Temperature Sensor DS18B20 and producing some heat

Hello

I got two questions so: 1. Does someone have experience in using the DS18B20 Temperature Sensor? I tried measuring the Temperature in our fridge. It took over 20 minutes to measure the right temperature. Could the reason be that in the fridge is no Air that circulates around the sensor? Or is it something different?

2. I do need my Arduino in a very cold environment (-30C). I will put it into a Styrofoam but I have to produce some heat inside this case. I do use a 2s Lipo so how can I produce enough heat so that the Lipo is not freezing :) ?

Thx Geko

The DS18B20 is usually in a TO-92 plastic case. The plastic doesn't transfer heat all that quickly, although I would have expected it to react more quickly than 20 minutes.

There are heat-sinks for the TO-92 package - one of those may help make it react more quickly.

As for heating the inside of the container, see the thread on 7805 voltage regulators - you will get some self-heating of the arduino board since the regulator uses it as a heat sink.

In our balloon payloads we have used chemical hand-warmers, power resistors (large sand-filled jobs), and special peel-n-stick resistive heaters.

-j

Thx for the advise! I will check those Heat Sinks...

Geko

I have used DS1820s for years, with little hassle. I suspect there was something acting as a "heat capacitor" in how you had things set up. The heat sink idea is good, if you want to measure quickly changing air temperatures.... and of course, the DS1820 needs to be away from any "heat capacitor"s. You can get a smaller, SMT, chip, which is either DS1820 compatible chip or works in a very similar way, from several sources, one being EmbeddedDataSystems.com... DS1822Z, @$2. Beware shipping delays.