Battery Adapter for Canon Powershot SX200

Last year I bought a Canon PowerShot SX200 on ebay. I wanted to play a bit with CHDK, the Canon Hack Development Kit to make some timelapse things. Problem was, the battery would hold only up for 2 hours or so. Even worse, the camera has no power jack to attach a power supply. The solution is to buy a battery dummy that has a jack on its back. That costs like 30 euros!

3D printing to the rescue!

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The Indestructible Billboard

[vimeo 39831585 w=700 h=393]

In March Marcus of Interactive Matter and I helped Publicis to build an interactive billboard for Evoc.

Evoc makes backpacks with protectors, called LITESHIELD. The protector is used to absorb a good portion of an impact in case of an accident. So we were asked to build a billboard with an included backpack and a sensor, that measures an impact. The impact and the absorbed portion would be displayed on a screen, also integrated into the billboard. A webcam should take a picture of a candidate, while he tries to hit the backpack as hard as he could. The picture would then be uploaded to Facebook, if the candidate agrees.

Our part was all the electronics and programming. Rest of the innards was made by the great guys of Create and More. As sensor we used an Arduino and a accelerometer with +/-250g range. Whenever a punch is detected, the maximum value gets sent to an Processing sketch, that takes a picture, updates the display and sends the picture to Facebook. No open source here, it’s simply too ugly and we are embarrassed.

Presentation took place in Berlin at the end of March. Everything worked out really well. Only problem was a slightly flaky internet uplink. Next time we will have at least two 3G USB sticks as fallback. Despite that everyone had a lot of fun, especially the kids and some young guys, giving the billboard and the backpack a hard time. But it withstood. Of course.

The 2 Euros Machine

In January Kolle Rebbe, a german agency, asked if I could help them with their project. The idea was to have an interactive ad poster to collect money for Misereor, a german relief organization. The campaign is named “Mit 2€ viel bewegen”, which means something like “getting things moving with 2€”. You would donate a 2 Euro coin and the coin would travel through the poster, a bit like a marble in a marble machine. On the way to the bottom, the coin would trigger all kind of animations to show, what the money would be used for. Very cool idea!

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Audi Fan Messenger

Testing the Audi Fan Messenger

Almost a year ago Martin came to me and asked me, if would like to join him on a cool project. His idea was to put a LED POV into a real race car. Of course I wanted!


Every race event attracts a lot of fans. Martin’s idea was to integrate the fans into the race. The race cars should carry fan messages around the track and print them into the night.
The technique used for that is called POV (Persistence of vision). It is somehow related to Light Painting. For that you take a long exposure picture and move the LEDs through it. If the LEDs are switched on and off in the right pattern, it prints a readable message on the picture.

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Soldering is Easy

Soldering is easy. It realy is. If you are still in doubt, head over to, where you can find a really nice comic on how to solder, done by my good friends Jeff Keyzer and Mitch Altman.

Best of all, it’s totally open source!


Xeyes in Processing

Do you remember, when you first started your X and stared at Xeyes? Aaaah, those were the days.

I wanted to have Xeyes in Processing to have it as an example of some lines of code that could be easily integrated into an interactive demo or the like. So I thought, ok, that’s quite easy, just draw a bunch or ellipses and circles. Turns out that it is not that easy.

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TweetsOfWaste in Weave

A couple of months ago Martin came up with the idea to build a dustbin, that would take pictures of people using it and then send them to Twitter. We tried some different approaches and finally used an Arduino, a WiFly-shield and a c328 serial camera to build it. It worked really well and was a lot of fun.
What you see there on my desk is the current issue (2011/01) of Weave. Weave is a magazine that covers interactive design and such. We were asked to write an article on “internet of things” and now, there it is. It’s a tutorial on how to use Arduino with twitter and how to take pictures and upload them.

Here is a teaser of the article (in german).

I hope to find some time soon to document the project in a separate post. We’ll see. You can follow @TweetsOfWaste to see any updates of the project and the first couple of pictures.

Palo Altonale Workshop

End of October, Marcus and I gave a two day workshop on sensors, Internet of Things and Arduino. It was for people who had small to no knowledge about electronics and programming, so not for the average geek. The aim was to show how easy it is to build things that interact with the physical world. It was hosted at the Good School.

First day was training. With small examples on sensors and outputs we saw how easy it is, to collect real world data and act upon them. After that we connected the Arduino with a WiFly-Shield to the interwebs. At the end of the day all had an Arduino running, that did a search on twitter and if someone tweeted your name, an LED light up. Not bad for the first day.

Second day was free tinkering. Everyone could come up with ideas for projects. We gave some guidance of would could be achieved until the end of the day and what not. Then all started on developing their projects. Marcus and I had a lot to do in answering questions and giving hints into the right direction. At the end their was a presentation where all proudly presented their project. And they were really great. All teams came up with something that really worked, none failed. What a success.

That was a fantastic experience, having so many people together, tinkering and having fun. All of them were really engaged and fully committed to their projects. I took a couple of pictures, and guess what, all people you see on these pictures are smiling and enjoying what they are doing.

Pictures at Flickr.


Last weekend, Marcus of interactive-matter and I, gave a small introduction into internet of things and ambient devices at the Good School. The idea was to have two devices that show the current volume of two terms on twitter, e.g. love against hate. The demo should show how easy it is to connect the physical world to the internets. Marcus did the software part, so if you are interested in that, visit interactive-matter. I did the hardware part, if you want see that, just read on.

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Tiny Proto Boards

Tiny25 and Tiny2313 Proto Board

Here are two brand new boards for faster prototyping. These are especially useful for these one-off projects that need to be more permanent than on a breadboard. And they save time as most of the standard components as reset button or ISP header are already on board. Only the custom part of the project has to be soldered on the proto area. They come in two flavors, one for ATtiny25 and one for ATtiny2313 Atmel microcontrollers.

Tiny2313 Proto Board

Even a 3 AA cell battery holder with on/off switch is included in the kit. There also two new how-tos with detailed step-by-step instructions, Tiny25 Proto Board Howto and Tiny2313 Proto Board Howto.

You can grab a full kit at the Tinker Store (sorry, shop is closed), if you like.

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Fireflies in Elektor

Yay, here is my second article, this time published in the famous Elektor magazine. It’s about the synchronizing fireflies.

I met Jerry at last years HAR2009 and we chatted about the fireflies and all things electronics. He works for the Elektor magazine in the Netherlands and asked me, if I would like to publish an article about the fireflies. And here it is. Thanks Jerry, for making this possible!