Propeller Clock on a Mirror.

 

Mechanics of the clock.

To start building this clock I needed to select the proper motor. I used a motor from a DC fan. The advantage of this type of motor is that is runs very quiet because it is a brush less motor with ball-bearing. It also runs at 3000 rpm or 50 revolutions per second. This results in a very stable image with a 50Hz refresh. Afterwards I found out that 50Hz is a bit over the top. The large rotor-arm, spinning at 3000rpm, makes to much noise. I had to lower the speed of the motor and find a compromise between noise level en image flicker. 

    

The fan was carefully disassembled. Making sure not to loose any part as I would need them to re-assemble to motor. On the picture you can see, from left to right, the rotor with blades, one ball-bearing, washer, spring, stator, second ball-bearing, small washer and clips.

The plastic blades from the rotor are removed and some insulation tape put around the metal case. Then 150 windings of cu wire where coiled up and fixed with glue. On the top of the rotor I made four threaded hole to later fix the rotor-arm with the leds and electronics.

Most of the plastic frame on the stator was milled away. A sleeve was made large enough to fit the rotor (with coil) and now 100 windings cu wire where coiled up. This sleeve was then glued to the stator frame. In the picture below you can see the assembled motor. We now have a motor with a transformer to deliver power to the rotating electronics.

Later on the rest of the plastic frame was also removed. The clock get is very nice finishing touch by using a mirror. For that I drilled a small hole in the mirror for the wires. Six wires in total: 2 motor, 2 index led and 2 trafo coil. The motor was then glued on the mirror.

The rest doesn't need much explaining, just have a look in the picture gallery. You can click on any of the pictures to have a larger view.