You can build one multifunctional project by using just 128 LEDs, arranged in a matrix order of 16X8. This special project will not only operate as a real-time digital clock, but will also be used as temperature meter. One such design is shared by one Embedded-lab’s member as – Real-time clock and Temperature display on 16×8 LED Matrix. The major components used for his build are:
PIC18F2550, that controls the columns of the display
A6276, a 16-bit serial input, constant current latched LED driver
74ACT164N, 8-bit serial-in parallel-out shift register for controlling the rows
BC337 transistors for providing the required current to drive the rows,
A DS1320 that serves as the external real time clock,
LM35, precision centigrade temperature sensor.