Alarm Clock Made from PIC

This PIC-based alarm clock was built to be programmed with a very annoying tune and a very loud voice by using a speaker.

In the design, the timer0 interrupt of the PIC is used for timekeeping which is rewritten in assembler. The texts are stored using 4-line LCD routines and tables. The tables are responsible for storing the data. The big numbers of the time with 4×4 and 3×3 sizes are displayed by the 3×20 HD44780 compatible backlit LCD. Pulse width modulation is used for alarm sound tuning as the device can be interfaced with computer for synchronization of time with the web. In PWM mode, the internal CCP1 module of the PIC is used to dim the backlight while the CCP2, also in PWM mode, is used for alarm sound.

A 20MHz crystal connected to 2 capacitors is used by the microcontroller which employs pushing switch S1 for the reset. It is necessary to have a MAX232 TTL to RS232 level converter in order to connect the microprocessor to a PC. This will be connected to 2 rows of pins connected to a flat cable containing DB9-M connector and a box connector.

Rest of the project