I made a smart dustbin using arduino, servo motor, & ultrasonic sensor. It worked pretty well for a few number of days. But once I don't know how but the Arduino 'ON' light started to become dim and switched off. I used a 9V HW battery. So I decided to plug in my arduino with a 7V AC charger, still no luck, the arduino did not turn on nor the ON light. Then I plugged the arduino to my PC, the ON light turned on for 2 to 4 seconds and switched off. I realized it became too when I touched the usb port. The ATMEGA chip did not become hot. Please help?