SprayPrinter Paints Your Wall, One Pixel At A Time

SprayPrinter is a neat idea. You download a cellphone app, point the camera at a wall, and sweep the wall with a spray can fitted with a (Bluetooth? WiFi?) remote-controlled valve. The phone knows where the nozzle is, and sprays a dot whenever it needs to “paint” the picture of your choosing on the wall.

sprayprinter-estonia-designboom-002-818x500While we’re not sure that we have the patience to paint our walls this way, it’s a cool effect. But even more, we love the idea of using the cellphone camera for location sensing. Many robotics applications do just this with an overhead camera.

Of course, we’d love more detail about how it’s done, but it’s not hard to guess that it’s either a bit of machine vision in the phone, or simpler still, that the spray-can housing has IR LEDs inside that the phone can lock onto. Indeed, the prototype version of the product shown here does look like it has an LED on the opposite side from the orange nozzle.

It wouldn’t be hard to take this to the next level, by adding enough IR LEDs that the camera in your phone can sense orientation as well as location. Heck, by measuring the distances between LEDs, you could probably even get a rough measure of depth. This could open up the use of different nozzles.

Thanks [Itay] for the tip! Some images courtesy SprayPrinter, via designboom.


GPS without GPS

Open Electronics just released a neat little board that can place you on a map without using GPS.

The board works on the basic principles of a cellphone network – the ‘cell’ network is a series of towers that are placed more or less equidistant to each other. Save for the most desolate parts of the country, a cell tower usually communicates with a phone one or two miles away. Usually, several cell towers can be seen, so the position of a cellphone can be pinpointed to within 200-350 feet. Translating cell towers to latitude and longitude is easily done by querying a Google database that was created for the mobile version of Google Maps.

The board itself is a PIC18 microcontroller and a SIM900 GSM module. The firmware available at Open Electronics is pretty impressive – all communication to the board is handled through SMS and the phone can report it’s location to 8 other phones.

It’s pretty impressive to think the same technology that caught [Kevin Mitnick] is now available to the masses. We’re wondering what Hack a Day readers would use this for, so if you have an idea leave a comment.