a separate driver for the peltier to be able to adjust it)

Benm · Apr 22, 2010

jayrob said:
And the 'hot' side of the 7805 regulators (the metal parts), do have their own heatsink (notice the black fins in the center), which is isolated from everything else.

The idea I had with the mica sheets, was for insulation. And I figured that the cooling to the module heatsink block would still be fine.

Ah right, didn't quite see that in the pictures before, but it seems fine like that.

By the looks of the heatsinking i'd say it would be fine for continous operation - or at least till the batteries run out

jayrob · Apr 22, 2010

I've got 2 X 1320mAh Li-Po packs in parallel...

So that means a total of about 2640mAh's capacity.

I would estimate that the entire build uses maybe 1300mA's or so. (fan, peltier, diode with FlexDrive, regulators, Lipo alarm)

So it should be at least 1 1/2 hours (possibly 2 hours) of operation before I need to charge the batteries...

I doubt that the Lipo alarm uses much, but it is nice, because the color of the light will change and let me know when the batteries need charging.

LiPo Alarm color code:

Bright blue - Full charge
Cyan - Very good
Green - Good
Yellow/Amber - Low warning
Red - Batteries low (70%)

Tutorial: Blu-Ray With TEC! - Step by Step

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