Password Based AC Mains ON/OFF Switch CircuitĀ 

In this post we are going to construct a password based mains ON/OFF switch circuit, which can turn ON and OFF the AC mains supply, only when correct password is entered. This prevents the danger of electrocution of the technician who might be currently working with the high voltage lines and equipment. By Girish Radhakrishnan … Read more

Mains High Low Voltage Protection Circuit with Delay Monitor

The post explains an upgraded version of my previous mains 220V/120V high-low voltage cut off protection circuit which now includes a delayed restoration of power for the load with 3 LED power status indicators. The idea was requested by one of the dedicated members of this website. The Request Dear Swagatam, I just followed you’re … Read more

GSM Fire SMS Alert Circuit using Arduino

In this article we are going to construct a GSM fire alert circuit system using Arduino and DHT11 sensor, which will alert the user via text message (SMS), regarding a fire hazard within the premise where it is installed. By: Girish Radhakrishnan Using DHT11 Sensor We are using DHT11 sensor for sensing unusual temperature rise … Read more