Unusual clocks are a common sight in Elektor Electronics. The version described here is inspired by the binary clock showcased in the new Museum of Mathematics in Gießen, Germany (which is not yet on display). Despite its origin, this clock is perfectly suitable for an ordinary living room setting. However, to enhance readability, the hours, minutes, and seconds are divided into units and tens, resulting in six columns: tens of hours, units of hours, tens of minutes, units of minutes, tens of seconds, and units of seconds. These values are read row by row from top to bottom: one, two, four, and eight — following a binary pattern. With a bit of practice, it becomes possible to quickly and effortlessly read the time at a single glance.
Power Supply and Clock Signal
The circuit operates on a supply voltage sourced from a simple mains adapter, providing an AC output voltage of 8–15 V with a maximum output current of 300 mA. It’s crucial that the voltage remains in AC form, as the microcontroller utilizes the frequency of the AC voltage (50 Hz) as a stable clock signal for long-term accuracy.
Multiplexed LED Display
Due to the limited output ports of the PIC16C54 microcontroller, driving each LED individually would necessitate additional components. To overcome this limitation, the LED display is multiplexed. Although the LEDs have low current ratings, they appear bright due to significantly higher current pulses than their rated values. Buttons S1 and S2 enable time setting functionality.
User-Friendly Time Configuration
Pressing S2 initiates the setting menu after a brief LED test (where all LEDs illuminate). The first column’s value can be adjusted using S2, progressing to the next column with S1. This sequential configuration continues until the final column, exiting the setup mode. The clock resumes operation with the newly set values.
Convenient Circuit Board Design
A printed circuit board layout tailored for the binary clock simplifies component fitting. Nine wire bridges are essential, with one situated beneath the microcontroller necessitating a socket. During LED installation, soldering only one lead initially allows alignment adjustments. Once aligned, the remaining leads are soldered. The board can be presented without an enclosure or housed in a small plastic case. Opting for a transparent enclosure eliminates the need to drill LED holes, enhancing practicality.