3.2.5.1 Welcome Doormat with Multiple Force Sensing Resistors

When any visitor steppes on a smart doormat, it notifies the user by turning ON the buzzer, eliminating the need for the visitor to ring a doorbell. The multiple force sensors are usually placed underneath a doormat at its four corners and the center.

A pressure change will happen when any guest or visitor steps on the doormat and is detected by scanning the five force sensors placed below the doormat.

Conventionally, the ADC scans different channels periodically to detect changes in any sensor outputs from the array of multiple sensors, and the CPU takes the required control action, requiring CPU intervention and more power consumption from the microcontroller.

This feature can also be used in capacitive touch sense applications and allows the designers to apply innovative strategies to implement user interfaces, improve response time, and reduce power consumption.