This mini project is really an extremely-delicate fire sensor that activates an alarm when it detects fireplace. Thermistor centered fire alarms function well when the thermistor is in close vicinity. On this circuit, a sensitive PIN diode is used as a hearth sensor for for a longer time-assortment fireplace detection. https://downloadprojecttopics.com/blog/2017/08/23/material-management-building-construction-site/