I am trying to have a green thumb. Right now, it is more of a pale yellow with a hint of orange. One thing I thought about doing was a temperature logger for plants that I'm starting and will be transplanted outside in mid-April, after the frost season ends in this area.

I initially thought about using an Arduino, but connecting the Arduino to my network would have required me to buy an Ethernet shield or a Wifi shield, both of which are quite expensive.  I happen to have a USB wifi adapter hanging around and a Raspberry Pi that wasn't being used.  Match made in heaven!

So the first thing I did was go search around on the Internet and found something from Adafruit that included source code and a hookup diagram for a DHT22 temperature and humidity sensor. Mine is an RHT03, which is similar.

2013-02-24 01.50.10

I did find that my RHT03 does not run with 3.3v, so I changed the power rail to 5V, and viola!

The next thing I looked at was the source code.  I made one minor change and recompiled - I edited everywhere where I saw temperature in Centigrade and changed it to Fahrenheit.

rpiTemp

So the next step was to make it easy to get to.  I don't want to log in to my Raspberry Pi via SSH terminal just to check the temperature.  So I decided that it seems Node.JS is the way to go because I can very easily write a web server for it.

nodeTemp

Nice and simple.  And of course, the code:

-73-

UPDATE: I've had this running a few days, and realized that it seems Node.js does not like to update as fast as I would like.  In fact, it doesn't update until I restart the server... not sure what to do about that, but it drastically limits the usefulness of that tool as a solution in this situation.


Category: Raspberry Pi

About the Author

Andrew is the owner of this blog and enjoys computer programming, building things, and photography. He's a pretty busy guy, which explains why updates to this blog are so infrequent.

2 Responses to Raspberry Pi Temperature Monitor

  1. [...] Visit KE8P’s blog. One of the articles documents using a Raspberry Pi as a temperature monitor. [...]

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