Need Advice - DIY Sea Turtle Nest Temperature Logger

Dallas did some sensors which were for food shipment temperature checking etc.

The battery  lifetime is a function of the sample rate so you cut the cloth to what can be achieved

Dallas thermocron DS1921G http://www.maximintegrated.com/en/products/comms/ibutton/DS1921G.html/tb_tab0

Should be what you want and it's environmentally sealed as well

Mike I agree that the particular ibutton  type is marginal to his alluded to spec's the question is does he really need that accuracy or is this what he assumes he needs also any build been suggested would need to be calibrated and proved to in the original spec even if the original components promise this.

Further more you could pick a different model (more accurate)if they exist and you could calculate whatever offsets these units have via a process of calibration so you can adjust results according to this process. Also 1 deg c is over the full -40-85c so over the normal "Turtle" range this is likely to be much less.

Any way as you can see they are close enough to initial spec to buy a few and evaluate !!

The other issue was the price - (I remembered there was a big problem - it just eluded me for  a while today)

http://www.embeddeddatasystems.com/DS1922L-F5--Thermochron-iButton-40C-thru-85C_p_98.html

10 - 24 off, $46 which was where the OP came in - total budget about $500.

I don't quite know waht happened to iButtons - seemed a nice idea but it's fairly obvious that little or no development has been done on them for years. I designed a product with a built in reader once (about 12 years ago).

MK

The iButtons are used a lot in retail particularly pubs where they need to identify the bar person so they can run multiple tallys.

Even in the UK  the price is more like $20 should be able to get 2/3 that some where else

Temperature Logger Ibutton Ds1921g f5 | Rapid Online

The iButtons are used a lot in retail particularly pubs where they need to identify the bar person so they can run multiple tallys.

Even in the UK  the price is more like $20 should be able to get 2/3 that some where else

Temperature Logger Ibutton Ds1921g f5 | Rapid Online

That place sounds expensive ...unusual that a US specialist is like twice the price of a UK general stockist!

You have to compare apples with apples

http://www.embeddeddatasystems.com/DS1921G-F5--Thermochron-iButton-40C-thru-85C_p_5.html?gclid=CIffuuqI974CFa3LtAodRm0AKA

$22 each = £12.94 (@ 1.7:1 exchange rate)

MK

Yep that's more like it.. I think this thread has gone stale ..it would be nice to get some input from Mr Turtle Man         !!