Chronodot Library for Arduino

Posted 2011.04.09 22.44 in Computers/Internet/Technology by Stephanie

When I was working on my Thermostat project, I came across the Chronodot RTC (real time clock) and decided it would be the perfect choice. Not just because it’s incredibly accurate, but because it provided both time and temperature readings in a single package. I could have used another RTC such as the DS1307 which is less expensive, but then I would have had to use something else for reading the temperature.

The only thing about using the Chronodot to get temperature readings was that there wasn’t an Arduino library that could get me that information. The Chronodot communicates using the i2c protocol, and as I hadn’t used it before I was hoping to find some examples and a usable library. Fortunately it’s compatible with the DS1307, but of course that library has no reference to temperature as the ‘1307 doesn’t read the temp.

So using the ‘1307 library as a starting point, I expanded it by adding two new readings to it: temperature, in both farenheit and celcius.

The library includes an example sketch. If you’re familiar with using the DS1307 with an Arduino then the Chronodot library will be an easy drop-in replacement. The time features are unchanged, I’ve just added the two temperature readings so they’re available within your sketch.

Click here to download the library:


  1. Dek says:

    Do you host this in online source control?
    I just upgraded to Arduino 1.0

    This lib is incompatible because Arduino 1.0 changed “WProgram.h” to “Arduino.h”

    I just figured if you had it on git or something i could send you a pull request.

    1. Stephanie says:

      Hello Dek,

      Actually I just downloaded Arduino 1.0 today and was about to get to work on updating this.

      It’s not on GIT — though it should be — it’s just that I’ve never got around to learning how to use all those fancy tools… I’m not a real developer, I just play one on the internet.


  2. Stephanie says:

    Update – I’ve just updated the library to work with Arduino 1.0 while being backwards compatible to the older IDE.

    Get it here:

  3. rick says:

    is there anyway to set the time,date,year

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