New project inquiry

[cyberhedz]

Me and a co-worker are planning to develop a multi-diode laser box, and I was curious about the cooling to utilize on such a venture. We are planning to have a 6X blu ray laser, around 150-200mW, a 20X burner red laser, around 250-300mW, and a 125-150mW green laser, safety switches, and (3) 3.6V li-ion batteries.

Question is, should we use fin heatsinks with fan cooling in the box or is there a better alternative to keeping all 3 at a performance temperature?

 

[Flaminpyro]

I would go with the heatsink and small fan or fans you can get some very small 5 volt fans now days and that would be the less expensive way to go IMHO. LM7805 voltage regulators are cheep, whats the option a current sucking peltair. have fun !

have a happy and safe 4th Pyro... :eg:

 

[nikokapo]

At that power you could just go with passive cooling. However if you're gonna use it for long periods then active cooling with a 40mm or 80mm fan is recommended. I'm not gonna say you should use TEC cooling because I don't think it's worth the money for what you're gonna use.

 

[Eku]

For very short time (<3 minutes) = no heatsinks.
For short time time (20> minutes) = small heatsinks.
For average time (3> hours)= average heatsinks and 1 fan
For long time (7> hours) = Large heatsinks and 1-2 large fan(s)
For VERY long time (24> hours) = large heatsinks, 2 large fans and 2 large TEC's.

What do you want ?

 

[Jaseth]

I agree with both pyro and niko - a nice, large finned heatsink is enough for normal use, whereas for extended use I would recommend a small fan. 40mm should be more than enough (80mm moves a huge amount of air). TEC is more expensive and probably not going to do a better job of cooling.

Also keep in mind the direction of the fan - depending on the shape of the fanned heatsink you may want to suck away heated air rising to the top of the unit, or blow cool air into the heatsink. Both methods work, but there is usually one more logical for a given project.

Furthermore, if you should ever construct an enclosure which uses a fan, make sure there is a throughflow of air to all components, meaning the air which the fan moves cannot just be pulled in or exit just beside the fan, but has to travel throughout the enclosure and cool everything down. Two fans which suck in air, or two which blow out air will not do a lot for cooling and just create vacuum or pressure. Likewise a single fan needs ventilation holes to push out old air or pull in new air through.
You can find good information on www.laser-man.co.uk

Good luck!

Seb

 

[cyberhedz]

damn, i like this board already, fast, intelligent, and helpful replies. I plan on average to run at 15minutes or less, and luckily was planning on adding 1 or 2 40mm fans to the case anyways, good to know that 1 may be all i need, i thought about using a peltier but i decided against it as I have no way of eliminating the risk of condensation inside the case. I am also assuming 10.8V is enough to drive a laser and a fan for 15 minutes, the batteries are 880mAh if I am correct.

 

[chipdouglas]

I don't think 3- 3.6 volt batteries will be enough. you would need that for each diode unless you use 3- lava drivers. just my opinion....my fact

 

[cyberhedz]

yes, sorry I didnt explain better, each diode will have its own driver and teh output driver would be selected by a switch on the main housing

BATT-->master switch, turns fan on--->key switch---> 3 position switch with each position to a driver and diode. red tuned to 380mA, green 150mW(o-like), and 100mA for the 803 blu-ray diode, which I plan to upgrade later to a 200mA 6x diode.

so, if my math is correct, i may have to bump the power since most fans are 12V, and the red 380mA is nominal at 9V, any recommendations?

 

[chipdouglas]

are you looking for for this to be hand held. or could you use it in a plug in application? if you can use it in a plug in application. just use a power supply from a computer. it gives all the volts you need. 12, 5, 3.?

 

[cyberhedz]

somewhat portable, we're going to use a small or medium size project box from radiocrap

 

[rog8811]

Are you wanting to combine the beams? If so look around for jayrobs 7 colour laser tutorial or go to my website for mine (link below)

Regards rog8811

 

[cyberhedz]

no, individual beams, selected by a switch, and i'm in luck I found some 5V fans that will work, so i'm good at 10.8V again

 

[chipdouglas]

can you describe the enclosure/host you want to use. nm. you said a radio shack hobby box. will the lasers ever all be on at the same time? if not you could simplify it all and use just one driver. and switches.

 

[rog8811]

you could simplify it all and use just one driver. and switches

Not worth the hassle as you need to have any capacitors directly mounter to the LD's and you need different current for the red and b-r LD's.
The drivers are so cheap these days

Regards rog8811

 

[cyberhedz]

exacly, at 12 a pc, its fine and i can fine tune each one as I go, right now i'm trying to draw up some schematics for a on/off switch with indicators but can't for the life of me remember how to make a like cut off when power is still applied, i know its a resistor, but i dont remember where, lol. to sum it up for the key, i want red LED for off and light the green when its on, but its a SPST key switch

 

[rog8811]

You need a 3 wire, tricolour LED one wire is common other 2 for the red and green. put a limiting resistor for each colour then you can fine tune the brightness of each.

Regards rog8811

EDIT...I have done a picture, you need a master switch to have an off/off position If you are using a common supply you can just join up to the other 2 switches the same as the one shown.
Check that the common on a tri-colour LED is neg....I cannot remember
Edit my edit.... I have checked, drawing is correct.
RED GREEN 10MM TRICOLOUR LED , 2pcs on eBay (end time 06-Jul-09 14:22:27 BST)