Seb Lee-Delisle: IRL

Orde Saunders' avatarPublished: by Orde Saunders

Seb Lee-Delisle was talking about computing in the real world at Mobilism, these are my notes from his talk.

Most of the time we're sat inside doing creative work but it's fun to times that by a million and do that outside. Taking things outside is complicated.

Pixel pyros is an interactive digital fireworks display. Taking computers outside is complicated, as is an 18 meter screen - there's a lot of paperwork required, putting on outside events is a job in itself. You even need an anemometer (look it up).

Massive outputs

Projectors are becoming more powerful (two 15k lumens), they need installing and calibrating. They're expensive but accessible and very good. They don't look like emitted light - like pixels are - so:

Lasers are quite powerful and RGB. One beam controlled by mirrors. Need to fill an 18 meter screen so need a bigger laser - 20,000 times brighter than a laser pointer. Adds a lot of vibrancy to the colours. Lots of maths involved, you need to move the mirrors including slowing them down before a stop as they are physical objects. 10 or 20 years ago this laser would be the size of a small car, now the size of a small suitcase.

Large outputs

Mark making - machines that draw stuff. Lunar trails - lunar lander clone in JS that also tracks what all players are doing giving an overview. Flat pack arcade cabinet with game linked to plotter on the wall.

[Bringing things into real life has different challenges but is the same kind of coding as digital.]

[The public are squishy and easy to hurt.]


Motion detection is essentially the changes between one frame and the next in a video stream.

Handing out glow sticks at dConstruct (what's that - can I have a strawberry one). Linked the motion of the glow sticks to triggering fireworks. Split the audience and get them to try and play a game of pong.

[Unfortunately I can't get into America at the moment - long story.]

Smashing conf NY. Split the audience into instruments - motion of the glow sticks in the crowd triggered the volume of the instruments with a delay of a bar. Glow sticks are a valid input method.

For pixel pyros can't use visual spectrum cameras as they will be confused by the fireworks on the screen. Use IR lights behind the screen and the crown will cast shadows to an IR camera. IR LED strips work well (but have to be waterproofed).

[It's OK, everything is under control. But I'm writing the wrong notes for my self. Me in the past is an idiot.]

800 LEDs with copper foil as touch sensors, this works on capacitance changes and can be covered with protective film. Nice to make things that are well finished. Made a scale with no wrong notes and locked them into time - still need to make people feel they have control so provide immediate feedback when the input happens.

Shooting game with laser targets. Projecting targets onto a wall with a laser and shooting at them with Nerf guns - need to detect where the dart hits the screen. Laser light screen to detect screen but lasers coming from the US got stuck in the storms so plan B: microphones. Delay in sound between different microphones (multi-laterations). Problem with this is no tolerance for real world conditions, hard to calibrate.

Laser clappy bird. The louder the applause, the higher the bird flies. It's hard! Especially when someone whistles :-)

Internet of things Stuff that talks to the interwebs (ST4i)

Take a box full of electronics and work out how to connect it tot he internet.


Why do I like doing things in real life? [Like you're not in the real world.] Best word for it is "a happening". I have a crew, projectors, lasers and a computer. The basics are much easier so try practising them yourself.

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