5W RGB Projector using 3 diodes

[planters]

Yes, I have. My current build based on what was available when I was assembling the quad red used G71's which are making 1W each at 1100mA @ -20C. This satellite's "clone" will use P73's and the first two I tested in my cold rig produced 1.18W at 1200mA.

I am not sure where the post was, but the results of the G71 were in the video I produced a few weeks ago.

[steve-o]

Ok, well the blue is taken care of, the red almost.. what size peltier junction do you recommend? .. and the green. Dohm y'all say ? Hmm. Are they good? ..Expensive? Seems anything green over a watt takes a lot of green :]

[planters]

I bought my DOHM from ultra lasers in Canada. The 1W is smaller than my Vashio 1.5 W and also produces 1.5 W (it is seriously under-rated). It is quieter than the Vashio and the beam specs are very close. The Vashio produces a 2mm beam with approx 1.5mrad divergence, but the spot is irregular; it looks a little like a peanut. The DHOM has the same 2mm beam with a nice round , but slightly higher divergence beam at 1.8mrad. The DHOM was a lot cheaper.

With my quad and a 100mm x 150mm cold plate I am using a single 60mm x 60mm TEC rated at 24V x 24A which I run at 12.5V.

[CDBEAM]

Yikes Mr.P.....or should I say " Mr FREEZE "...that's 300 Watts of cooling power....Likely fry an egg on the other side !!! Lots of heat to get rid of !! But oh, what results !! That is a TE on steroids !!! I will be experimenting with a 192 Watt( 40mm x 40mm ) controlled by a 1/16 DIN Aubers Instruments Temp. controller. Still setting things up !

P73 LD MTTF is still a wildcard here !! BUT the simplicity of a Dual is a huge draw !!

As usual, you are on the forward edge of the " Wave Front " THANK YOU !

BUT...Can you Eat it ??? hahaha

Beam Out

[planters]

No. The TEC acts as a resistor and so that's 12.5V x therefore 12.5A; about 160W. If you are going cold then the delta T with a change in drive voltage is pretty small and the inertia is large. So, for example once at equilibrium at -20C at 12.5, if I suddenly increased the V to 16 then the temp will settle in at -25 five minuets later and the output will change by about 3%. So, I just pick a voltage on a switch mode PS and leave it. The heat input from the diodes is a relative small component of the heat load and so little temp. change from stand by to full modulation. As a result, no feedback and no control. It's pretty simple.

I'll have my spatial filtering video of these diodes done soon. And re. "wave front" there may be something there too. We'll see.

[steve-o]

/.. the output will change by about 3%. So, I just pick a voltage on a switch mode PS and leave it. The heat input from the diodes is a relative small component of the heat load and so little temp. change from stand by to full modulation. As a result, no feedback and no control. It's pretty simple.

Yeah! That's what I'm talking about. No controller to have to fool with; feedback loops and all that mess. Thanks for that! I've found that simpler is better on a lot of things.

[steve-o]

Nothing against the Dohm, but,
as far as the green goes, I'd rather have this:

Than this:

just because I could run it off of a centralized toroidal multi-secondary transformer/ps that would power all 3 of the lasers, and just add small driver boards. Simpler, less space consumed, uncluttered wiring. My .02 ( The core pictured above is a pic from ebay, is 500mw and 320 usd. I'm sure there are 1.5W cores somewhere.)

[steve-o]

Sorry for the triple post. Planters, or everyone, where to get a good Peltier? I've looked at ebay and there's a lot of them, but questionable quality on some.. ?

I'll have my spatial filtering video of these diodes done soon. And re. "wave front" there may be something there too. We'll see.

Looking forward to that vid.

[planters]

I would go to Custom Thermoelectric or TEtech. I've ordered from both. They are comparable in performance and cost and the choice usually comes down to the availability of a particular stock model. I've used Melcor in the distant past, but if I remember correctly they tend to smaller sizes.

Core? Can you give more information?

[CDBEAM]

Steve, See


Sure-Electronics 192 watt TE on Fleabay @ 20 bucks !!. I have tried it out....works good !! Nicely made !!


Yea...I have seen 500mW offered for a core....not 1~1.5W !!! Maybe this is offered somewhere ???? I have not seen it !!

BEAM OUT