I have spent several nights already trying to get two Arduino boards, each equipped with an Xbee-shield, to communicate. I worked on the example provided on the Arduino site, but no luck It turned out that I obtained two shields with “Series 2″ radio’s, which meant the example code would not work right off the bat. But, a post on Didier Stevens’ website pointed me in the right direction and eventually I was able to get both boards running and communicating.

The two boards seem to be communicating as one is sending the signal to switch an LED on and off every second on the other board. I see the LED switching on and off, but the behaviour is quite erratic. So, more investigation to be done there…

To be continued…

If you want to follow the prototype on twitter, follow @ProjectG3H

There are some issues with the temperature readings as they spike to impossible levels every now and then. I will have to get into that later. But, for now the prototype is able to get environment data and connect to the internet to tell the world about them. And it was not a very hard thing to do. Very exciting!

I will do a thorough write-up later to share as much info as possible, but for now I am just so excited that this is actually sort of working, that I had to share!

Below is a little preview of the sensor data that is sent to pachube!

Temperature (in Celcius):

Light (value from the LDR):

Soil moisture level:

The grid structure is based on the square foot gardening method, by Mel Bartholomew. Since I do not have a huge garden to grow vegetables, I heard about square foot gardening and decided to give that a try.

I bought this book to get to know a bit about it:

And with the box ready to go, it was time to plant the first seeds. Actually, I made two boxes: one in the open air, one for use as a small green house.

And so we ended up with two boxes filled with different kinds of vegetables and some fruit: brocolli, cauliflower, carrots, lettuce, rocket salad, onions, radish, beets, tomato’s, two different types of strawberry, red peppers and bell peppers. And for fun, we also put some seeds in a propagator: cucumber, melon, aubergine and some beans.

The G3H project electronics, will focus on the greenhouse first. The idea is to monitor conditions in the greenhouse, such as temperature, soil moisture levels, amount of light. And with the information, eventually control a watering system as well as opening and closing doors. A sensor unit in or on the greenhouse will wirelessly transit sensor readings to a receiver in the house which will publish data online. Services like twitter and pachube come to mind

I have ordered additional (arduino) hardware and started work on a prototype. Also, a sensor tube to use inside the greenhouse is in the making. More about that later

This is the bottom of the greenhouse box with weedcloth attached

The top half of the greenhouse is the glass part, which is not actually glass, but some sort of double sided transparent plastic. The whole frame is aluminium. As you have probably guessed: this was bought, not made by me

After finishing the box and reinforcements to the bottom, it was getting too dark to snap a decent photo, so that will have to wait for later. But I will finish this post with an image of the top half:

And in learning both fields more or less simultaneously, I came up with an idea after reading Make Magazine 18. In that issue, a project is described that uses an arduino to monitor plants and water them automatically, as well as switch on growlights when the plants did not get enough light during the day.

Combined with some stuff I read on square foot gardening and a good offer on a small greenhouse I came up with the idea to build a small, soft of, square foot garden, add a greenhouse on top and control the whole thing with an arduino.

My brother-in-law heard about it on twitter (I am @ArnoJansen, though part of my tweets are in dutch) and called in a “Willy Wortel” invention. Willy Wortel is dutch for Gyro Gearloose, hence the working title for this project: Gyro Gearhead GreenHouse, or G3H in short.

I am currently building the garden box and the greenhouse and have started on setting up a prototype board with the arduino to measure light, temperature and soil humidity. I did take some pictures which I will share later.

For now, let me show you the sensor testcode as I currently have it in my Arduino IDE (it assumes the same setup as the garduino article in Make Magazine, although you may want to change pin-outs):

// Project: G3H Sensor Testcode
// Author: Garduino project, Make Magazine 18 / Modified by Arno Jansen
// Version: 0.1
// Date: April 7, 2010

//include the datetime library, so our garduino can keep track of how long the lights are on
#include <DateTime.h>

//define analog inputs to which we have connected our sensors
int moistureSensor = 0;
int lightSensor = 1;
int tempSensor = 2;

//define digital outputs to which we have connecte our relays (water and light) and LED (temperature)
int waterPump = 7;
int lightSwitch = 8;
int tempLed = 2;

//define variables to store moisture, light, and temperature values
int moisture_val;
int light_val;
int temp_val;

//decide how many hours of light your plants should get daily
float hours_light_daily_desired = 14;

//calculate desired hours of light total and supplemental daily based on above values
float proportion_to_light = hours_light_daily_desired / 24;
float seconds_light = 0;
float proportion_lit;

//setup a variable to store seconds since arduino switched on
float start_time;
float seconds_elapsed;
float seconds_elapsed_total;
float seconds_for_this_cycle;

void setup() {
//open serial port
Serial.begin(9600);
//set the water, light, and temperature pins as outputs that are turned off
pinMode (waterPump, OUTPUT);
pinMode (lightSwitch, OUTPUT);
pinMode (tempLed, OUTPUT);
digitalWrite (waterPump, LOW);
digitalWrite (lightSwitch, LOW);
digitalWrite (tempLed, LOW);

