Fancy a time piece with a difference? How about one that displays the current time using six columns of LEDs to display the tens and units components of the hours, minutes and seconds as binary values.
The circuit is based on a single 28 pin PIC 16F882 device which keeps the time, updates the display and handles manual adjustment. The jack plug on the right side connects to a 9-12V DC (200-500mA) power supply (not shown).
A 32786Hz watch crystal is used to derive the timing for the circuit. The PIC's Timer1 module is configured for external clock input and is used to generate a 1Hz interrupt that updates the current time value. Each of the 20 LEDs used to display the time has its own current limiting resistor and two push buttons are provided to adjust the hours and minutes.
There is no back up battery so the clock resets to midnight whenever power is first applied. The prototype shown above uses green LEDs and 470R load resistors instead of the red LEDs and 330R resistors show on the schematic.
You can download the detailed project materials here:
| Schematic: | schematic.pdf |
| PCB: | pcb.pdf |
| MPLAB Project: | project-2009-06-10.zip |
| HEX File: | binary-clock-16F882.hex |
