Ice is Nice....

[mixedgas]

Mudds women ..lol CDB .. good one .. they need to put trek orig back on tv one more time ,, even tho I've seen them all 15 times over .. still can't stop watching ..

Man, where do you live? Trek runs all over here on the over the air and cable. No problem at all to get the first Trek.

Steve

[macona]

A couple questions...

1.) Has anyone established a practical lower limit for TEC cooling? I know they can be stacked for a greater temperature differential, but how low can they go?

My Quantix camera for my telescope drops the sensor down to -30c and it is peltier air cooled. I think it might go lower using the optional water cooling loop.

[kiyoukan]

no its not going to keep 1F or anything but it keeps +-3F and for the price of about 2$ not bad.
But maybe that was due to my thermal loads also being somewhat constant with a decent thermal mass to better help balance it.
but you could do something very similar for only a bit (2$) more but use an 8pin micro that would get you very accurate results.

[kecked]

why not use a micro to put out a pwm rather than the 555. The use an a/d input to read a thermistor voltage. Have the pwm drive a fet. The code would be maybe 20 lines max.

Had a second idea. Use a second a/d or even i2c to read a humidty sensor. That way you can stay out of condensation problems too. More code though. BTW if you just use the humidity sensor and you have a sealed chamber it would be the same as measuring temp down to 0C.

http://www.liquidware.com/shop/show/...erature+Sensor

https://www.sparkfun.com/products/10239

[kecked]

If there are enough people intersted in this I'll write the code for a PICAXE in BASIC so everyone can play with it. I'm going to do it for a weather station anyway. There is no reason you can build fan controler with it as well to turn you cooling fans for the rest of the projector on and off as well. You can even monitor your driver fet/tramsistor temps and start a fan or tec. Once you have the basic code(pun not intended) its easy to change. If you don't ant to wait for me I have to say if I can code it a monkey can code it. I'm code challenged. Try these picaxe or basic stamp things. They are really easy.

https://www.sparkfun.com/products/11295 this one has a built in alarm that can be used to drive something.

[kiyoukan]

http://playground.arduino.cc/Code/PIDLibrary
but doing it for a pic would be cheaper, but i know alot of us use arduinos.
I do think someone should design a cheap pcb with a good bom and post it up.

[steve-o]

Man, where do you live? Trek runs all over here on the over the air and cable. No problem at all to get the first Trek.

Steve

I live in southwest VA (way out in the sticks) and have directv. No cable out here. Maybe Trek's on sometime, I just haven't searched for it. I'll do that today! Thanks for the idea Steve

[macona]

You might look at a ADN8831 from Analog, it is a dedicated TEC controller.

[planters]

I am using indium foil for crystals that need to be scrupulously clean such as the vanadate and the KTP and for the LN2 project where greese and epoxy will fail. Otherwise, the glue works well for these more practical interfaces.

In closing....the ONLY thing I see missing from your Dream Shop are.......The Robot Girls... formerly owned by " Harcort Fenton Mudd ".....from the original Star Trek Series !!!
See the pic of Eric's real Laser Lab Assistants !!!

These lasers may represent the last few significant projector based laser applications I will be doing for some time and the boys and I are looking seriously at the stuff coming out of Boston Dynamics. Wile not Mudd's, they look like fun. We'll see.

[Stiffler]

I am excited at the prospect of more power & greater efficiency from TEC (or cryo) cooling, as it could mean less diodes, and less complicated setups. That being said, I am drinking beer, so keep that in mind. Anyway, I have a question/concern.

Is there a way to limit ld current based on temperature? For instance, Planters was able to get about 4X the power when using dry ice, but I imagine once the dry ice is gone, the diode dies; would there be a way to avoid this?