Posts Tagged ‘ethernet’

Ethernet shield

July 8, 2012

After a long delay, I’m back to playing with electronics.

I bought an arduino ethernet shield from dfrobot (cheap, because it’s the old version that doesn’t have an SD card slot). I got it to work fine with the arduino Ethernet library. The only tricky bit was the MAC address: I tried using a random one, and the arduino would hang at Ethernet.begin(mac). But for some reason if I switched the initial hex digits to 00, then it worked. I ended up just adding 01 to the MAC address for my laptop.

After trying out the very simple examples that come with the arduino Ethernet library, I hooked up a temperature sensor to it, got an account at, and used the CosmClient example to log temperature data for my living room for a day. It was a bit too easy, so I don’t feel particularly accomplished. And the precision of the TMP36 temperature sensor I used (from the Sensor Pack 900 from adafruit) is rather crappy. It’s attached to an analog input and gives temperature in 1° increments.

I’m not sure what I’m going to do with the ethernet shield, but it seems like it’d be cool to be able to turn lights on and off via the web.

I ordered the data logging shield from adafruit, because I wanted to log the temperature inside my refrigerator, as Lady Ada had done. (I guess I should have just ordered the proper ethernet shield, which would have included ethernet and SD card access!)

The code for my little temperature logging project is on github.