keypad interfacing with lpc2148 arm7 primer circuit

A Keypad Circuit That Will Convert From Decimal To BCD Decimal

When a keypad switch is pressed, this circuit reproduces its value in Binary Coded Decimal (BCD) format. A 12-keypad is used, but it can be expanded to 16 keys for Hexadecimal to BCD conversion. The circuit consists of two parts:...

Keypad-Operated Switch No.2

This is a simplified version of the Universal Keypad-Operated Switch. The design has been modified to reduce circuit complexity and the number of components required. As a result, the code is somewhat less secure; however, it remains adequate for many...

How To Build A Simple Alarm Control Keypad

Pressing a single key on the keypad energizes the relay. Entering a four-digit code of your choice de-energizes the relay. The circuit was designed to control the Modular Burglar Alarm System but can have other applications. A five-digit version of...

Keypad Controlled Switch No2

The Keypad Controlled Switch No2 Circuit operates with a 12-volt supply but is compatible with voltages ranging from 5 to 15 volts. The only requirement is to select a relay that matches the desired supply voltage. The Keypad Controlled Switch No2...

Keypad Combination Lock circuit

This simple circuit is the electronic version of the combination lock. Using the special purpose LS7220 digital lock IC, the circuit allows a 4 digit combination of your choice to activate a relay for a set period of time. This...

Alarm Circuit Using Keypad

This design circuit functions as an alarm system controlled by a keypad. The core component of the circuit is a single transistor from the BC547 series. The circuit requires a 12-key pad, which has 13 terminals; a matrix type with...

5 digit alarm control keypad

This keypad is designed for use with the Modular Burglar Alarm system, although it can be applied in various other contexts. Inputting the first four digits of a selected five-digit code will activate the relay, while entering the complete five-digit...

Enhanced 4 Digit Alarm Keypad

The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 terminals will NOT do. The Alarm is set by pressing...

keypad floating voltages

A keypad lock is being developed using a PIC microcontroller and a passive keypad with 8 pins, consisting of 4 input and 4 output pins. Each input pin corresponds to a row of numbers on a 4x4 keypad, while the...