Wednesday, April 13, 2011
This causes the resistance of LDR to increase and the voltage at the base of the transistor is pulled high due to which the supply to the COB (chip-on-board) is completed. The sensitivity of the smoke detector depends on the distance between bulb and LDR as well as setting of preset VR1.
We have not build this smoke alarm detector.
For smoke detector installation and maintenance use a near electrician.
Electronic Circuit is a good site for hobbyist also who would like to try DIY because it shared good circuits. If you have a personalized circuit requirement you may feel free to request it through the comment box or contact me.