An LED Projector As A Lighting Effect

If you had an array of high power addressable LEDs, how would you project them onto a wall? Perhaps you’d use a Fresnel lens, or maybe an individual lens on the top of each. [Joo] faced this problem when making a lighting effect using just such an array, and the solution they came up with used both.

The problem facing a would-be LED array projector is that should the lens be too good, it will project the individual points of light from the LEDs themselves, when a more diffuse point is required. Thus the Fresnel required the aid of a separate array of lenses, resin printed in one in clear plastic. From this we get some useful tips on how to do this for best lens quality, and while the result is not quite optically perfect, it’s certainly good enough for the job in hand.

The linked Printables page comes with all you need to make the parts, and you too can have your own projected LED effect. Now we want one, too! Perhaps we really need our own Wrencher signal instead.

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.