COMPUTER CONTROLLED WIRELESS VEHICLE

In this project, we will learn How to design a PC controlled wireless robot with AVR ATmega16 microcontroller using 433MHz RF circuit. Here, we will use the PC keyboard as the input device and the 433MHz RF circuit to drive the robot wirelessly in different direction and we will display the direction of movement of robot in the PC. PC will send the signal (ASCII value of pressed key value) to the ATmega16 microcontroller through its serial port. But current generation PCs and Laptops do not have serial port in them, so we will use one USB to Serial converter cable which will create a virtual serial port in the PC /Laptop.

Again, the output of USB to Serial cable can not be connected to microcontroller directly as the output voltage of USB to Serial Cable corresponds to RS-232 level. But the ATmega16 microcontroller needs TTL/CMOS voltage levels. For this, we will use MAX-232 voltage converter which will convert RS-232 voltage level to TTL one and vice-versa. The ATmega16 microcontroller will read the serial output of MAX-232 through its USART and it will process it to know which key of the PC keyboard is pressed. After knowing which key of the PC keyboard is pressed, the ATmega16 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 and it will send the direction of movement of robot to PC also (direction of robot will be displayed in PC). 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 robot to drive the robot in the desired direction. The control keys for the robot are F or f, B or b, L or l, R or r and S or s to drive the robot in forward, backward, left, right direction and to stop it respectively. Now, press different keys from the PC and drive your robot wirelessly as you want.

Control Keys

Robot Direction

F or f Forward B orb Backward L or l Left R or r Right S or s Stop