A very nice overview of the goals of the project were featured in the May 2011 issue. The interview was last year, but I didn’t get wind of the publishing until just a few weeks ago!

Thanks to Wired, and look out for a lot of updates on the Android app front! Progress is being made…

Wired article: http://www.wired.co.uk/magazine/archive/2011/05/start/breathing-in-the-data

For more community-based sharing, Citizen Sensor is now on GitHub and Upverter.

Here’s the GitHub repo (organization of the folder structure is still being worked on) : http://github.com/jmsaavedra/Citizen-Sensor

Upverter is a great new online tool for open source hardware. You can create schematics and it will automatically build a parts list and allow others to fork and edit the circuit design itself. It’s GitHub for hardware – and can even associate a git repo with your design. After creating an account and laying out the most recent Weather Tunnel design, Upverter featured it as the ‘design of the week‘! Awesome.

Another cool thing: I can embed schematics right on this page! Check out the Weather Tunnel unit design. It’s missing the Ethernet Shield for the Arduino – but all connections are to the Mega.

Click around:

I’ll be giving a talk about the DIY, open-source, educational application and aspects of environmental and air quality monitoring. I’ll also have a kiosk where I’ll have a few prototypes and some interactive live data feeds.

I’m also really excited to be installing a unit in Abu Dhabi! It’ll be posting live data to the Weather Tunnel Pachube account, as it will contain all the same sensors and use the basic design as the unit mounted at the Univ. of S. Wales in Perth Australia, that was installed several months ago for the Weather Tunnel project. You can find all datastreams, still live, here: http://pachube.com/feeds/22587.

The unit I will take to Abu Dhabi, will be the same as the Weather Tunnel design. Here’s a PDF about how that unit works:

I’m currently looking for someone to host a unit in Abu Dhabi! It only requires power and an Ethernet internet connection! Also a window nearby is helpful

The core concept of Weather Tunnel is to experience global environmental and weather data in real-time through interactive physical art installations. We have a really exciting list of partners working with us including Art Center Nabi in Japan, University of New South Wales in Australia, Universität der Künste Berlin in Germany, and several others. Each partner will be exhibiting their own interactive piece using real-time weather data, AND are hosting their own sensor node. I developed an installation called the E.S.Orchestra – A kinetic, autonomous instrument performing generative music based on real-time weather and environmental data, with my colleague Benjamin Bacon.

The sensors used in Weather Tunnel are directly related to my development of Citizen Sensor. However, there is one main difference: Weather Tunnel nodes are stationary. In order to achieve this, I opted to use the Arduino Ethernet Shield as the connection to the internet (as opposed to a cellular telephone data connection).

You can read all about the sensor units developed for weather tunnel on the WT Developer blog located here: http://tasml.parsons.edu/weathertunnel/sensor-information/

I’ll embed the main sensor document so you can check out what this unit looks like and how it works. You’ll notice I also included an LCD screen for debugging purposes. This was extremely helpful as we fabricated the units here in NYC and then sent them out to the partners around the world — there was a lot of debugging needed.

The other big difference is that these units are using Pachube to record and host our data. It’s been a great experience with Pachube, writing openFrameworks and Processing applications to connect and retrieve data in real-time using their very robust and well documented API.

You can look at all of the Weather Tunnel datastreams on Pachube here:
http://pachube.com/feeds?user=weathertunnel. Our user page is here.

I’ll be travelling to Beijing next week and will be there until the opening of TransLife on July 26. Very exciting!

Check out the interview here:

http://opensourcehardwarejunkies.com/2011/05/how-to-change-the-world-with-a-sensor-one-citizen-at-a-time/

Several of my prototypes were featured in an exhibition at the same Museum which ran for the month of October. A true honor, I hope to visit my new friends at the Köln International School for Design (KISD) again soon!  Thank you: Andreas, Sebastian, Ines, Marijke, Pia, and of course Prof. Erlhoff, and Gol! See you again soon.

Myself and the Köln Germany Design Preis Winner featured in a German Newspaper

All Design Preis Winner, 2010 -- congratulations

You can download the library here, obviously released to the public domain under creative commons.  To install, unzip the folder to the libraries folder of Arduino and open up the included example. You’re ready to go!

To order a Citizen Sensor MQ-7 Carbon Monoxide Sensor breakout kit from me, please email me. They are $15 + shipping (includes everything except an Arduino, and is compatible with any microcontroller with an ADC).

More info about the kit is available in the Make/Resources section of this site.

However none of them use it CORRECTLY.

I wrote about how the sensor is supposed to work in a previous post about the prototype of this kit.

I’ll be selling this (price to be determined) at Maker Faire NYC this Saturday and Sunday September 25 and 26.

