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Arduino: Reading the SHT15 temperature/humidity sensor

Filed under: Arduino,Hacking — jet @ 14:04

Ok, this was a bit more fun and geeky. The SHT15 is a temperature/humidity sensor made by Sensirion. I bought mine from Sparkfun, and at $42 it’s a bit pricey, but it’s pre-mounted on a breakout board saving me a nasty soldering job.

The SHT15 isn’t as fragile as a lot of other electrical components — you can get it wet, put it in the sun, etc. I’ll probably just mount it at the end of some very long leads and not bother putting any sort of protective case on it.

Being the rocket scientist that I am, I didn’t download the specs until I decided to actually write code. Turns out that the SHT15 uses a serial protocol developed by Sensirion; but they were kind enough to post some sample code for the 8051 so it wasn’t too hard to get working on the Arduino.

If you’re trying to get this working, take a look at my Arduino sketch. Writing code to read serial protocols using clock and data pins isn’t for the newcomer, but it isn’t terribly difficult if you know a bit of C, bit-wise operations, and have sample code to reference along with the timing diagrams.



  1. I’ve finally had success in conncting the Arduin Diecimila and SHT15 sensor.
    Arduino Bluetooth needs, however, somewhat tricky trial-and-error, reset-button and uploding timing.
    One question: Does the Arduino allow more than one SHT15 connection using the sort-of two-wire interfacing?

    Many thanks,


    Comment by Bryan — 2008/07/21 @ 05:59

  2. I don’t see why you couldn’t have more than one SHT15. You’d have to put them on different pairs of pins, obviously, and it would be tricky reading them simultaneously. But reading them in round-robin fashion shouldn’t be terribly difficult.

    Comment by jet — 2008/07/21 @ 10:16

  3. Thanks, jet.

    As you have suggested, the round-robin reading will be fine for my purpose.

    Thank you again for your kind comment.


    Comment by Bryan — 2008/07/21 @ 17:50

  4. On the round robin way you can share the sck signal and for the 2nd one you need only 1 extra digital line.
    I use a led with a resistor to ground, on the sck signal, to monitor the sht-15 status.

    Comment by Jkutianski — 2008/08/07 @ 22:16

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