[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.

The video’s in three parts: looking at the laser beams in action as you’d see them on a dance floor, then watching the projected images while looking at an insert of the Windows application, and then watching the steppers and mirror doing their rapid movements.

As for the expensive galvanometer scanners we mentioned above, check out this impressive laser projector that uses them. Another method is to use a spinning wheel with mirrors set to different angles, like this one that draws a marquee using a pill box as the wheel. And how about one with no mirrors at all, instead attaching the laser directly to servo motors, though that one does take longer to draw.

It’s August, and of course that means that it’s time for retail stores to put up their Christmas decorations! But seriously, if you’re going to do better than the neighbors you need to start now. [Joey] already has his early start on the decorations, with a house-sized light show using LED strips and a laser projector that he built last Christmas.

What started off as a thought that it would be nice to hang a wreath over the garage soon turned into a laser projector that shows holiday-themed animations on the front of the house. The project also includes a few RGB LED strips which can match the colors displayed by the projector. The LEDs are powered from a custom-built supply that is controlled by a laptop, and the program that runs on the computer averages the colors from the video signal going to the projector which lights up the LED strips to match the projected image. This creates an interesting effect similar to some projects that feature home theater ambient lighting.

The only major problem [Joey] came across was having to account for the lasers’ motion in the projected patterns, which was causing the computer to read false values. This and a few other laser-related quirks were taken care of with a bit of programming to make sure the system was functioning properly. After that it was a simple matter of attaching the projector to the roof and zip-tying the LED strips to the eaves of the house.

The projector is weatherproof, has survived one harsh winter already, and can be up and running for any holiday. With Halloween right around the corner, this could be a great way to spice up some trick-or-treating. Check out the video after the break to see this setup in action.