Friday, March 29, 2024

Simple Security Code Lock Circuit

By Suresh Dwivedi

efy tested

The circuit described here is an electronic combination Security Code Lock. It opens only when you press four keys in the correct sequence (referred to as a code) out of a total of eight keys installed at your entrance door. If you press the wrong key sequence, the circuit resets, and the lock will not open. The author’s prototype is shown in Fig. 1.

Security Code Lock Circuit on breadboard
Fig. 1: Prototype of the lock tested on a breadboard

POC Video In English:

POC Video In Tamil:

Security Code Lock – Circuit and Working

The circuit diagram of the security code lock is shown in Fig. 2. The circuit consists of step-down transformer X1, bridge rectifier BR1, 12V voltage regulator LM7812 (IC1), dual-D flip-flop ICs 4013 (IC2 and IC3), rectifier diode 1N4007 (D1), PNP transistor BC557 (T1), npn transistor 2N2219 (T2), 12V single changeover relay RL1, and a few other components.



WHERE IS THE REST OF THIS ARTICLE'S CONTENT?

This is PREMIUM content, which means that only
REGISTERED users of our website can read it, by logging in.

If you ARE a registered user, CLICK HERE to login.
Else, CLICK HERE to register for FREE!

SHARE YOUR THOUGHTS & COMMENTS

Electronics News

Truly Innovative Tech

MOst Popular Videos

Electronics Components

Calculators