Now You See It Now You Don’t – New Tricks with Computers and Projectors
Up until a relatively short time ago, computers were the size of a small car, the components humming, whirring, and even glowing. Cathode ray tube computer monitors were obtrusive, not to mention heavy, and laptops were commonly the size of a suitcase. These days, microcontrollers the size of a credit card are being used in almost everything and LCD screens not much thicker than a coaxial cable itself grace our living rooms. So what can we do with this cheap and tiny tech?
We can do almost anything. We can make ourselves invisible, we can change how a building looks or we can create an immense light show. While the next generation of pico-projectors will take things to another level, what we have at the moment is pretty cool.
The nature of electronic projectors has spawned the creation of wearable materials designed to act as a screen for the projector, while leaving the image barely visible when projected onto clothes or skin.
This allows the possibility for impressive demonstrations whereby the demonstrator can blend into a projected background simply by putting on a lab coat made of this impressive material. The technology would also vastly improve special effects in the theatre, whereby actors would be tracked by a camera and the costumes projected onto them and morphed as the scenes changed. This technology could also open up the possibility for a sign language narrator for the deaf to sit at the corner of a cinema screen or theatre production, barely visible to those not looking out for them, but still not interfering with the picture.
3D mapping involves the use of powerful projectors, miles of coaxial cable and complex mathematics to create the illusion of actual changes on the surface onto which the image is projected. This impressive feat of electrical engineering relies on the use of a network of high quality projectors to project a replica image of a building onto the building itself, generally performed at night to make the effect more convincing.
Because the projected image is so bright when compared with the building, changes to the image seem to be incredibly realistic, since the actual building won’t be seen beneath the bright projection. 3D mapping algorithms are used to calculate the 2D points at which the image must be projected along with the appropriate shadow effects required to make an object projected onto a 2D surface appear to exist in three dimensions. With the advent of higher resolution projectors, more powerful computers, and sophisticated 3D scanning apparatus, the area of 3D mapping is becoming a more and more prevalent feature of concerts and public demonstrations, and is used today to promote films and products to great effect.
For years, enthusiastic hobbyists have speckled their house with Christmas lights but now that you can wire everything up to a microcontroller, you can control each light individually and set up some pretty complex sequences.
By timing these lighting systems to sync with the music, you have something that can get millions of views on YouTube. Coaxial cable can often be run outside leading to a set of speakers to complete the effect. These cables are tough enough to be popped under a flowerbed or gravel driveway, and still give superb sound quality. Loading your microcontroller with specifically designed MIDI files can be one way to achieve this effect, but imagine the look on your friends’ faces when they discover their karaoke microphone is controlling your lights (although that might be pushing your neighbors patience a bit too far).
These lights aren’t just for Christmas and a similar system could be used for the ultimate Halloween haunted house, simply replacing the lighting with smoke generators and actuators for a pop up skeleton. Instead of music, creaks, groans and screams would be better MP3’s to have and the microcontroller means that the entire thing can be set off with a pressure sensor.
With modern electronics becoming less expensive and more prevalent, electronic tricks are evolving and with some standard parts and your trusty pair of wire strippers, you can put on an amazing show like never before.
Written by: The quest to build the best haunted house in Sioux City made Floyd Johnson begin learning electronics after 20 years in the military. The skills were transferable, although he now uses pressure plates and tripwires to activate model vampires, doors and sound effects. Floyd begins preparing as early as August, so if you see him under the decking with a digital multimeter, don’t step there when Halloween comes around.