Hacking a Disco Laser

hacked laser disco

[Mark] was looking for a cheap disco laser projector for parties, and he found one. Unfortunately for him, the advertised features were a bit lacking. The “sound activation mode” was merely an on off circuit, as opposed to it actually being controlled by the music — he set out to fix this.

Taking the unit apart revealed a very convenient design for hacking. All of the components were connected to the main PCB by connectors, meaning the laser driver board was completely separate! He replaced the PCB completely using a prototyping board, an Arduino pro mini, a microphone with a simple preamp, a rotary encoder, and a MSGEQ7 chip to analyse the levels. Oh, and a MOSFET to control the motor via PWM output. It even ended up being close to the same size as the original!

If you happen to have one of these projectors and want to fix it too, he’s posted the source code and circuit diagram on github.

After the break, check out the before and after video. It’s still a cheap disco laser projector, but at least it works as advertised now!

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Human Asteroids makes you a vector triangle ship


In 1979, [Nolan Bushnell] released Asteroids to the world. Now, he’s playing the game again, only this time with the help of a laser projector and a Kinect that turns anyone sitting on a stool – in this case [Nolan] himself – into everyone’s favorite vector spaceship. It’s a project for Steam Carnival, a project by [Brent Bushnell] and [Eric Gradman] that hopes to bring a modern electronic carnival to your town.

The reimagined Asteroids game was created with a laser projector to display the asteroids and ship on a floor. A Kinect tracks the user sitting and rolling on a stool while a smart phone is the triangular spaceship’s ‘fire’ button. The game is played in a 150 square foot arena, and is able to put anyone behind the cockpit of an asteroid mining triangle.

[Brent] and [Eric] hope to bring their steam carnival to LA and San Francisco next spring, but if they exceed their funding goals, they might be convinced to bring their show east of the Mississippi. We’d love to try it out by hiding behind the score like the original Asteroids and wasting several hours.

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Playing MAME Games on a RGB Laser Projector

MAME Laser Projector

Vector based displays were used for arcade games in the ’70s and ’80s. A typical CRT uses raster graphics, which are displayed by deflecting a beam in a grid pattern onto a phosphor. A vector display deflects the beam in lines rather than a full grid, drawing only the needed vectors. Perhaps the best known vector game is the original Asteroids.

[Jeremy] built up a RGB laser projector, and wanted to run some classic arcade titles on it. He started off by using the XMAME emulator, but had to modify it to communicate with the laser and reduce flicker on the display.

To control the laser, a modified version of OpenLase was used. This had to be enhanced to support RGB color. The modified sources for both the MAME emulator and OpenLase are available on Github.

[Jeremy]‘s friend, [Steve], even got a vector based game that he wrote working on the system. “World War vi” is a shoot-em-up battle about the vi and emacs text editors.

The results of the build are shown in a series of videos after the break.

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Analog scope stands in to for laser light show

[Joey] likes to dabble in laser projection, building his own hardware and writing the software that drives it. One way that he tests his setup is by replacing the laser assembly with an analog oscilloscope. This allows him to ensure that the driver board is receiving data from the software, and translating it into the correct electrical signals to drive the motors controlling the mirrored redirection of the laser beam.

In the video linked above [Joey] walks us through this process. It starts by connecting scope probes to the digital-analog-converter card that outputs image data for the projector. From there the XY mode is used to map the two channels perpendicular to each other; the motors that these signals are meant to control have mirrors that also move perpendicular to one another. After adjusting the scale and the timebase you will see the pattern the laser dot is meant to trace.

[Joey] entered this in a Tectronix contest. There’s plenty of other interesting entries to browse though. If have an entry that you’d like to see featured, or if you come across any other interesting stuff, don’t forget to tip us off.

Sticky light


With the availability of webcams and projectors, multitouch and interactive demos have become increasingly popular because they’re so easy. Students at the University of Tokyo took a new approach that uses lasers instead. They created Sticky Light, which uses mirrors, a laser, and a single photodetector. Unlike camera-tracking setups, this system requires no visual processing. The laser moves around and bumps into dark objects, sticking to them. It can follow drawings on the table or objects in space, such as shirt designs. They also created a few basic games and a demo that makes sounds based on the movement of the spots. Video of the project after the break.

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Simple laser projector


[kap4001] built what has to be the simplest laser scanner possible. It’s two servos strapped together with zip ties plus a 5V laser module. They’re connected to a Pololu serial servo controller. The laser is pulsed by switching the DTR line. You could use it to draw images like the one above… except that’s an 85 second exposure.

Laser POV projector

[shakirfm] sent us this LED persistence of vision (POV) laser projector that can display dot matrix style text. The laser projector contains a rotating mirror assembly and 5 lasers. We’ve covered other POV projectors,but this one is a bit different. The mirror assembly rotates using two cooling fans. Controlling on/off times of the lasers along with the mirror speed, it is able to project 8×5 dot matrix ASCII text onto a surface.
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