Open Can with TEC (20' Match Light Video pg. 5)

[jayrob]

Open Can with TEC (20' Match Light Video pg. 4)

Update: I have a 12X blu-ray/FlexDrive version of this build here:
http://laserpointerforums.com/f51/tutorial-blu-ray-tec-step-step-37239.html



I've been talking with Gazoo about his open can diode that he has run at currents up to 600mA and measured at up to 350mW with cooling! Wow!! So, I am off to a great project here and thought I would 'show as I go' if anyone is interested. This starts with an open can diode harvested from a Pioneer 112D 18X DVD from Newegg.com. (around $29)

Gazoo told me that He is currently running two AMC7135 drivers (one for the LD and one for the peltier) which supplies 350mA to each. Per Gazoo, this gives an output of 240mW! Wow again!

My idea is to have two DDL drivers so that I can have complete control over the LD current as well as the peltier. In my mind, I figure I would be able to 'fine tune' the cooling depending on what current the LD is running at.

Here's a picture of what I've got so far...

My plan is to mount the peltier onto the bottom of an aluminum box and use the box as the heat sink. I will make sure the module has clearance between its outer case and the box as it sticks through. If I can get this thing 'dialed in', then maybe I can even put the lid on the box. (I'm picturing a lid with some slots milled into it for ventilation if needed)

Anyway, more to come...
Jay


Edit: Here's the 20' match light video...

 

[Da_Dude]

Re: Open Can with TEC

Cool!
Good Job so far!

 

[Things]

Re: Open Can with TEC

Nice work!! If you decide to use a box as a heatsink, i think you will need a fan of some sort, or the box will have to be huge to dissipate the heat.

 

[Benm]

Re: Open Can with TEC

You will probably need more than just the box to cool the hot side of that peltier, unless the box is really thick and large. You could use a CPU heatsink plus fan or something like that.

One thing i notice: Did you thermally couple the LM317's to the cold side of the peltier? If you did, you really should change that since their heat will increase the demand on the tec considerably, and serves no purpose (LM317's can run hot just fine).

Btw, is that block from meredith, and if so, which one exactly?

 

[jayrob]

Re: Open Can with TEC

One thing i notice: Did you thermally couple the LM317's to the cold side of the peltier? If you did, you really should change that since their heat will increase the demand on the tec considerably, and serves no purpose (LM317's can run hot just fine).  

Benm, I did attatch the 'cooler' side of the LM317s to the peltier but mostly because it was a good solid place to mount the circuits. I was planning on having some other heat sinks arctic silvered to the metal part of the LM317s when it is all said and done. I don't think too much heat goes to the 'front' (or in this case, bottom) side of the LM317...at least not to the touch during testing...

Btw, is that block from meredith, and if so, which one exactly?

Yes, this block is from Meredith, the difference is, I put a set screw on top so that it would be an easy thing to remove the module if I need to replace the LD. Here is the link to the Meredith part:
http://www.mi-lasers.com/cgi-bin/sh...hstart=0&template=Templates/SearchResult.html
Their site shows a different picture, but that is the part number I ordered...

P.S.

You could use a CPU heatsink plus fan or something like that.

Do you have any links for a CPU heatsink with fan? I've got a few ideas floating around inside my head about how to power this set up and could set it up for a fan as well...One thing I am considering is a 7.4 volt Lipo battery pack...any thoughts there?

I would be very happy if I could get a 2 minute duty cycle at around 400mA without a fan...and hope for 3. Gazoo, if your out there, what are your thoughts?
Jay

 

[Benm]

Re: Open Can with TEC

Yes, this block is from Meredith, the difference is, I put a set screw on top so that it would be an easy thing to remove the module if I need to replace the LD. Here is the link to the Meredith part:
http://www.mi-lasers.com/cgi-bin/shopper.cgi?preadd=action&key=LDC-MB-1& reference=/cgi-bin/shopper.cgi%3Fsearch%3Daction%26keywords%3Ddiode_optics%26searchstart%3D0%26template%3DTemplates/SearchResult.html
Their site shows a different picture, but that is the part number I ordered...

The description is a bit vague... does this $5 block also have a mounting hole for the diode, and if so, is it 5.6 or 9mm? Or is it just a big block, where you have to add a complete module like these?

http://www.mi-lasers.com/cgi-bin/sh...hstart=0&template=Templates/SearchResult.html

I don't think too much heat goes to the 'front' (or in this case, bottom) side of the LM317...at least not to the touch during testing...

That's probably okay as it is... from the picture it looks like there is some thermal compount in between.

Do you have any links for a CPU heatsink with fan? I've got a few ideas floating around inside my head about how to power this set up and could set it up for a fan as well...One thing I am considering is a 7.4 volt Lipo battery pack...any thoughts there?

Not really, i guess the easiest place to get a cpu heatsink with fan is just a local computer store. You don't need anything fancy, a model for a 5 year old processor will do just fine. You could ask if the have any obsolete ones you can take for pennies.

I think the cpu fan usually runs from 12 volts, and it will work from 7 volts too, just a bit slower. You dont need it at full speed though, you're only putting a few watts of heat into the cooler, and it was intended to handle tens of watts.

 

[jayrob]

Re: Open Can with TEC

The description is a bit vague... does this $5 block also have a mounting hole for the diode, and if so, is it 5.6 or 9mm? Or is it just a big block, where you have to add a complete module like these?

