TEC project

[MechEng3]

OK this is 20 or so miles better than what I had in mind to have! If there are any kits available , I would like to get at least 3 of them! Please let us know the status of this as it is exactly what is needed. This would allow me to finish up the 1/2 watt green project....all the optics and housing are completed. The next one would be used to cool 4 = 150mw C mounts on a common TEC, 635nm wavelength. Should work out nice. Let me know when you get a chance.......cooling mode only would be just fine as my diode mount shares heated surfaces for KTP.

[uk-laser]

Yikes! It seems like there was more interest than I anticipated.

I am all out of bare boards - the prototype board build was a fairly small batch.
I have 5 (almost) assembled units (I just need to solder in the PCB terminal strips) but I need 2 of the D4Chills myself.
The other 3 I guess are up for grabs.
Price for an assembled board would be £30 GBP, Peltier (31couples, Imax=5A Vmax=3,7V Qtot=11.5W, 15 x 15 x 2.9mm) £5 GBP each, 10k thermistor £1 GBP + shipping at cost + £0.50.
If several people want to go down the build it yourself route I could order another batch of boards in which case bare PCBs would be £10 GBP each including shipping.

BRs
Robin

[andy_con]

i would buy a complete one off you robin if they were for sale

[Lasernerd]

I would also like to get the last two completed units also

Mark

[uk-laser]

Sold out.
PMs sent.

[dave]

Semi related:

What thermometer's doe you guys use? I bought a infrared non contact one, but im not sure it works the best... Hehe, maybe I need a laser thermometer

[frank_1257]

I thought it would be a nice touch if someone , or a group, here on the forum would be willing to work towards creating a simple, yet effective TEC control as a project. There are a couple of really nice diode drivers available from members.....hat's off to you! I have tested and like all of them . It seems a LM317 based regulator and a TIP120 could be set up as a thrifty TEC device with a 10K thermistor. Maybe an op-amp to switch it on and off? Many possible ways....just trying to get a nice project in the works that I know lots of people can use....even for other than laser applications......shudder the thought. Anyway what do you think? Any takers....cohorts on a device of the like? Willing to donate parts,time when I can, and funding help. Any takers? Maybe call it "The PL-Cooler"? Tired of the balky PID units that need to be fed 120VAC

I am on a tirade to experiment with Do It Myself laser design and construction most high power lasers can easily require 3 different TEC controllers I have just had maxim send me 20 free samples of their max 1968 and the higher powered 1869 the only problem is that they are tiny ssop packages and you will need perfect eyes and nerves of steel to solder or a good stereo microscope, look at: www.maxim-ic.com/quick_view2.cfm/qv_pk/3377

ok these are great with low wattage 2 or so amp peltier applications to cool small lasers and heat cool ktp yvo4 lbo etc.

For your larger lasers applications you are going to need an mosfet h-bridge for producing bipolar control and a chip like Linear IC's LTC 1923 it has capability of being digitally controlled and is much more versatile with a dual supply for high compliance voltage Peltier applications. Linear has a compact litlle developer board you can buy or possibly talk a Linear sales rep out of they will give you bare IC's easily but not so with the eval boards unless they think you will buy 500-5000 units annually. here is the eval link:www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1003,C1263,P15954


Now here is a simple to use IC that might be socketable from Analog Devices:http://www.analog.com/static/importe...ts/ADN8831.pdf

This one looks promissing.

A word of forewarning tuning most of these TEC controllers is somewhat involved time wise it's not just setting a temperature setpoint, but also gain, time constant, etc. it can take a little time to do the math and tweak 3 25 turn pots to get things just right.

I have bought several high power single ended tec controllers from TE Technologies and they ran about $100 each, they are about 1.5x2 inches in size.

[p1t8ull]

What thermometer's doe you guys use?

Nothing flashy here, just DMM that does temp with a "K" type thermocouple. It does have an annoying "auto off" feature though, so no doubt it'll need extracting from the wall and replacing at some point

[frank_1257]

One of the problems you will run into in any scenario using peltiers or monitoring temperature is going to be with getting an accurate temperature reading while a non-contact Ir thermometer seems nice or thermocouple temp probes your best bet is ALWAYS going to be to make sure you have some kind of sustantial piece of copper or aluminum on either side of your peltier and drill a small hole in it as close to your mounted cooled device as possible and place a glued( special thermal conductive epoxy) thermistor. Any surface contact measurement probe may be off bt 5-20 Deg. Cent. you can cook off your device and never measure it is running so hot. Another issue is failure to have good thermal contact with your cooled device silicone grease or even indium foil is a fair-poor heat conductor but better than air. Any air voids between your cold and hot plates of your peltier and your device and heat sinks or water cold plates can cause disaster some thing as simply as using super fine valve lapping compound or wet sandpaper to lap your devices together can make all the difference in ensuring good heat transferance and low thermal resistance. Melcor has SEVERAL WONDERFUL FREE MANUALS for download at their website.

[frank_1257]

One of the problems you will run into in any scenario using peltiers or monitoring temperature is going to be with getting an accurate temperature reading while a non-contact Ir thermometer seems nice or thermocouple temp probes your best bet is ALWAYS going to be to make sure you have some kind of sustantial piece of copper or aluminum on either side of your peltier and drill a small hole in it as close to your mounted cooled device as possible and place a glued( special thermal conductive epoxy) thermistor. Any surface contact measurement probe may be off bt 5-20 Deg. Cent. you can cook off your device and never measure it is running so hot. Another issue is failure to have good thermal contact with your cooled device silicone grease or even indium foil is a fair-poor heat conductor but better than air. Any air voids between your cold and hot plates of your peltier and your device and heat sinks or water cold plates can cause disaster some thing as simply as using super fine valve lapping compound or wet sandpaper to lap your devices together can make all the difference in ensuring good heat transferance and low thermal resistance. Melcor has SEVERAL WONDERFUL FREE MANUALS for download at their website.

Another thing to watch for is that a thermistor device can quickly often times disappate heat through its wire leads it is often recommended by many TEC controller mfgs to use aluminum foil tape to fold down the leads next to the cold plate and tape them in place to insure accurate readings.