Vermes
Advanced Member level 4
Presented construction is a simple alarm clock based on microcontroller Atmega8. It uses 7-segment displays (30x15mm). The system can be easily made of elements desoldered from other devices, so it may be really cheap. The PCB was designed in Eagle, drawn on laminate with a marker and etched.
Too little space in the housing may be problematic. You can connect the display to the board using cables, as shown in the following picture.
Time is measured in timer2 in asynchronous mode on quartz 32,768kHz. Processor is clocked by an external oscillator 8MHz. Program was written in Bascom.
Pictures:
Diode next to the display indicates state of alarm: on/off.
Link to original thread (useful attachment) - Zegarek na avr z budzikiem.