Here is something that will definitely catch the attention of your guests, although the project’s author wasn’t lucky enough with the WAF (Wife Acceptance Factor). A laser beam showing the time on one of your walls, an unusual clock indeed and very easy to build.

Tracking the time is done by an Atmel Attiny24 microcontroller. It feeds a PWM signal to a servo motor that rotates the laser. The laser, controlled by the Atmel and driven by a npn transistor, can be set as a continuous line or pulsating. A crystal oscillator is used for best accuracy. Connector J1 is used to set the time and for settings, using a jumper. It can be set to show hours or seconds for example. Of course you could replace this with push buttons and/or switches.

It’s best to adjust time at fixed hours otherwise you will have to count seconds to adjust minutes. Also depending on the type of servo motor you will be using you might need to play with the values of servo’s rotation span. There is a version available using the Arduino.

The code is written in C and it is very well commented and that comes in very handy if you want to add some modifications. There are some things you will have to look out for when recompiling. Circuit diagram and code are available in the project as well as pictures and a video of the sundial.

Laser Sundial: [Link]

We all know the Sony Blu-Ray replacement drive assembly for the PS3 and the Blu-Ray Laser phaser project i mentioned in a past article. So we know its possible to build a Blu-Ray Laser with one of these modules, but what makes this project better than others ? It seems the author payed a little more attention to details and added a current-limited power supply opposed to the simple resistor based design. The project also features rechargeable Li-Ion batteries with charging jack on the back and a protection circuit module for Li-Ion batteries. So you can see now that this project brought many improvements to the original one.

Blu-Ray Laser Pointer: [Link]

The idea of the project is to use two mirrors, two motors to move the mirrors, a laser pointer, and a PIC microcontroller with serial input to receive the image from the host computer and control the mirrors and laser. The image will be conditioned in and transferred by Processing. The result will be an image that looks a bit like a big POV or a red and black old style computer display. The project its still a work in progress because only control of the x axes was realized, next the author will add control on the y axes and the project should be finished.
Laser Display POV: [Link]

The basics of this design is similar with television principles: the laser beam is reflected by the mirrors placed on each face of the octagonal head creating a raster. This raster is modulated by turning on/off the laser beam. The Microcontroller board receives one pulse per rotation from the rotational speed sensor and calculates very precisely the moment for turning on/off the beam.
Mechanically scanned laser display: [Link]

DIY Laserbeam Alarm: [Via]