We will create and field test a farmer-built electronic tool that can monitor greenhouse temperature, record greenhouse data, and alert the farmer to problems in the greenhouse via cell phone text message. This tool will be much more affordable and useful than commercially available greenhouse alarms (which rely on landline connections or internet connections, which usually aren’t available in the greenhouse). The tool will be created through a partnership between a farm and two consultants with expertise in electronics development and software programming. Once developed, the tool will be field tested by several farmers, to ensure that it is accessible and appropriate for various operations. Once we’ve got it right, we will do outreach to ensure that many other farmers can benefit from this useful and economical tool. The project will also leave open possibilities for future developments: while this tool will be simple, straightforward and approachable for farmers, it will also be flexible and robust enough that more technically inclined farmers could add features to it for greater functionality, such as turning on or off greenhouse fans, monitoring soil moisture and humidity, or monitoring produce storage facilities.
Bill of Materials:
|10K Precision Epoxy Thermistor||$4|
|SD Card 1GB or more||$5|
|9V Power Supply||$6|
|Motorola C168i + SIM Card||$30|
|Backup 9V Adapter||$6|
|2 DC barrel jacks||$2|
Download Arduino IDE v1.0. An IDE is an "Integrated Development Environment," or in plain english, it has everything you need to program your Arduino. The full tutorial is available on the Arduino site but I will fill in a few concepts as we go.
In this Arduino environment, you will be writing code in C++. There is an upload button which automatically "compiles" your code (turns it into processor code) and then uploads it to your Arduino. If you are working on your code for a while, it is helpful to compile it periodically to catch syntax errors as you make them. If all this is overwhelming, don't worry. You don't need to write any code for this project and all you have to do is learn how to upload code!
Your IDE also keeps all your "libraries" in order. Libraries are pieces of already written code that you can call on when writing your Arduino program. They are usually device specific, so for example, with Fido we use a library that was specially written for a cell phone and another for the data logging shield.
Download the libraries and unzip them. There should be three individual folders, each containing at least two files, one with a .h suffix and one with a .cpp suffix. Open your Arduino sketchbook folder. If there is already a folder there called libraries, place the library folders in there. If not, create a folder called libraries in the sketchbook folder, and drop the library folders in there. Then re-start the Arduino programming environment, and you should see your new library in the Sketch > Import Library menu. Additionally, under File > Examples, you should now see our libraries along with their example sketches.
Finally, before your IDE will be able to see your Arduino, make sure your computer recognizes it! There are device drivers included in the Arduino folder and if you have trouble, refer to the Arduino web site.
If you just read all this and need a more detailed tutorial, check out this one from Lady Ada. It will be less specific but if you are serious about learning how to use your Arduino to its full potential, their learning system will bring you up to speed VERY quickly and efficiently.
Activate SIM card and load with text messages
We are using the Motorola C168i because of the 3/32 stereo jack connection - it's really easy to make the Arduino interface with it but sadly more recent cell phones don't use that kind of connection anymore.
You will need a SIM card for your C168i if you don't yet have one. Unless you specifically sought out an unlocked one, your phone will most likely be locked to the AT&T network and you will need one of their SIM cards which can be purchased on their site. You may also be able to find one in their stores (to be confirmed) and you can definitely find them at Radioshack (just buy their cheapest Go Phone and it will be included). When activating it, I recommend the 10c/min plan, and that you simply buy text message packages that are valid for 30 days ($5 for 200, $10 for 1000).
Also, since we will be leaving our cell phone charging most of the time, you'll benefit from going into the settings and silencing the phone so as not to get beeped at every few minutes.
Assemble Adafruit data logging shield following their easy tutorial
1. If you don't have a vise, laying the board down on some bricks or anything other similar setup should do the trick
2. You do not need to solder the RTC clock mount if you don't want to
3. You should wire a jumper between pins 3 and 4 and the LED holes right next to them if you want them to blink (I recommend clippings from the legs of a diode to do so)
Make the wire to connect your cell phone to your Arduino
Build your back-up battery
Upload the Fido sketch from File > Examples > Fido to the shield and program via text message