Programmable relay timer switch (PCB only)

Programmable relays are key elements in numerous automation applications such as automatic street light control, watering and pump control, HVAC, home automation, power plants automation in industries, etc. This DIY programmable relay switch uses PIC16F1847 (PIC16F628A can also be used) microcontroller and allows you to set both ON and OFF times. It also features cyclic option, which means you can choose to run it in a continuous loop of ON and OFF cycles. The timer can be programmed through 4 push switches. The programming menu, relay status (ON or OFF), and number of cycles completed are displayed on a 16×2 character LCD. The timing resolution of this relay timer is 1 minute. The timer also saves the previously-set ON/OFF times and the cyclic option in its internal EEPROM so that it can retain these values after any power supply interrupt. The firmware for this project is provided for both PIC16F1847 and PIC16F628A microcontrollers.