//establish start time
start_time = DateTime.now();
seconds_elapsed_total = 0;

}
void loop() {
// read the value from the moisture-sensing probes, print it to screen, and wait a second
moisture_val = analogRead(moistureSensor);
Serial.print(”moisture sensor reads “);
Serial.println( moisture_val );
//delay(1000);
// read the value from the photosensor, print it to screen, and wait a second
light_val = analogRead(lightSensor);
Serial.print(”light sensor reads “);
Serial.println( light_val );
//delay(1000);
// read the value from the temperature sensor, print it to screen, and wait a second
temp_val = analogRead(tempSensor);
Serial.print(”temp sensor reads “);
Serial.println( temp_val );
//delay(1000);
Serial.print(”seconds total = “);
Serial.println( seconds_elapsed_total );
//delay(1000);
Serial.print(”seconds lit = “);
Serial.println( seconds_light);
//delay(1000);
Serial.print(”proportion desired = “);
Serial.println( proportion_to_light);
//delay(1000);
Serial.print(”proportion achieved = “);
Serial.println( proportion_lit);
Serial.println();
Serial.println();
Serial.println();
Serial.println();
Serial.println();
Serial.println();
Serial.println();
Serial.println();
delay(1000);
//turn water on when soil is dry, and delay until soil is wet
//if (moisture_val < 850)
//{
//digitalWrite(waterPump, HIGH);
//}

//while (moisture_val < 850)
//{
//delay(10000);
//}

//digitalWrite(waterPump, LOW);

//update time, and increment seconds_light if the lights are on
seconds_for_this_cycle = DateTime.now() – seconds_elapsed_total;
seconds_elapsed_total = DateTime.now() – start_time;
if (light_val > 900)
{
seconds_light = seconds_light + seconds_for_this_cycle;
}

//cloudy days that get sunny again: turn lights back off if light_val exceeds 900. this works b/c the supplemental lights aren’t as bright as the sun:)
//if (light_val > 900)
//{
//digitalWrite (lightSwitch, LOW);
//}

//turn off lights if proportion_lit>proportion_to_light, and then wait 5 minutes
//if (proportion_lit > proportion_to_light)
//{
//digitalWrite (lightSwitch, LOW);
//delay (300000);
//}

//figure out what proportion of time lights have been on
//proportion_lit = seconds_light/seconds_elapsed_total;

//turn lights on if light_val is less than 900 and plants have light for less than desired proportion of time, then wait 10 seconds
//if (light_val < 900 and proportion_lit < proportion_to_light)
//{
//digitalWrite(lightSwitch, HIGH);
//delay(10000);
//}

//turn on temp alarm light if temp_val is less than 850 (approximately 50 degrees Fahrenheit)
if (temp_val < 850)
{
digitalWrite(tempLed, HIGH);
}
}

/
Project: G3H Sensor Testcode

// Author: Garduino project, Make Magazine 18 / Modified by Arno Jansen

// Version: 0.1

// Date: April 7, 2010

//include the datetime library, so our garduino can keep track of how long the lights are on

#include <DateTime.h>

//define analog inputs to which we have connected our sensors

int moistureSensor = 0;

int lightSensor = 1;

int tempSensor = 2;

//define digital outputs to which we have connecte our relays (water and light) and LED (temperature)

int waterPump = 7;

int lightSwitch = 8;

int tempLed = 2;

//define variables to store moisture, light, and temperature values

int moisture_val;

int light_val;

int temp_val;

//decide how many hours of light your plants should get daily

float hours_light_daily_desired = 14;

//calculate desired hours of light total and supplemental daily based on above values

float proportion_to_light = hours_light_daily_desired / 24;

float seconds_light = 0;

float proportion_lit;

//setup a variable to store seconds since arduino switched on

float start_time;

float seconds_elapsed;

float seconds_elapsed_total;

float seconds_for_this_cycle;

void setup() {

//open serial port

Serial.begin(9600);

//set the water, light, and temperature pins as outputs that are turned off

pinMode (waterPump, OUTPUT);

pinMode (lightSwitch, OUTPUT);

pinMode (tempLed, OUTPUT);

digitalWrite (waterPump, LOW);

digitalWrite (lightSwitch, LOW);

digitalWrite (tempLed, LOW);

//establish start time

start_time = DateTime.now();

seconds_elapsed_total = 0;

}

void loop() {

// read the value from the moisture-sensing probes, print it to screen, and wait a second

moisture_val = analogRead(moistureSensor);

Serial.print(”moisture sensor reads “);

Serial.println( moisture_val );

//delay(1000);

// read the value from the photosensor, print it to screen, and wait a second

light_val = analogRead(lightSensor);

