link for serial

[dagakshay]

link for serial interfacing

http://www.engineersgarage.com/embedded/avr-microcontroller-projects/serial-communication-atmega16-usart

 

atmega8 relay interfacing ckt

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when you send output as logic low at PC0 the LED will not glow. when you send a logic high the relay switch and the LED will glow. apply same logic for you case instead of LED you can connect bulb/ fan/ tubelight, etc.