I’ve been working on this for a while now but have finally managed to get hold of all the additional fancy parts I wanted. I have a prototype (excluding the ethernet shield) which reads from all sensors but I need to spend a little bit more time with the code that writes to the csv file on the SD-card before this can go into use.
The project:
I wanted to collect time stamped environmental data from the greenhouse in form of temperature, light intensity and humidity readings from several places. Initially I only wanted to use those to control fans and a heater but then decided to also open/close the window/louvre and collect the readout data onto a SD-card. I have a nice big IP67 enclosure installed in the greenhouse which has several cat6 cables coming in from the back which I currently use to supply power for the Arduino and hopefully at some point network access to check on the live conditions. Once the Greenhouse bit is done I’m hoping to add another measuring box outside to take the same reading plus wind and amount of rain as a little weather station. The greenhouse also has an irrigation system so my head already wants to buy more humidity sensors to go into pots and an array of motorised valves but that’s probably another separate system.
This is the current protoype which reads from a temt6000 ambient light sensor (http://www.sparkfun.com/products/8688), a HIH-4030 humidity sensor (http://www.sparkfun.com/products/9569) and a TMP102 digital temperature sensor (I2C). I’ve also played with a simple light sensor and s TMP36GZ which are still on the breadboard. The other bits involved are an Adafruit Data logging shield (http://www.adafruit.com/products/243), a ProtoScrewShield (http://wingshieldindustries.com/products/protoscrewshield-for-arduino/), an Arduino Uno and hopefully in the future one of the new Ethernetshields with SD-card slot (http://www.adafruit.com/products/201).
I have already started to build the first fan can (just a 330ml soft drink can with a set of sensors and a fan to suck air through the can) and successfully collected data onto the SD card from the basic light/temperature sensor setup which I then plotted with gnuplot (http://www.gnuplot.info/) which is pretty much the example provided by Adafruit (http://www.ladyada.net/make/logshield/use.html) which I found on my way looking for something to plot the csv.
The main effort is actually to get the sensors right. The I2C temperature sensors were a bit tricky as I had never worked with I2C before, the humidity sensor had to be tied to the temperature sensor readouts and the sample code for the data logging shield was not really meant to work with my sensors…