Photoelectric Smoke Detector
Created: Sep 17, 2014
No description available.
Smoke detector is a device incorporated on fire alarm system; it is usually installed on buildings to alarm the occupants when there is a fire (when there’s smoke, there’s fire). This provides the crucial early warning to escape injury or death in fire. This project uses optical method design; the sensing part is the photo chamber that is composed of infrared light source and a photoelectric receiver (photodiode).
The design of this project is not so complicated because of the specialized IC (Integrated Circuit) intended for smoke detection. The RE46C190 smoke detector IC provides all the required features for a photoelectric smoke detector type of electronic project with minimal external component needed. During standby mode, the RE46C190 IC is programed to check the battery condition every 86 seconds and the chamber integrity every 43 seconds. Interconnection between multiple detectors (through I/O PIN-12) is also possible; this will activate all the connected detectors when one of the units is triggered.
The 1µF capacitor should be located as close as possible to the device power pins, and 10µF capacitor should be located as close as possible to VSS. Schottky diode must have a maximum peak current rating of at least 1.5A. For best results, it should have a forward voltage specification of less than 0.5V at 1A and low reverse leakage. Also, the 10mH inductor must have a maximum peak current rating of at least 1.5A. With the IC’s very low power consumption, this project only requires a three-volt DC power supply (simply use a 3 volt battery).