Category Archives: processing and arduino

Millennium Bridge Thermal Interactive

‘A Day in the Life of the Millennium Bridge’ by Joseph Giacomin was a collaboration between myself, Joseph and Kaveh Shirdel as part of the new exhibition in Arup Phase 2 called Bridge Stories.

bridges on the move

They say:

“The works in this exhibition celebrate the last half century of bridge projects and the engineering that has made them possible. They also show how the use of film and photography has changed since the first decades of Ove Arup and Partners – founded in 1946.”

In this guest posting Joseph describes the story behind the thermal imaging.

Millennium Bridge Story

Cold blue and hot red: can thermal photography help the Millennium Bridge to reveal itself? Does enhanced perception tell us a different story from the obvious, the everyday, the one which we already know?

A thermal journey across the Millennium Bridge reveals a strange new perceptual stage in which the “things in themselves” occupy unexpected places and exhibit unexpected shapes and colours. Parts of the bridge, parts of the city and parts of the people suddenly appear strange and unexpected. The metal supports of the bridge cool in the wind while the solid masonry foundations stubbornly retain their heat. People appear as bright glowing light bulbs, centres of heat, moving over and around the bridge in their living, unmechanical, way. Interaction occurs, with people imprinting their life force on the bridge through heat transfer from direct contact. The dome of St. Paul’s cathedral glows red as its lead covering heats in the afternoon sunlight. London’s masonry and glass glow.

To thermal eyes the Millennium Bridge reveals a new version of its story. This exhibition provides many views, and thus many stories, which are told through thermal photography. Often seen as technical tools, thermal imaging cameras can also act as translators between ourselves and our physical world, expressing sensations which cannot be stated in words, and capturing photographic insights which are lost in the visual spectrum due to clutter, confusion and overwhelming detail.

Thermal photography helps to reveal a secret life of Millennium Bridge, that of heat and energy. The choreography of sun, wind, materials, physics and living creatures is revealed to thermal eyes, and the many secret stories of everyday bridge life are told from a different perspective and a different point of view. Stability and motion, man and nature, routines of everyday life, all these plots and more are acted on the thermal stage which is Millennium Bridge.

Guide to the Thermal Images

The thermal images of this exhibition all 320X240 pixel JPEG images shot using a 60 Hz thermal imaging camera which was similar in appearance to a camcorder. Since such cameras measure a property, temperature, which is not part of the visible light spectrum, pseudo-colour was used to indicate the variations in temperature. The pseudo-colour scheme adopted was bright red-orange for the hottest temperature found in the individual image while dark blue was used for the coolest. Since the pseudo-colour scheme was normalised for each image individually, the same colour can indicate different temperatures when appearing in different images. For the current exhibition, therefore, colour should be considered to provide a measure of relative temperature rather than of absolute temperature.

Thermal imaging, or, more precisely, infrared thermography, consists of measuring the infrared radiation of the electromagnetic spectrum from approximately 900 to 14,000 nanometres of wavelength. Infrared radiation is one region of the electromagnetic spectrum, other regions being for example those of the gamma rays, x-rays, ultra violet light, visible light and radio waves. Infrared radiation is emitted by all objects and the amount of emitted radiation increases with increases in the temperature of the object. The temperatures which can be measured by means of a modern thermal imaging camera are normally from approximately -50 °C to 2,000 °C.

Infrared radiation is measured using a thermal camera in much the same way that visible light is measured using a digital camera. However, while digital cameras use a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS) sensor, thermal imaging is based on the use of focal plane array (FPA) sensors which respond to the longer wavelengths of the infrared region of the electromagnetic radiation. Given the complexity of the FPA sensors, the maximum resolution which can currently be achieved is lower than that of CCD or CMOS sensors. Most thermal imagining cameras have the relatively low resolutions of 160×120 pixels or 320×240 pixels, with the most expensive current models reaching 640×512 pixels.

While the amount of thermal radiation depends greatly on the surface temperature of the object which is being measured, the surface temperature is not the only factor involved. Other factors which effect the measurement include the emissivity of the object which is being captured, the amount of radiation arriving from the surrounding environment and the atmospheric absorption between the radiating object and the thermal imaging camera. Emissivity and atmospheric absorption thus affect the measured temperatures, and if not carefully compensated at the time of each measurement can lower the accuracy of the temperature values.

