mini vacations board

yesterday martin hug just send us this


it’s our new mini vacations board V3. the mini is meant to control the UFRRJ watering system, collect/store data and has an optional wireless data socket to upload data or change configurations.

contents: ATMEGA328, EEPROM serial 256K, usb port, FTDI, wifly, 3V rele, Li-Ion battery.

we’ll are making 10 of them and we need 10 developers that are willing to take one and start debugging :) we will realease them free you just have to tell us why you want it and figure out a transportation solution from barcelona to you :p




next stop paris :)


here we go again :) the next 3 weeks I’ll be in paris with andreu, andreas, shu lea (greenrush), samuel and fransini working on the project la graine et le compost.

we will try to build together software and hardware tools that can we bring local seeds to urban farmers and promoting compost and social exchange. as usual, if you are in paris pay us a visit and we will find a way for you to contribute. leave here some screenshots of the software development until now.





About temperature sensors

I’ve been experimenting with and reading up on the LM35 temperature sensor, used by the On Vacations board. The output pin of the sensor connects directly to an analog input on the Arduino, and after reading the value of the pin, the temperature (in Celcius) is calculated with this formula:

temperature = 5 * (analog value from sensor) * 100 / 1024

However, I found that the temperature values fluctuated by 1 or 2 degrees for every reading (taken once a second).  To stabilize the readings, I tried to average the readings in various ways, such as by taking several successive readings and then averaging the values, or by keeping an average of the last 10 readings (over the last 10 seconds).  The results were quite similar in each case, the temperature reading was notably more stable, but when it did fluctuate, it was still by a degree or two.

In reading about taking better readings from these sensors, I came across lots of info about some general downfalls with Arduino’s analog readings.  There are two particularly relevant posts on the Adafruit forum here and here, regarding multiple analog readings from different pins.  The solution seems to be the inclusion of a short delay (10ms) after each reading.

Adafruit also has a nice tutorial on temperature measurement, and it sounds like the LM36 might be a better choice for use with the On Vactions boards — depending where a farm/garden is located — since it can measure sub-zero temperatures without a negative power supply.

I also came across a library directed to improving Arduino’s analog functions.  I’m looking forward to experimenting with this.

Web development process

The first thing I started to do when i joined the group was to improve the blog both visually and functionally. (because we all know that the default kubrick theme is really ugly and the web usability is in the minimum level!:))
So i started out with some sketches and tried to create an identity with the logo, background and some other elements of the blog. After long discussions and brainstorming with Hernani, we wanted to keep it really simple and clear for everyone but also emphasize the sustainability and urban farming perspective of the project visually.

Here are some first sketches.

And this is the last version of how we decided to develop the blog.

“What to seed” app

After designing the seed boxes and connecting with seed banks that can help us to provide the seeds (by the way we managed to get thumbs up from Hudson Valley Seed library to be our provider soon), i went ahead and started to put some information together in a processing application that will help users to decide what to seed, how to seed and where and when to seed extra. At this point, the climate zones were very essential criteria for seeding and Maria from Barcelona group helped us out to shape the climate information to put in the application.

Here are some shots of the processing app.

Since refarm is expanding in Europe and the States, I added the language options in the interface. In addition Hernani and I did some brainstorming about what information would be needed and what criterias and variables would be added to the interface. The dimensions of the farm, the location of the farm, soil types options and etc.. were the first variables we thought that would affect the whole seeding process.

Another great feature of this one was also demonstrating “the friends and enemies” of that specific seed that the user decide to grow in his/her farm. So I added two submissions on the interface, one surrounding the main seed with friend seeds that can be added to the farm and can cultivate the farm with its nutrients and stuff and the other one surrounding this circle with enemy seeds that shouldnt be added to the farm.

However at the end we decided to combine this application with “the big brother” application that manipulates all the farming process.

The LEDs are on the wall

Greetings!  I’m happy to make my introduction here on the Re:Farm blog.  My name is Andrew O’Malley and I’m a Canadian artist/engineer.  My main artistic interests are animated lighting installations and fixtures, and electronic music production and DJ’ing.

