|A Previous Year's Tomatoes from our Garden|
Note: This is just a teaser. A full how-to will follow some time in the future.
As regular readers know, we here at Digital Diner have grown tomatoes and veggies every summer for years. Recently, we've been experimenting with hydroponics. It has been pretty amazing seeing how our hydroponics plants perform compared to our more traditional, geoponic garden. We are still learning, but the results are quite impressive with plants growing much faster, with no herbicides or pesticides and using only a fraction of the water of standard gardening. There are some complexities, like understanding how to manipulate the nutrients etc, but overall, we have been mightily impressed.
|The trusty old SunSPOT|
watching over the tomatoes
To start with, we like graphs. The graph below shows live feed from the sensors in our hydroponic garden. Right now we have only two sensors connected, but we can easily support several more. The blue line shows the water level in our ebb and flow hydroponic system. When it goes high it means that the pump has turned on and water is pumped into the system. When it drops down, it means water is draining out of the system. In this type of hydroponic system that cycle occurs regularly when things are working correctly. When the water level gets too low (due to evaporation) the pump wont turn on and we will see it here in the graph. Later we will implement some sort of alerts to tell us of this condition, but for now it's just a graph.
The black line shows moisture level in one of our aeroponic systems. It is using a soil moisture sensor, so it isn't exactly designed for measuring humidity, but it sort of works. Generally speaking, if that line goes to zero for too long, it means that the fogger is not doing its job and we need to take action. If all is going well, the graph is being updated every few seconds while you watch right now and you should see the blue line periodically bouncing up and down while the black line squiggles around somewhere above 0. If not, either we are working on the system right now, or we have a problem.
Note that you can scroll around, looking back over historical data, by moving the bar at the bottom. You can change the time scale by dragging the sides of the region at bottom or clicking one of the buttons along the top left to look at the last 5 minutes, 30 minutes, 6 hours, 1 day or week.
The technology involved in making this system is quite complex, but amazingly quite available to us common folks. The basic system architecture is shown in the diagram below:
|Moisture sensor inside an aeroponic system|
|ChipKit being installed on the ebb and flow system|
All the code is in a GitHub repository that we will publish here when we get a little further along on the project. For now, just let us gloat a little about the cool live graphs we got working this weekend.