Of the factors effecting the accuracy of thermal images, the biggest is the emissivity, meaning the ability of the object’s material to emit thermal radiation. Every material has an emissivity value which is in the range from 0.0 (no ability to emit thermal energy) to 1.0 (complete emission of all thermal energy). In addition, the emissivity value is not a fixed value for most materials, but is actually a continuous function of the temperature. Given the complex physics, the maximum theoretical measurement accuracy of a thermal camera is achieved only when the emissivity value of the object which is being studied is known or when the camera can be calibrated on-sight against a known reference source of thermal radiation. In the case of the images found in this exhibition, the camera was set to run using a stored internal emissivity table, thus the camera was not calibrated for each shot so as to achieve the maximum possible accuracy.

Joseph Giacomin, Oct 2010

[If you like these images, you may also be interested in his new book "Seeing the World Through 21st Century Eyes"]

An online gallery of the photos is available and once the installation is complete more photos will be uploaded to the gallery.

And finally, it’s almost 10 years old, but still fascinating to watch, a video shot during testing of the Millennium Bridge where the footfall of 2000 members of the public was being monitored against the Synchronous Lateral Excitation of the bridge.

Millennium Bridge from Duncan Wilson on Vimeo.

And one from the local news on the opening day…

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Hackday fun


I spent the weekend at the Yahoo Hackday last week. As Crave puts it

“The idea behind it was simple: you’ve got exactly 24 hours to hack together the most interesting, innovative, useful or fun piece of software or hardware, using developer tools from Yahoo, or anyone else for that matter. ”

David Filo opened the event, I learnt alot about the Yahoo API’s available – a great way for them to show me what i could be using… and thought the talk by Rasmus Lerdorf on hacking with PHP was great.

Next steps – how to organise a hackday at Arup for the virtual design, BIM, GIS and intranet communities…

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Interactive Lighting Workshop

A second interactive lighting workshop is being held at Arup, organised by Tinker with presentations from Arup, UVA and Philips Lighting.

The workshop will cover an intro to DMX control using Arduino, examples and stories from light installations by Arup, UVA and Tinker, insight into emerging technologies and products from Philips and access to DMX controllable installations (Forcefield, and Optimise) so that you can test your learning on real installations.

If you are interested in hacking DMX controlled lights with Arduino or just want to learn about how interactive light installations work then why not join us… the project page is on the Tinker site

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Forcefield Interactive

On Christmas Eve Forcefield Interactive went live with the addition of two sensor inputs to allow visitors to the exhibition to play with the light installation.

A kiosk inside the space as well as facing the outside of the window on Fitzroy Street allowed visitors to put their Oyster card on a reader and have their card trigger a unique color to travel throughout the light sculpture. Additionally, a color sensor inside the space allows visitors to place an object of color on a reader, select the color and send it traveling through the installation. The default light display is generated using Perlin noise with the 192 lights being controlled by a single Arduino.

Other collaborators included and Artificial Tourism

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H3 Interactive Lighting workshop

We have been working with here in London in organising a few workshops around Arduino. The first is on Interactive Lighting and will involve a mix of presentations on current state of the art and building some simple protoypes. Guest talks include our own Francesco Anselmo, Massimo Banzi from and Daniel Hirschmann from Jason Bruges Studio. The giveaway swag to all attendees include a DMX controller and a DMX shield for Arduino.

For more info and to book a space jump to the workshop web page. This workshop is at Arup in London on Sat/Sun 10/11th May.

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H3 RFID workshop at Arup

I’m wishing that I could attend all of this workshop but the best i can do is a bit at the start and the end…. H3: RFID is the second of a series of hardware hacking workshops in London organised by Massimo Banzi (Arduino founder facilitates the event with Matt Biddulph ( The event will be held at the Arup offices and is ideal for anyone wanting to explore RFID and Arduino. The entry fee even includes an RFID kit to take away to show off your prototype. For more info visit the event page. Hopefully the first of many.

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Arduino BT PIR sensor

Finally got the Arduino BT PIR working and installed in Central Saint Martins and pushing data to the data server. Some photos are on Flickr and more will follow. The Arduino code used is here and a processing app to view the data being sent over the BT serial here. I ended up using a Perl script on the live installation. I will post that once I extract it from the installation.

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traer.physics – processing

Would be nice to use this processing library to represent temperature in an environment – *how fast the fire is burning*.

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accelerometer memsic 2125

Have had a frustrating day with this accelerometer – cannot figure out the code calculating the actual acceleration in Arduino – see forum posting.

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Fluidforms – punch bag design

A great example of how people are using Arduino as an input conduit to design product…. uses a home made pressure sensor (conductive wire grids separated by foam) around a punch bag as the input device, the ouptut is a 3D model of the object to be made. Great video, love the soundtrack.

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