In this post I have explained a GHz microwave radar security alarm circuit which is designed to detect an intruder within the critical zone only while it’s moving, static objects produce no effect for the sensor. Using Doppler Sensor KMY24 In the previous article I have explained about a microwave Doppler radar sensor module KMY […]
Security and Alarm
Touch Operated Code Lock Switch Circuit
This touch operated electronic door lock can be used for locking any entrance through a touch keypad. The lock’s touch feature is foolproof and impossible to crack since the touch function is required to be on 3 programmed pads together or simultaneously, otherwise the lock doesn’t respond. It is a lot convenient to open a […]
SMS Based Laser Security Circuit
In this post, I will show how to construct a laser security circuit which can send SMS alert to owner of the property or anyone else and activate loud alarm to deter the crook, which can be interfaced via relay. We always fear about crooks especially when we leave our property alone, this where security […]
Key Finder or Pet Tracker Circuit
Pets and kids (under 4) have one thing in common, they are curious by nature and love venturing into unknown zones ending up in some sort of mess or trouble. Pet or kid tracker equipment which are quite similar to a key finder circuit were specifically designed for solving this issue, here I have explained […]
RFID Security Lock Circuit – Full Program Code and Testing Details
In this article we will see how an Arduino based RFID reader circuit could be used for controlling a relay, which in turn could be used in security door lock applications. Overview If you haven’t yet checked the previous RFID article, please go ahead check it out, it covered the basics of RFID technology. We […]
Earth Leakage Indicator Circuit for Detecting Current Leakages in Ground Wires
A simple earth leakage indicator circuit discussed here can be used for getting some very useful results regarding current leakages from an appliance body into the earth pin. The idea was requested by Mr. SS kopparthy. The circuit of the proposed earth leakage indicator is shown in the figure below. Each such unit may be […]





