A electronic combination lock is a device which is designed to activate an electrical solenoid locking system whenever the correct combination of numbers are entered into an attached keypad. To build this type of electronic combination lock, normally an electronic circuit with a keypad is used. In the design I have explained in this article, […]
Security and Alarm
Password Lock Circuit Using IC 4017
In this post I will show how to construct a general purpose password based electronic lock circuit without any involvement of microcontroller. You can use this circuit for numerous applications where a basic level of security is required for turning a circuit ON. The proposed project is built using an IC 4017 and the circuit […]
3 Accurate Infrared Intruder Alarm Circuits using Photodiodes
In this post I have explained 3 simple yet accurate infrared intruder alarm circuits using an infrared transmitter and an infrared receiver module. The transmitter and the receiver photo diodes used in the two modules are aligned in line at a distance of around 2 meters within the restricted area. When a burglar tries to […]
7 Interesting IC 555 Siren and Alarm Circuits
In this post I have explained how to use IC 555 to create 7 interesting siren and alarm sound effect generator circuits. The versatile astable multivbrator configuration of IC 555 allows us to implement it for making various types of sirens and alarm circuits. This becomes possible because an astable is basically a waveform generator, […]
Simple Anti-Theft Alarm Circuit to Protect Valuable Items
This easy yet useful security alarm circuit is designed to get triggered in response to even a brief movement of the unit, causing a loud alarm sound to set off. The circuit could be attached or installed on any desired gadget or asset which needs to be protected from theft. As soon as the gadget […]
How Laser Microphones or Laser Bugs Work
A laser microphone is a security monitoring gadget in which a laser beam is used for detecting audio vibrations across faraway targets, which are normally walls or glass of homes or offices. These devices could be applied for eavesdropping with virtually no chance of getting identified or cover getting blown. Laser eavesdropping gadgets, it is […]