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Day/Night Triggered Automatic Door Lock Circuit

Last Updated on May 16, 2026 by Swagatam 12 Comments

darkness activated door lock circuit

In this post I have explained a simple day, night triggered automatic door lock circuit, which can be used for autonomously unlocking a kennel door during day break, and locking it when night sets in. The idea was requested by an avid reader of this blog, Mr. Norman, as given below. Design Request and Specifications […]

Filed Under: Automation Projects, Pets and Pests Tagged With: Automatic, Door, Lock, Night, Triggered

Simplest Combination Lock Circuit Explained

Last Updated on January 2, 2024 by Swagatam 14 Comments

12V solenoid lock

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, […]

Filed Under: Security and Alarm Tagged With: Combination, Explained, Lock, Simplest

Password Lock Circuit Using IC 4017

Last Updated on January 5, 2022 by Swagatam 27 Comments

4017 based password lock circuit

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 […]

Filed Under: Security and Alarm Tagged With: 4017, Lock, Password

Infrared Car Door Lock Security Circuit

Last Updated on May 16, 2026 by Swagatam Leave a Comment

IR transmitter compressed

In this post I have explained how to build a simple yet foolproof infrared based remote control, which can be used for locking and unlocking any vehicle door through a personal remote handset. The remote controlled vehicle door lock is foolproof since it works only with a specific IR frequency range, and will not respond […]

Filed Under: Automobile Electronics Tagged With: Door, Infrared, Lock, Security

Touch Operated Code Lock Switch Circuit

Last Updated on February 2, 2020 by Swagatam 11 Comments

touch code lock

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 […]

Filed Under: Security and Alarm Tagged With: Code, Lock, Operated, Switch, Touch

GSM Car Ignition and Central Lock Circuit Using Arduino

Last Updated on June 9, 2026 by Swagatam 8 Comments

gsm car central lock circuit

In this post I will show how to construct a GSM based car security system using Arduino, which can lock and unlock car’s ignition system and central lock by sending a password SMS to car from your cellphone Car theft can be a heart break; it feels like your loved one got kidnapped. It hurts […]

Filed Under: Arduino Projects, Automobile Electronics Tagged With: Arduino, Central, GSM, Ignition, Lock

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