GardenBot - How To, soil moisture, water valve, light sensor
How To

This section has various tutorials on the different components you might need to build a garden monitoring system. The entire how-to section is organized by modules -- each kind of sensor gets its own module.

The overall concept is that you will generally have a microcontroller (like Arduino) hooked up to sensors (like soil moisture) and actuators (like a water valve). If we think of the whole system as a robot, then our microcontroller is our brain. Because of the long distances in volved in automation of even a small garden, some of the modules (like the soil moisture sensor) are bound to be physically far away from the brain. Usually the least expensive option is simply to run wires from the brain probably located in or near your house out to the sensors located in your garden.

Throughout these tutorials I use the term local circuit. This refers to the circutry that is needed to create something like a good signal for the microcontroller. There is not currently a GardenBot board, nor any general circuit for the whole project. Simply experiement with each module and wire things up, you will eventually have a system -- even if it is a simple one.

The Modules

The Brain
Garden Station
Soil Moisture Sensor
Soil Temperature Sensor
Light Level
Water Valve
Control Panel
Computer Module

soil temperaturesoil moisturegarden stationlight sensorcontrol panelwater valvepower modulebrain modulecomputer module

Running wires to remote modules

To connect the various remote modules (like the control panel or the garden station) to the brain, you will need to run wires -- some very long wires.

Probably the cheapest option is to purchase a roll of 6-strand phone wire (see the parts page). A 100 ft roll should give you enough length to get from the brain module inside your house to the garden station out in your garden, and from the brain module out to the control panel. These wired connections are reliable and cheap. And with a few junction boxes (see parts page), it's easy to connect the remote modules with the brain's local circuit.

These long-distance connections would be a perfect place for wireless connections. GardenBot does not currently support that. Please read the note on "more advanced options" on the about page.

Expanding your GardenBot

GardenBot is designed to be extensible. This means that if you want to expand your system to include more sensors or additional water valves, you can simply add on more modules (while making the appropriate changes to the code).

Let's say you want to add another soil moisture sensor so you can compare the two. Well, the simple version is that you simply build another moisture sensor and also duplicate the local circuit in the brain module.

But there are a few other steps to actually implement it. The data that you see on the charts percolates up from the Arduino board. And it is really just a comma separated list of the different sensor readings. When you add your new sensor, you will also need to add a new item to this data stream. And so, there are three different places you will need to update how this gets handled.

First there is the brain module (the Arduino board). This is where the data originates. So here you will need to add the new sensor to the data set so that the new sensor appears at the end of the comma separated list.

Next, the data is handed off to the local-connection sub-module (computer module). This sub-module reads in the data, and then sends it to the visualization module as well as writing it out to a CSV file. So, you will need to make sure that the script both looks for and outputs the data for your new sensor. Note that this module also inserts a time-stamp as the first data row and then puts the data it got from the brain afterward.

Last, the data is delivered to the visualization sub-module (computer module). Here the data is converted and used to build the charts. This means that you will need to add your new sensor to this script so that it shows up in the chart.

So when you add or remove sensors, remember to change the way the data is handled in all three places so that the data stream is consistent.

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