Application and design of automation communication devices — A novel design of digital doorbell

Nowadays, the doorbell style is varied and many modern bells are electronic products but most of their functions are single. In this paper, it will show a design method of the digital doorbell using Protel99 SE software. Its mainly controller is AT89C52 SCM and its input device is 4×4 keyboard, DS1302 clock circuit and AT24C02 storage circuit and ISD1420 voice circuit are its intermediate response equipments, and playback speech circuit as well as HD44780 LCD display circuit as its intermediate response equipments. The working status of this digital doorbell can be set by users themselves, besides a common electronic bell function; it also has some more new functions. Through the time of keying and different music has been set up, the doorbell user can easily distinguish different types of visitors. In addition, the doorbell can also provide some information to the visitors, in the form of voice or text. What's more, the user can query the information every time, to make sure if there are visitors or not. In a word, the doorbell is a humanized design.