FriiSpray – Digital Infra-red Graffiti

Enabling Expression through Technology

FriiSpray – Digital Infra-red Graffiti header image 2

FriiSpray rear projection testing

January 22nd, 2009 · 2 Comments · Testing

Yesterday we set up the FriiSpray kit with a rear projection screen to test out the IR tracking. We also used the IR spraycan for the first time and all seemed to work pretty well. A vast improvement on the front projection technique.

We used stage weights to hold the screen in place and make sure it couldn’t move even if knocked / bumped into. This is to [hopefully] prevent having to re-callibrate when we are showcasing the work at events.

At first, when we were setting up the screen and callibrating the WiiMote, we were getting mysterious phantom IR signals from the room [downstairs at the #OBH]. This was throwing our callibration off and was quite bizarre. We couldn’t work out where they were coming from but reckon it could be:

- motion sensors that control the lights / energy saving

- possibly coming from the many projectors in the ceiling

- coming from some of the interactive whiteboards around the room

- possibly The Hodge meddling with our scheme + causing mischief

As we couldn’t find the source of the mysterious IR signals we resolved the problem by moving the setup to another part of the room that didn’t have any phantom IR going on. This interference is something we hadn’t considered but worth thinking about if you want to set up a similar IR-based install anywhere.

Once we had figured that issue out we got the equipment up and running without much hassle. We taped the WiiMote to the projector to stop it from wobbling / moving about – this ensured that the callibration stayed accurate for our test.

Using the spraycan was much more satisfying than the test / prototype pen and people that came to have a go really liked the fact that they could shake the can and make it rattle. We did come across some issues that need sorting out:

- the corners of the projection screen are rounded making it impractical to fill the screen with the current menu bar placement. Solutions include possible moving the bar to the bottom of the screen, or making it smaller + not to the top / bottom of the screen.

- one of the chisel tip brushes caued the FriiSpray AIR application to crash – we think that this has something to do with the changing preview outline cursor – something for Richard to look at / change.


Overall a useful testing session – found a few bugs and issues to sort out before our Ignite North presentation today.

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2 Comments so far ↓

  • darrell

    This project looks great and I’m going to use it for our forthcoming Digital Scarborough event in September. Just one thing…. when you save the image to png, where does the png get saved?

    Cheers, and well done!

  • Richard Garside

    It gets saved to the logged in user’s documents folder.

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