First of all I want to thank you guys for your comments. I really appreciate it. I spent on this project about 25 USD: * electrical panel box - $3 * 4x4 Matrix keypad - $4 * 1602 LCD - $4 * ATmega328p - $4 * prototype board, buzzer, relay, 74LS164, etc. - ~$10
Hi folks, I would like to share with you my project. It is an Arduino based alarm system which consists of 4x4 matrix keypad, 16x02 LCD screen connected to board using 2-wire schematic on 74LS164 and ATmega328p.