Boredom + Lasers = Projector!

[Krazer], a post-doctoral researcher at MIT, loves him some lasers. When out of boredom one afternoon he hatched an idea for a laser projector, it grew until a few years later he wound up with this RGB laser for a projector — Mark IV no less.

In addition to 3D-printing the parts, the major innovation with this version is the ability to re-align the lasers as needed; tweaking the vertical alignment is controlled by a screw on the laser mounts while the horizontal alignment is done the same way on the mirror mounts. This simplifies the design and reduces the possibility of part failure or warping over time. An additional aluminium base epoxied to the projector aims to keep the whole from deforming and adds stability. With the help of a mirror for the final alignment — sometimes you must use what you have— the projector is ready to put on a show.

True to the spirit of the art [Krazer] used all open source software for this iteration, and sharing his designs means you can build your own for around $200. As always with lasers take extra precautions to protect your eyes! This 200mW setup is no joke, but that doesn’t mean fun and games are out of the question.

Raspberry Pi Zero smart projector

Smart Projector With Built-in Raspberry Pi Zero

You’ve heard of smartphones but have you heard of smart projectors? They’ve actually been around for a few years and are sort of like a TV set top box and projector combined, leaving no need for a TV. Features can include things like streaming Netflix, browsing in Chrome, and Skyping. However, they can cost from a few hundred to over a thousand dollars.

[Novaspirit]  instead made his own cheap smart projector. He first got a $70 portable projector (800×480 native resolution, decent for that price) and opened it up. He soldered an old USB hub that he already had to a Raspberry Pi Zero so that he could plug in a WiFi dongle and a dongle for a Bluetooth keyboard. That all went into the projector.

Examining the projector’s circuit board he found locations to which he could wire the Raspberry Pi Zero for power even when the projector was off. He lastly made the Raspberry Pi dual-bootable into either OSMC or RetroPie. OSMC is a Linux install that boots directly into a media player and RetroPie is a similar install that turns your Raspberry Pi into a gaming machine. You can see a timelapse of the making of it and a demonstration in the video after the break.

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Cheap Dual Mirror Laser Projector

[Stanley] wanted to make a laser projector but all he could find online were one’s using expensive galvanometer scanners. So instead he came up with his own solution that is to be admired for its simplicity and its adaptation of what he could find.

At its heart is an Arduino Uno and an Adafruit Motor Shield v2. The green laser is turned on and off by the Arduino through a transistor. But the part that makes this really a fun machine to watch at work are the two stepper motors and two mirrors that reflect the laser in the X and Y directions. The mirrors are rectangles cut from a hard disk platter, which if you’ve ever seen one, is very reflective. The servos tilt the mirrors at high speed, fast enough to make the resulting projection on the wall appear almost a solid shape, depending on the image.

He’s even written a Windows application (in C#) for remotely controlling the projector through bluetooth. From its interface you can select from around sixteen predefined shapes, including a what looks like a cat head, a heart, a person and various geometric objects and line configurations.

There is a sort of curving of the lines wherever the image consists of two lines forming an angle, as if the steppers are having trouble with momentum, but that’s probably to be expected given that they’re steppers controlling relatively large mirrors. Or maybe it’s due to twist in the connection between motor shaft and mirror? Check out the video after the break and let us know what you think.

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A Laser Effect Projector Built With Safety In Mind

There’s just something about wielding a laser pointer on a dark, foggy night. Watching the beam cut through the mist is fun – makes you feel a little Jedi-esque. If you can’t get enough of lasers and mist, you might want to check out this DIY “laser sky” effect projector.

The laser sky effect will probably remind you of other sci-fi movies – think of the “egg scene” from Alien. The effect is achieved by sweeping a laser beam in a plane through swirling smoke or mist. The laser highlights a cross section of the otherwise hidden air currents and makes for some trippy displays. The working principle of [Chris Guichet]’s projector is simplicity itself – an octagonal mirror spun by an old brushless fan motor and a laser pointer. But after a quick proof of concept build, he added the extras that took this from prototype to product. The little laser pointer was replaced with a 200mW laser module, the hexagonal mirror mount and case were 3D printed, and the mirrors were painstakingly aligned so the laser sweeps out a plane. An Arduino was added to control the motor and provide safety interlocks to make sure the laser fires only when the mirror is up to speed. The effect of the deep ruby red laser cutting through smoke is mesmerizing.

If laser sky is a little too one-dimensional for you, expand into two dimensions with this vector laser projector, and if monochrome isn’t your thing try an RGB vector projector.

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Curiously Delightful Things Done With Lasers And Projectors

Seb Lee-Delisle has built a career around large installations that use powerful lasers and high-end projects to make people happy. It’s a dream job that came to fruition through his multi-discipline skill set, his charismatic energy, and a mindset that drives him to see how he can push the boundaries of what is possible through live interaction.

His talk at the Hackaday | Belgrade conference is about his Laser Light Synth project, but we’re glad he also takes a detour into some of the other installations he’s built. The synth itself involves some very interesting iterative design to end up with a capacitive touch audio keyboard that is lit with addressable LEDs. It controls a laser that projects shapes and images to go along with the music, which sounds great no matter who is at the keyboard thanks to some very creative coding. As the talk unfolds we also hear about his PixelPyros which is essentially a crowd-controlled laser fireworks show.

See his talk below and join us after the break for a few extra details.

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Mike Harrison Exposes Hot Oil And High Voltage Of Ancient Live Projector

It’s amazing how quickly a technological pivot will erase the existence of what was previously a modern marvel. A great example of this is the live video projection technology known as the Eidophor. In the beginning there was film, and if you shined a light through it followed by a set of lenses you could project an image for all to enjoy. But what if you didn’t want to wait for film to be developed? What if you wanted to project live video, or real-time data for a room full of people who could not be served by even the biggest of the cathode-ray tubes of the time? This question led to the development of the Eidophor whose story has been all but lost.

Mike Harrison is trying to revive the details of this amazing engineering feat and presented his findings during his talk at the Hackaday | Belgrade conference. Mike is interested in technology that is “impractical, ridiculous, absurd, or stupidly expensive” and the Eidophor certainly ticks all of those boxes. Check it out below and join us after the break where we’ll touch on the myriad challenges of developing projection technology based on hot oil and high voltage.

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Quieting A Cheap LCD Projector

There’s an old saying along the lines of “You pay peanuts, you get monkeys”. That’s true of technology, too, but a good hacker can sometimes teach an old monkey new tricks. [Heye] bought an LCD projector for $60 off AliExpress, and it turned out to be rather noisy: the air fan that sucked in air to cool the LED light source made a whooshing noise.

No surprise there, but rather than give up, he decided to see what he could do about the noise. So, he took the projector apart. After some excavation, he realized that the main source of noise was the input fan, which  was small and partly covered. That’s a recipe for noise, so he cut out the plastic grille over it and mounted a larger, quieter fan on the outside. He also designed and 3D printed an external hood for this larger fan. The result, he says, is much quieter than the original, and still keeps the LED light source fairly cool. It’s a neat hack that shows how a few hours and a bit of ingenuity can sometimes make a cheap device better.

Projector hacks are a staple here. And our favorite? Swapping out the light source for a candle.