Keypad security with 8051 Microcontroller

This project interfaces famous Microcontroller AT89C51 with LCD 16×2 with 3×4 Keypad. This project asks the user to enter password to unlock the lock or light up the LED. Password security via keypad can be very productive you can just put a security lock outside your door and use a servo motor to unlock the door if the user enters a correct password. However, in this project we use a simple LED if the user enters a correct password LED will glow else not. To see how to interface a simple keypad with LCD using AT89C51 please visit here....

KeyPad Interface with AT89C51 and LCD

This simple project tells you how to interface 4×3 phone keypad with famous 8051 Microcontroller AT89C51 and displays the numbers on LCD 16×2 If you want to know how to interface LCD with 8051 Please visit here. Keypad acts as a Matrix switch as shown below: These switch matrix is a combination of switches in rows and columns. Now if we want to detect what switch is pressed we will scan rows and columns. Lets say that we put all rows of the matrix on a digital HIGH by using Microcontroller and then scan each column for a pressed key....

Scroll text on DOT Matrix 16×8 display using 8051 Microcontroller AT89C51

A dot-matrix display is a display device used to display information on machines, clocks, railway departure indicators and many other devices requiring a simple display device of limited resolution. The display consists of a dot matrix of lights or mechanical indicators arranged in a rectangular configuration (other shapes are also possible, although not common) such that by switching on or off selected lights, text or graphics can be displayed. A dot matrix controller converts instructions from a processor into signals which turns on or off lights in the matrix so that the required display is produced. A dot Matrix...

Interface LM35 Temperature Sensor with 8051 (AT89C51)

This simple project interface LM35 which is a very common Temperature Sensor giving high precision reading in terms of Analog Voltage with most popular 8051 Microcontroller AT89C51. LM35 gives analog reading and microcontroller process digital data so we have to use a midway converter from Analog to Digital i.e. AD0804 and display the result of a temperature on LCD. Temperature Sensor (LM35): LM35 looks like a transistor it will give you temperature in Celsius in terms of millivolt. For example if the temperature is 25 C its output will give you 0.25V provided that you must supply at least 1V to...

Turn Relay ON or OFF using 8051 Microcontroller AT89C51

A relay is an electromechanical switch which is used to turn ON or OFF any circuit by using Electromagnet. It is just like practical switch which is drived electronically. By using Electromagnet in Relay we actulay provides isolation hence Relays can be used to power ON or OFF a heavy AC current machine etc. Relays have different ratings and different properties which are not a part of this topic. Relays and Microcontroller: Microcontroller are intelligent devices but they can’t switch ON or OFF your room fan as they can’t handle heavy current so we use relays to do so....

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