I tried to connect a LM35 according the 'instructables' http://www.instructables.com/id/Arduino-Temperature-Sensor-Interfacing-LM35-THE-EA/step2/Setting-up-the-Arduino-with-temperature-sensor/

I tried both the way proposed and +5 / Gnd switched. In both cases I get slightly fluctuating temperatures (around 300 degrees Celcius) and if I blow on the sensor it gets a bit higher temporarily so that seems ok.

However, after 10 seconds to a bit more, it is really hot and the Arduino stops working; cannot send sketches etc until it cooled down or disconnect some wires.

Am I doing something wrong or does it have another reason?

Update: I put everything in the box and one day later rebuilt it (somewhere else) and now it seems to work correctly. Now the temperature is steady around 23.0 (which is incorrect, should be at least a few less) but still it's more accurately than 300 degrees. I think yesterday I put the + and GND incorrectly, and the temperature was already so high I thought it still was not good when swapped around again.

I'm sorry for the responses below (still a newcomer in the Arduino world).

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    Seriously, 300C? And higher yet if you blow on it? Something is wrong; the ones I'm familiar with are in a plastic package and have 150C upper limit. I can't imagine them surviving - physically - a 300C environment. Nor you having such hot breath! :) I'd first check my A/D value -> temperature conversion, and second, the connections against the pinout, since you are observing "really hot". As a sanity check, about as hot as we can stand to touch is around 60C. And blowing on the device, unless it's cold, should cause a drop, not a rise. – JRobert Feb 28 '17 at 22:51
  • @JRobert I don't believe it's actually 300 degrees, and after blowing to 310 or so. I just noticed when I touched it, it was quite hot (didn't burn my finger, but also barely touched it). But even when the ratio of A/D / temperature was incorrect, I don't think it should get so hot (and make my Arduino behave strangely). With blowing I mean warm air blowing, so possibly the temperature was ' normal' but the values strange, but still the physical temperature was hot (touching it). – Michel Keijzers Feb 28 '17 at 23:00
  • Makes perfect sense. It - or something - is connected improperly such thattoo much current is being drawn, if the Arduino stops or heats to where it requires a cool-down. How about a photo of your wiring, and/or a schematic? And in the photo in the instructable I notice the Arduino is sitting on what looks like a foil bag. That's a short-circuit right there! – JRobert Mar 1 '17 at 0:18
  • @JRobert this evening I will do some tests (trying different pin layouts since I'm not sure what is correct, hopefully not blowing something, if not already done). Btw, I didn't use a foil bag, but everything on a breadboard. – Michel Keijzers Mar 1 '17 at 9:43
  • @JRobert Thank you for the answers ... it's working now (updated the answer). Pics are not needed since it's according to the 'book'. – Michel Keijzers Mar 1 '17 at 21:41

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