"Clock" Project

In this book, I have presented three different clock circuits. In many ways, this is the one that I like the best because it emulates an analog clock. As I indicated in the text, this clock had been sitting on my desk at work for over five years, keeping perfect time and I never had to worry about its operation. It can be a bit of a bear to wire, but the results are really worth it. Note that this application uses a low-voltage PICmicro® MCU which is run from a lithium battery when the mains power is lost.

Click Here to look at the application's source code.

The circuit used for this application is given in the pdf file that you can look at Here.

The bill of materials for this application is:

Part Description

U1 7805 +5 Volt Regulator

U2 PIC16LSF84-04/P

U3 - U7 74LS154, 4 to 16 Demultiplexor

X1 32.768 KHz Watch Crystal

CR1 - CR2 1N914 Silicon Diodes

D1 - D72(D84) 5 mm Red LEDs

R1 - R2 10K, 1/4 Watt Resistors

R3 - R74 220 Ohm, 1/4 Watt Resistors

C1 - C2 10 uF, 35 Volt Electrolytic Capacitors

C3 - C8 0.1 uF, 16 Volt Tantalum Capacitors

J1 2.5 mm Power Plug

SW1 Momentary On Pushbutton Switch

Battery 2.8 Volt Lithium PC Backup Battery

Miscellaneous Breadboard Prototyping System, Wiring, AC/DC Power Supply