Touchless Door Bell (268)

Touchless Doorbell system is divided into multiple blocks, five in total, Microcontroller block, Sensor block, Amplifier block, speaker block and the power supply block. At the center of all is the micro-controller module. This is the brain of the system it does all the computational work required for the working of the Touchless doorbell. All the calculations required to detect the press of the doorbell are done by the micro-controller. When the bell is pressed, the micro-controller also generates the melody for the doorbell. The Sensor module is used to detect the presence of an obstacle in front, here it detects the human hand. It is connected with the microcontroller, to send necessary data to perform the distance calculations required to detect the press of the bell. The Microcontroller communicates with the sensor to detect the presence of an obstacle. Once detected the microcontroller operates the speaker to produce a pleasing doorbell tune. Since the signal voltage produced by the micro-controller is low, an amplifier is used to boost the signal so that the speaker is able to produce a loud and clear sound. A DC power supply is used to convert mains voltage 220 – 240V AC to usable 5V DC voltage for the doorbell unit. The Power supply works by stepping down the high mains voltage to a lower level. Then this low AC voltage is rectified, filtered and regulated to stable DC voltage. All the blocks including the micro-controller, sensor and the speaker-amplifier are powered by the power supply module.