Raspberry Pi is an ARM cortex primarily based famous development board designed for electronic Engineers and Hobbyists. It’s a single board computer working on low strength. With the processing speed and reminiscence, Raspberry Pi may be used for performing extraordinary features at a time, like a regular laptop, and consequently it's far referred to as Mini laptop on your palm.
Step 1: Components
Raspberry Pi (with booted SD card) -1
Keypad Module -1
16x2 LCD -1
10 k pot -1
10k resistor pack(Pullup) -1
1k Resistor -1
Bread board -1
CD/DVD trolley -1
Power 5 volt -1
Motor driver L293D -1
12 Volt Battery -1
Step 2: Description
In this circuit we've got used multiplexing approach to interface keypad for input the password inside the system. Here we're the usage of a 4x4 multiplex keypad which have 16 key. If we want to apply sixteen keys then we want sixteen pins for connection to Raspberry Pi but in multiplexing method we want to apply handiest eight pin for interfacing sixteen keys. So that it's far a clever manner to interface a keypad module.
Multiplexing Technique: Multiplexing technique is a totally efficient manner to lessen variety of pins used with the microcontroller for supplying enter or password or numbers. Basically this technique is utilized in approaches - one is row scanning and other one is colon scanning. Here we've implemented a short manner of coding for the identical keypad. Please see it in programming segment of the web page.
Step 3: Circuit and Connection
Circuit of this Project is very simple which contains Raspberry Pi, keypad module, buzzer, DVD/CD trolley as gate and LCD. Right here Raspberry Pi controls the complete techniques like taking password from keypad module, comparing passwords, driving buzzer & gate and sending respective results to LCD. Keypad is used for taking password. Buzzer is used for indications and liquid crystal display is used for displaying messages or results on it. Buzzer is pushed through using an inbuilt NPN transistor.
Keypad module’s Column pins are directly related to pin 22, 23, 24, 25 and Row pins are related to 21, 14, 13, 12 of Raspberry Pi’s wringPi pins. A 16x2 lcd is connected with raspberry Pi in 4-bit mode. control pin RS, RW and En are linked to GPIO pin 11, GND and 10. And facts pin D4-D7 is attached to GPIO pins 6, 15, four and 1. And one buzzer is connected at GPIO pin 8. And motor motive force is connected at GPIO pin 28 and 29 of raspberry Pi. And a 12 volt battery is hooked up at pin 8 of L293D with respect to ground.
You may read More about this article on Circuit Digest.
Step 4: Working
Operation of this challenge is simple. While hobbyest will run the code in raspberry Pi then liquid crystal display will display a few welcome messages and after it show “A- input Password” and in 2nd line B- Change Passkey”. Now person can pick out their desire with the aid of pressing A and B on the keypad.
Now suppose user need to open gate then he/she need to press ‘A’ on the keypad after which gadget will ask for Password. Default Password is “1234”. Now person ought to input their password and after input the password one among situations achieved by way of the gadget.
1. If person input proper password then gadget will open the gate otherwise
2. Device will send command to buzzer to beep and indicates “Access Denied” at the liquid crystal display.
Now suppose consumer want to change the password then he/she want to press ‘B’ on the keypad and then lcd ask for “Current Password” or “Current Passkey”. Now Hobbyest want to enter the Current password and after input it system will fit it and carry out one among given responsibilities.
1. If person enter proper password then device will ask for “New Password”.
Now hobbyst needs to input New Password. otherwise
2. Device will drive buzzer and suggests “incorrect Password: at the liquid crystal display.
Now person needs to repeat complete method once more to Change password.
Step 5: Program
Programming is a great deal just like Arduino. Arduino feature uses classes but here we've achieved this code the usage of c programming without classes. We've got also established a wiringPi library for GPIOs.
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