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4X4 Keypad Controlled Wireless Wheel Chair with ATmega32 using 433MHz RF for Physically Handicapped

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In this project, we will learn How to design a 4X4 Keypad Controlled Wireless Wheel Chair with AVR ATmega32 Microcontroller using 433MHz RF for Physically Handicapped. Here, we will use the 4X4 keypad as the input device and the 433MHz RF circuit to drive the wheel chair wirelessly in different direction. Also, we will display the direction of movement of the wheel chair in a 16X2 alphanumeric LCD. The ATmega32 microcontroller will read the 4X4 keypad output. After reading the 4X4 keypad output, the ATmega32 microcontroller will process the keypad output value to find pressed key value. According to the pressed key value, the ATmega32 microcontroller will send the required 4 bit signal to the HT12E encoder of RF transmitter circuit. The HT12E will encode the 8 bit address and 4 bit data given to it and then it will transmit the encoded signal serially to the RF module. The RF module will transmit the encoded data and address wirelessly.

At the receiver end, the RF receiver module will receive the encoded 4 bit data and 8 bit address. Then, it will transmit the encoded signal serially to the HT12D decoder which will decode the received signal to 8 bit address and 4 bit data. After decoding, the HT12D will compare the received 8 bit address with its local 8 bit address. If the received address and the local address are same, then the received 4 bit data is sent to its output pins else the received data is discarded. The 4 bit output of HT12D is sent to the DC motor driver (L293D) of the wheel chair to drive the wheel chair in the desired direction. Also, the microcontroller will display the direction of movement of the wheel chair in a 16X2 alphanumeric LCD.

The control keys for the wheel chair are 2, 8, 4, 6 and 5 to drive the wheel chair in forward, backward, left, right direction and to stop it respectively. Now, press different keys of the 4X4 keypad and drive your wheel chair wirelessly as you want.

Control Keys	Wheel Chair Direction
2	Forward
4	Left
6	Right
8	Backward
5	Stop

Softwares Required

• Atmel Studio 6 Software
• SinaProg Hex Downloader Software
• USBasp Driver

Hardwares Required

Name	Quantity
AVR Trainer Board-100 with ATmega32	1pc
AVR USB Programmer	1pc
12V, 1A DC SMPS Adaptor	1pc
DC Motor Driver	1pc
4X4 Keypad	1pc
RG1602A 16X2 Alphanumeric LCD Green	1pc
433MHz RF Transmitter & Receiver Board	1pc
Power Supply Board	1pc
1 to 1 Connector-Female to Female	12pc
10 to 10 FRC Female to Female Connector	4pc
Wheel Chair	1pc

Video

Connection Guide

The step-by-step connection guide for 4X4 Keypad Controlled Wireless Wheel Chair with ATmega32 using 433MHz RF for Physically Handicapped is as follows