[ Eyebeam bio ]

These interests have brought me to NYC for the summer of 2010, where I’ve connected with Hernani’s Re:Farm project through his residency at Eyebeam.

My first objective is to create the PCB (circuit board) for the Re:Farm On The Wall module, a data visualization module using an LED display to present data away from the computer screen.

Here’s Hernani’s original sketch for displaying the soil moisture level from 6 sensors:

This design uses 7 LEDs to display the soil moisture level for each of 6 sensors (42 in all).  The design concept has been formalized as seen below:

The module still has 7 LEDs for each sensor (or farm/garden), but with the addition of LEDs between the groups (for a total of 48) to create a complete circle which can be used with other templates, such as the one below, for visualizing other data such as temperature or humidity:

Ideally, the board will also incorporate a stepper motor to drive a needle (like a speedometer) for an additional data channel.

I’m going to first concentrate on the LED display.  Since the board will make use of an ATMEGA microcontroller (Arduino) chip and an XBee radio (to receive the data), real estate on the approx. 3″ x 3″ board is already a bit tight, so I am currently researching Charlieplexing, an LED driving scheme which allows N*(N-1) LEDs to be directly driven by N pins of the microcontroller.  8 data pins from the microcontroller  can thus be used to control the 48 LEDs since Charlieplexing with 8 pins allows control of up to 8*7=56 LEDs.

At The Next HOPE conference this past weekend, Jimmie P. Rogers was demo’ing and selling his LoL (Lots of LEDs) Shields for the Arduino.  He has a great post about his work with Charlieplexing which I’m currently consulting.  Talk about serendipity!

In a way, the overlap between the needs of Hernani’s project and my own interests in lighting and internet-enabled lighting fixtures is serendipitous as well.

More soon!

27ºC in the compost – data visualization

wormonster- temperature visualizerone thing that was boring me a lot was the fact that I was spending too much time in front of the computer instead of being on the farm :) so I’ve built a low-budget-way to visualize the data without having to look at the computer screen. the above picture is from the “wormonster” that I made to monitor the temperature of my combox (a prototype from thanks petz;)


the idea is that you make one object and have multiple data visualization. this “wormchicken” is easy to make: you print the chicken, glue it on a cardborad, print what kind of data you want to visualize, add some recycled electronics, one arduino, upload new code, connect the sensors and voilá :)

as soon as I have the code ready (programmers needed:) and the diagram of the electronics I’ll post the DIY instructions.

monitor prototype


here is a prototype. and has the word say or maybe I should say.. everything is glued to make this picture :) but we went even further and we made a video of the prototype :p it readers the 6 humidity probes of different pots on the refarm 000. here is the frankensteincode that I glued from various sources.. a word for tom igoe and all the ITP-people-knowledge-data-base;)

please fell free to contribute

code for arduino

code for processing

diagrams, and ingredientes here on flirck.

video here

refarm scarecrow 6 humidity sensors from refarm the city on Vimeo.

refarm hydroponic


we have added some pics to our flickr account. some of them are the refarm hydroponic that we have built in interactivos09. here is the code that lalo (Eduardo Meléndez) prepared to us. enjoy and let us know what bugs did you find ;)

////////////////////////upload this code to arduino////////////////////////

int analog = 0;
int ledPin = 10;              // LED connected to digital pin 13

void setup()                    // run once, when the sketch starts
pinMode(ledPin, OUTPUT);      // sets the digital pin as output
pinMode(3, INPUT);

void loop()                     // run over and over again
analog = analogRead(5);

if(analog < 7){

analogWrite(ledPin, 125);   // sets the LED on
delay(30000);                  // waits 3 seconds
analogWrite(ledPin, 0);    // sets the LED off
delay(10000);                  // waits for a second


analogWrite(ledPin, 0);

delay(3600000);} // waits one hour


what should I plant?


now that I see a light at the end of the tunnel concerning the watering system I should start to think about what to plant. one plant doesn’t make one ecosystem and appears that everything in nature is connected. here is a visualization of some associations that could be used on a urban farm. I soon will explore more on this subject.