I will also be giving a talk/demo of the system at the Make Magazine Stage on Saturday at 3:30pm! Very excited about sharing my work there.

Limor Fried (aka Lady Ada) is one hardware and software developer who has been working with Arduino, and has been a personal inspiration of mine for the last couple years. She has been prolific in terms of her development, documentation, and business savvy, particularly . Adafruit Industries (her + Phil Torrone) was pretty much unheard of 2 years ago, and is now in the forefront of DIY open-source hardware kits and projects. They share everything, and for someone working in this field has been an invaluable resource, from their forums to their weekly webcast, ask an engineer.

When I first discovered Adafruit’s BoArduino (an Arduino-compatible kit, designed to fit directly into a breadboard), I was instantly inspired. She tore the Arduino board down to it’s most basic parts, made them all through hole components, and cheap as hell (well, 40% than buying a blue board!). I of course prefer the DC BoArduino, as it is cheaper, smaller, and requires the cred-securing FTDI -> USB cable to program.

Being an open-source business, mean all files are available for hackery. As my project follows suit in this way (not everything is posted, but it will be!), I saw a really great potential to modify her design to fit a couple specifications I need.

1. The smallest possible footprint for the microntroller — this allows the user to have the most freedom in terms of embedding or enclosing their Sensor.
2. Bluetooth modem support ON BOARD. Meaning, I don’t want them to have to jerry-rig a solution to attach a BlueSMiRF or any BT modem to their unit.
3. Cost. There is no reason for the average Citizen Sensor user to reprogram their kit. It will come programmed, and configuration as to what sensors are attached to what pins can be done in the Android app. The DC BoArduino design saves money and space by eliminating the FTDI chip altogether. People who want to reprogram are probably ones who already own the FTDI -> USB cable already. Win-Win.
4. The ability to move forward with the design. Version 02 of the BoArduinoBT will cost about half the price – the surface mount bluetooth modem (RN-41, for example) costs about $25, as opposed to the breakout board(aka BlueSMiRF) which Sparkfun has marked up to a whopping $65 (a bit unreasonable, IMHO). I will be researching ways to attach this surface mount piece myself, and sell the board with that already installed. The SMT pieces on the BlueSMiRF are all available through-hole, and this will be were the majority of the design work will be needed – making this DIY.

I’m really excited to have been able to use Lady Ada’s design, and hopefully I will make it much more mine than just simply adding the BlueSMiRF footprint on the board.

OPEN-SOURCE FTW.  Go ahead and download yourself the BoarduinoBT v01 EAGLE schematic and board files to keep this beautiful cycle going.  Hopefully BoarduinoBT v02 (w/ SMT BT modem onboard) will happen before November.

MQ-7s are available from the manufacturer in either a metal enclosure

...or these orange plastic enclosures

These sensors, made by Hanwei in China, are super popular online – Sparkfun carries them, as does Polulu and several others.  They retail for about $5 by themselves, and a breakout can cost up to $10.  The MQ gas sensor series are great – they generally require 5v input and output an analog voltage – making them super easy to use.  There are models that measure Methane (MQ-4), Liquefied Petroleum Gas (MQ-5), and even Alcohol (MQ-3) among several others.

However, the Carbon Monoxide model (MQ-7) is unique in that it does not simply require a 5v heater voltage.  Reading the datasheet, you’ll see it requires a power cycle: 1.4v at 90s, and 5v at 60s and repeat.  From the datasheet:

There are a lot of ways to go about accomplishing this.  However, the datasheet makes no mention of current – just voltage. After a lot of testing, it became apparent that this guy needs quite a bit of current to take readings at all.  This is because of the nature of the sensor. Inside, a small filament is stretched between all pins.  This filament is coated in a chemical that is sensitive to a particular gas, in this case CO. When it is exposed to the target gas, the resistance of the filament itself changes, and so does the output voltage (Signal).

I made two different boards to accomplish this in the easiest way possible.  In one version, an adjustable voltage regulator is used to get a 1.4v power line.  A really tiny relay toggles between that voltage and the 5v from the Arduino circuit. The other version uses 4 diodes, in series, to drop the voltage down (it went about 1.2v each time). These are 4148 300mv diodes.  In both boards, a single digital pin can be used to toggle between the voltages – just send the pin LOW, and you get 1.4v, send it HIGH, and 5v is pumped to the sensor.  I will be releasing timer-based sketches with the board so that you can be doing whatever you’d like in the sketch, and don’t need to worry about the toggling – it will happen in the background. Check out the completed boards — these are barebones PCB prototypes.

Both versions on one board - the top board uses the linear voltage regulator, on the bottom are diodes in series to achieve 1.4v

<3 PCBs. Made in collaboration with Joel Murphy.

You can download these prototype schematic and EAGLE PCB board files here.