Vermes
Advanced Member level 4
This is a project of propeller clock. The system consists of two main parts: programmed propeller and drive shaft.
Propeller:
Microcontroller Atmega32 controls the display. 32 blue SMD diodes are controlled through 4 serial LED drivers MBI5170. Time is taken from the DS1307 (RTC). It is connected to the microcontroller by I2C bus. Image synchronization is carried out by an optoelectric sensor. 32KB of flash memory in Atmega allows support of multiple display modes.
Motor:
HDD motor drives the clock. Its main advantages are: almost noiseless operation, high speed, 6 threaded holes which allows easy attachment of the propeller. When you decide to use that motor, you have to use a special control. It is good to use dedicated driver Philips TDA5140A operating in a standard configuration (with added point of artificial centre, because the winding in the motor is connected into a triangle). Energy is transported by means of brushes to prevent complication fo the project.
Housing:
Housing is made of 15mm plexiglass. Such thick walls cause that at 50 rotations per second, the noise level produced by the clock is maintained at a very decent level. Additionally, if something breaks in the middle, no one will be hurt. The back cover is mounted on four screws. The rest of the construction is glued with adhesive ACRIFIX 192.
Video of the operation of the clock:
Link to original thread (useful attachment) – Zegar widmowy - Propeller Clock