Binary Time Display with Discrete LEDs
This clock showcases a binary time display using discrete LEDs. The programming of the PIC controller in this project is remarkably straightforward, thanks to the implementation of Flowcode . The circuit design is uncomplicated, allowing construction using individual components on an experimenter’s board or by utilizing specific E-blocks modules: EB006 (1x PIC Multi-programmer), EB004 (3x LEDs), EB005 (1x LCD), and EB007 (1x switches). The circuit’s functionality is determined by the firmware, accessible for download from the article’s website .
In this setup, Port B controls six LEDs indicating seconds, Port C manages six LEDs for minutes, and Port D handles the five LEDs denoting hours. Adjusting the time is facilitated by two pushbuttons on Port E (S1 for hours and S2 for minutes). Port A is left available to drive the LCD display in 4-bit mode, ensuring a comprehensive display that not only shows the time but also indicates the day of the week (1 to 7).
Processor Reset and Zeroing of Seconds
The clock employs S3 for resetting the processor, simultaneously resetting the seconds to zero. The white LEDs maintain a current of approximately 11 mA, ensuring that the total current supplied by the PIC always remains below 200 mA. These LEDs project their illumination onto white opaque glass, which is covered by a transparent sheet adorned with printed numbers. Atop this assembly rests a clear glass pane. The LEDs are securely mounted within a frame featuring holes, ensuring their stable positioning.
Power Supply and Timekeeping Adjustments
For the power supply, a plugtop adapter with a stabilized 5-volt/400 mA output is recommended. The optional Goldcap C4 can be added if you wish to prevent the circuit from losing time during brief power interruptions. At midnight, the time advances by 54 seconds to maintain accuracy, a value that can be adjusted within Flowcode if needed. This adjustment is necessary as modifying the internal counter either adds too much or too little time. In the provided photo, the time is depicted as 21 hours (bottom row), 57 minutes (middle row), and 53 seconds (top row). Encased in a suitable housing, this circuit results in an eye-catching designer clock guaranteed to draw the attention of any visitors!
Web links: www.matrixmultimedia.com  www.elektor.com/090187