Pocket Laser Vortex of DOOOOM

Step 3 Preparing the Motor

The vortex is made by reflecting the laser beam off a spinning mirror, angled slightly away from flat. This projects the beam in a circle as the mirror rotates.

The best motor is from an old CDROM drive. Usually it's 4 screws and a bit of wiggling to get the covers off, and the tray motor is the one near the front of the drive with the drive belt on. A couple of screws to undo and a bit of desoldering and it's out!

Cut a circle of the mirrored plastic around 3/8" (1cm) diameter. It doesn't have to be perfect, but trim it to an approximate shape. I used a pair of wire-cutters to do this, but be careful not to distort the plastic.

Put a blob of hot glue on the end of the motor pulley and centre the mirror on it at a slight angle to flat. Look at the picture to see how much to angle it. Hold it in place until the glue is set.

Hold the motor and turn it on. If you're lucky the motor will spin without too much vibration. If it does vibrate, trim one of the edges and spin it up again to see if it runs smoothly. Once it's reasonably smooth, check the alignment as below.

Shine the laser at the mirror with the running motor held at 45 degrees to the laser pointer. The beam will reflect off the mirror and form a circle. Project the circle onto a flat surface and it should be around 1' (30cm) diameter at a distance of 2' (60cm),

If it is near this, all well and good. If not, carefully lever off the mirror and do it all over again. Once you have the angle right, try and reduce the vibration more by trimming the edges again.

Keep going until you're happy with the angle and the level of vibration. It took me two mirrors and half a dozen re-glueings to get mine right.