Serial.print(”light sensor reads “);

Serial.println( light_val );

//delay(1000);

// read the value from the temperature sensor, print it to screen, and wait a second

temp_val = analogRead(tempSensor);

Serial.print(”temp sensor reads “);

Serial.println( temp_val );

//delay(1000);

Serial.print(”seconds total = “);

Serial.println( seconds_elapsed_total );

//delay(1000);

Serial.print(”seconds lit = “);

Serial.println( seconds_light);

//delay(1000);

Serial.print(”proportion desired = “);

Serial.println( proportion_to_light);

//delay(1000);

Serial.print(”proportion achieved = “);

Serial.println( proportion_lit);

Serial.println();

Serial.println();

Serial.println();

Serial.println();

Serial.println();

Serial.println();

Serial.println();

Serial.println();

delay(1000);

//turn water on when soil is dry, and delay until soil is wet

//if (moisture_val < 850)

//{

//digitalWrite(waterPump, HIGH);

//}

//while (moisture_val < 850)

//{

//delay(10000);

//}

//digitalWrite(waterPump, LOW);

//update time, and increment seconds_light if the lights are on

seconds_for_this_cycle = DateTime.now() – seconds_elapsed_total;

seconds_elapsed_total = DateTime.now() – start_time;

if (light_val > 900)

{

seconds_light = seconds_light + seconds_for_this_cycle;

}

//cloudy days that get sunny again: turn lights back off if light_val exceeds 900. this works b/c the supplemental lights aren’t as bright as the sun:)

//if (light_val > 900)

//{

//digitalWrite (lightSwitch, LOW);

//}

//turn off lights if proportion_lit>proportion_to_light, and then wait 5 minutes

//if (proportion_lit > proportion_to_light)

//{

//digitalWrite (lightSwitch, LOW);

//delay (300000);

//}

//figure out what proportion of time lights have been on

//proportion_lit = seconds_light/seconds_elapsed_total;

//turn lights on if light_val is less than 900 and plants have light for less than desired proportion of time, then wait 10 seconds

//if (light_val < 900 and proportion_lit < proportion_to_light)

//{

//digitalWrite(lightSwitch, HIGH);

//delay(10000);

//}

//turn on temp alarm light if temp_val is less than 850 (approximately 50 degrees Fahrenheit)

if (temp_val < 850)

{

digitalWrite(tempLed, HIGH);

}

}

See here the progress after only 4 days:

That was on March 2, and look at the progress two days after that:

This looks very promising. Some of the earth is already being pushed out by the developing roots of the seeds, so I will have to put them in a larger pot this weekend. It is beautiful to see the seed-shells still hanging on one of the leaves. Beautiful to see these germinate and grow so fast! It is also evident, one of the six pots is not doing anything.

Unfortunately, the herb-kit and the lavender have not shown any progress yet

I got myself a few different kits to see how good they are (or probably, how good I am). I bought one with sunflowers, one with lavender and one kit with six different herbs; Parsley, Chives, Marjoran, Thym, Celery and Basil. They cost between 2,5 and 4 euro per kit. Besides these little greenhouses, I also bought a little bonsai tree kit.

The kits come in little plastic greenhouses:

When opening the kit, you will find six small pots, a description and a bag containing the earth. In this kit the pots were clay, which gives it a solid feel. The sunflower kit as well as the lavender kit contained plastic pots, which was a bit of a disappointment. Clay seems so much more cute.

The whole thing is pretty easy to put together. Put the earth in the pots, put the seeds in the earth, make sure the earth is moist and compact it a little bit, and put the pots back in the little greenhouse.

A tip for those that do not have green fingers normally (much like me): When you start a kit with six different herbs, you probably won’t know what herb is in which pot once you put it all together, so mark the pots

Once all is in the greenhouse, you just put it in a spot with natural light in your house and keep it at room temperature (around 20 degrees Celsius). Make sure you keep the soil moist, but do not drown the seeds.

Depending on the kit you bought, the instructions may be a bit different. These herbs are to be in a light spot. So do the sunflowers. But a little bonsai kit I bought (more on that in later posts), needs the shade.

In a bout 4 to 10 weeks, these should germinate and start showing us some life. When they have grown to be about 3 to 4 cm, they have to be put in separate, larger pots of about 10 cm diameter. The sunflowers I plan to put in one big pot, and probably the lavender too.

Once the sunflowers start growing, it will be important to turn around the greenhouse every day, to prevent the flowers from growing to the light on one side only.

First impressions are: fun! This is simple fun and feels a bit like having a pet. You will need to take good care of these in order for it to grow. However, the plastic greenhouses are flimsy and do not work very well. I am probably going to look for something nicer to grow them in.

But for now let’s see how this goes. I plan to show you photo’s here of the progress on a regular basis, but it will be a few weeks before anything will start to show.