The Breathing Bag

Breathing Bag by Fiona Banner

Artist Fiona Banner asked me to assist her studio in making an art piece. I’ll describe the electronic process of making this build in the post, coding part was relatively straightforward.

Fiona’s assistant Chris Beauregard had made a rig which blew air in or out of plastic bag depending on how a switch was set.

The idea of the art piece was to make the Fiona’s classic catalogue bag seem to breath like lungs. The problem they were having was that even though the setup with fan mounted to the back of hole in the wall with fans facing oppisites sides worked for them, they couldn’t automate it without an electronic circuit. This is where I get involved and armed with and Arduino and a bunch of research I set off to make this bag breathe, so it could be permanently displayed.

The setup started really simply with one fan, an arduino, a transistor, a diode and two power supplies (one for the arduino and a higher 12 V to run the fans). This soon came to include both fans and a lot of cardboard and tape.  Silent PC fans were used to reduce the amount of noise the piece produced. One of the other things I was interested in is seeing if I could vary the power coming in and out of the fan using the PWM out pins from the arduino. this was creating an issue though, as the hard edges of the PWM especially at lower speeds were causing the fan to just turn on and off, I decided to put in some capacitors to see if I could smooth the signal coming in with these way too big caps (this turned out to bite me later).

After I was satisfied with my wire setup I bought an empty arduino shield so I could easily make a tight package. Since this needed to be on permanent display with no upkeep robustness was important. This also meant it needed to be mounted in some sort of box and we needed solid cabling. Chris made me a box with the mounts for the cable ports. I wanted the box to be hooked up to the power supplies and the fans in a way that was portable and extendible. I picked some popular cable types that could easily be bought in different lengths and replaced each one unique to prevent hooking things up incorrectly, I picked 3.5 inch jack, phono, 1/4 inch jack and DIN 5 (commonly used for MIDI). Note that DIN 5 was hooked up to an ultrasonic sensor which ultimatley scrapped from the project.

So this was it, or at least so I thought, one of the capicitors blew on the project and I had to go off to the gallery to fix it, so I quickly made my version two of this control box. One of the things I wanted to achieve is a more simple robust design that had fewer components so fewer things that could go wrong, so I went on to remove the capicitors. Removing the caps meant I wouldn’t be able to properly use PWM to gently ramp up and down the fans, but I found in practice that the interval that breathing worked over was so short it did not really make a difference. Instead I started to emperically time how and when the fan reached full power and when I would have to pre-emptively turn off the fan to get the desired reduced blowing speed to match up with natural breathing look for the bag.

I’m happy to say that my onsite surgery was a succes and the bag was up and running again.

After this Fiona asked me to make a few more so I also ended up making a version three, which I housed myself in a more efficient PSU box.

All in all I made six of these units, I had a lot fun making them.

Art piece.


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