Digital timer switches are used to control the operation of electrical devices based on a programmed schedule. This project describes a programmable digital timer based on the ATMEGA328 microcontroller that can be programmed to schedule the on and off operation of an electrical appliance. The appliance is controlled through a relay switch. This timer switch allows you to set both on and off time. That means, you can program when do you want to turn the device on and for how long you want it to be remained on. The maximum time interval that you can set for on and off operation is 99 hours and 59 minutes. The project provides an interactive user interface using a 16×2 character LCD along with 4 push buttons Keywords: Relay, LCD Display (16X2), Clock Unit (DS3231). ULN 2803, ATmega-328