Benm, check this page:
http://www.mi-lasers.com/cgi-bin/shopper.cgi?search=action&keywords=diode_optics
The mounting block in my pictures is the one that says 'mounting block for LDC'. It is made to fit their LDC modules, which are made for 9mm diode cases. If you want to mount a 5.6mm LD, then there is the adapter shown on the left side of the page. But again, I did modify the block just by putting a different set screw location...
Jay

 

[Gazoo]

Re: Open Can with TEC

Jay,
It looks very nice. You will not be powering the peltier with its full power...remember we went over this. But since everything will be enclosed, I agree with the others you will be much better off with a fan. I got mine from all electronics:

http://www.allelectronics.com/cgi-bin/item/CF-269/220/5VDC_45MM_COOLING_FAN_.html

These are 5 volt 220ma fans. You can use a standard 5 volt regulator to run them. They have lots of fans for reasonable prices. So please check out all of them.

It looks like the pots and resistors you are using are .5 watt. Remember to calculate the power, take 1.25 * the current. You will need higher power ratings for the pot and resistors if you plan to drive either the diode or peltier over 350ma's.

 

[Krutz]

Re: Open Can with TEC

i agree, it looks great so far!
i think one of my next ones will be similar.. those infamous open cans, and peltier-action!

all in all, we are talking about a max of 10 watts, propably much less. you could for exampe install the cpu heatsink on the hot side, and everything inside the box. without holes whatsoever. the diode will be cool, the heatsink will be hot, and that high temperature difference will be effective enough to give off the heat by simple convection inside and then over the box. of course it has to be a metal box then, with some space all around the module/heatsink, and nothing covering the box, especially the top side. the bigger the box, the more surface. of course, some holes on top would be even better, and the fan outside even more. but its not absolutely necessary, and i would like the idea of a hermetically closed laserbox.

the best option for a tec would be a temperature regulator of course. it wouldnt have many elements, would be small and cheap too. and would regulate the temperature exactly, no condensation when the laser is off, no overheating when the laser is full powered for some time. that would be the way i would try, if you acnt find any circuit ask me, and i'll look. have nothing more than google too, though.

anyway, more pics, looks great!

manuel

 

[wooooooolazer]

Re: Open Can with TEC

be careful about the metel part of those regulators touching the block the diode is in, that will make a nice poof since the metel on them is connected to positive and the negative of the diode is connected to that block, unless the block is painted then in that case i guess the it wouldnt be conductive.

..lazer... ;D ;D ;D

 

[jayrob]

Re: Open Can with TEC

the best option for a tec would be a temperature regulator of course. it wouldnt have many elements, would be small and cheap too. and would regulate the temperature exactly, no condensation when the laser is off, no overheating when the laser is full powered for some time. that would be the way i would try, if you acnt find any circuit ask me, and i'll look. have nothing more than google too, though.

anyway, more pics, looks great!

manuel

This sounds awesome. However, I don't know how to build something like this so, I would need detailed instructions...

be careful about the metel part of those regulators touching the block the diode is in, that will make a nice poof since the metel on them is connected to positive and the negative of the diode is connected to that block, unless the block is painted then in that case i guess the it wouldnt be conductive.

..lazer...    

Thanks for that warning...yes, the module and block will be isolated...

It looks like the pots and resistors you are using are .5 watt. Remember to calculate the power, take 1.25 * the current. You will need higher power ratings for the pot and resistors if you plan to drive either the diode or peltier over 350ma's.

Well, the resistor is 1 watt, and the pot is 1/2 watt. I am hoping you type back and say something like...'that should be fine then Jay'...otherwise, I'll have to change the pots. I am also thinking about maybe instead of a fan, maybe using arctic silver and putting a 1/2" thick aluminum block (same L x W as  the box) as a pad to mount the box onto. I am only trying to get 2 or 3 minute of duty...What about this idea?
Jay

 

[jayrob]

Re: Open Can with TEC

Jay,
It looks very nice. You will not be powering the peltier with its full power...remember we went over this. But since everything will be enclosed, I agree with the others you will be much better off with a fan. I got mine from all electronics:

http://www.allelectronics.com/cgi-bin/item/CF-269/220/5VDC_45MM_COOLING_FAN_.htm l

Hey Gazoo, thanks for that link. Are you using the 6 AA rechargeables to power everything including the fan? Also, if I go with a fan, shouldn't I also have a heatsink with fins? Gazoo, if it's not too much trouble, hook me up with the links to the 5 volt regulator you talking about as well as possibly a heatsink...
Thanks,
Jay

 

[Krutz]

Re: Open Can with TEC

here i have found a temperature-regulated lm317 driver, suitable for peltiers:
http://www.modding-faq.de/index.php?artid=507
its german, but anyone should be able to read the circuit diagram ;-)

it is based on a lm317, and will regulate the voltage by temperature. that should work for peltiers. didnt play with neither of them though. you can regulate some offset/limit/rate through that pot too.

manuel

 

[Gazoo]

Re: Open Can with TEC

Jay,
I am using a 9 volt power supply to power everything, but I have not really needed the fan since mine is not enclosed. All I can say is try it and see. With 1 to 3 minute duty cycles, you might be able to get away without the need for one. But definitely the hot side of the peltier should be mounted to a heatsink with fins.

Radio Shack has 5 volt regulators.

http://www.radioshack.com/product/i...igkw=regulator&kw=regulator&parentPage=search

But if you have an extra 317 you can use it to regulate the voltage to 5 volts. And you can find the schematic by searching google.

As far as the pots, sorry but you can't argue with ohms law.

 

[Benm]

Re: Open Can with TEC

If you want to use and enclosed box, i'd recommend using a heatsink, but also some holes on either side of its fins, and a fan on one side. This creates a wind tunnel of sorts, allowing very effective cooling in a compact case. A similar approach is used in many laptop computers.

 

[wooooooolazer]

Re: Open Can with TEC

Be sure to not give the peltier more than 5v, any voltage above that and it will alll be changed to heat not to cooling ability, with mine it can run on 5v for about 3min before the heatsink will start to get warm.

...lazer... ;D ;D ;D