Painting a wall with light using water as ink

This art installation uses a fantastic concept. The wall can be painted using water as ink which lights up a huge grid of white LEDs. This offers a very wide range of interactive possibilities since water can be applied in so many ways. Grab a paint brush, wet your finger, use a squirt gun, or mist with a spray bottle and the lights will tell you where you hit the wall.

We’re hoping a reader who speaks both French and English might help out by posting a translation as a comment on the prototyping video. In it, [Antonin Fourneau] shows off the various prototypes that led to the final product and we’d love to know what he’s saying. But by seeing the prototypes, then watching the English promo video after the break we can make a pretty good guess.  The boards have a hole that fits the flat-lens LEDs perfectly. This creates a mostly water tight seal to keep the liquid on one side while the leads are safe on the other. The water side has squiggly pads which allow droplets of water to complete an electrical connection.

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Making a smaller keyboard

The keyboard on [Marek’s] laptop stopped working. He didn’t want to buy a replacement so he decided to start using an external keyboard. But hauling around a full 104-key model is a bit of a pain so he decided to make himself a shorter keyboard. He basically chopped off the 10-key pad on the right side of the board. This had the unexpected consequence of removing the screws that hold the top and bottom of the case together so he ended up adding a few extra screws to shore it up. You may be wondering how the key matrix still works if a portion of it has been cut off. [Marek] used the simple trick of folding the extra part of the membrane over and covering the unused contacts with some tape.

If you try this you should consider getting rid of the directional arrows and editing keys as well. There must be a way to map those keys elsewhere. Perhaps the half-qwerty keyboard hack will give you some inspiration for that.