Abstract:
Most common entry alert systems use sound and/or light to give notifications when someone enters through a monitored zone. These systems are however not applicable to people who are deaf and blind, along with the elderly people who are known to suffer greatly from this problem. In this paper, we report on an entry alert system suited to assist persons with aforementioned disability by utilizing the sense of smell. The system consists of a Passive Infrared (PIR) sensor, used to detect motion of an intruder through variations in radiant heat emitted by surrounding objects. An output from a Passive Infrared (PIR) Sensor triggers an Arduino Uno based on a programmable AT Mega 328P-PU microcontroller. A program developed in an Arduino Uno IDE and installed in the Arduino, directs a digital signal to a 5v relay that switches on an actuator element which in turn causes an aerosol to release a scent which can be recognized by thedeafblind alerting them of an intruder. The PIR sensor was found to have an output voltage of 3.3V and a maximum detection range of 7 meters. The sensitivity was not affected much under normal working conditions with a change of 0.8 V recorded for temperatures between 15-30OC. The system response time was found to be 0.3m/s at 20OC and 0.5m/s at 29OC for Rose perfume, 0.19m/s at 20OC and 0.25m/s at 29OC for Lavender perfume. These measurements compared well with data from MQ2 gas detector. The findings offer a novel door entry alert system that enhances security and comfort for the deafblind.
