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Password Protected PC Controlled Wireless Robot with ATmega16 using 433MHz RF

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In this project, we will learn How to design a password protected PC controlled wireless robot with AVR ATmega16 microcontroller using 433 MHz RF circuit. Here, we use the PC keyboard as the input device to enter the password and to drive the robot in different direction. The 433 MHz RF circuit will be used to drive the robot wirelessly. The password is a 4 digit number. In our case the password is “1234” which can be changed in the program. To gain access of the robot control, the user has to enter the correct password.

PC will send the control 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 a 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. And 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. First the user will enter the 4 digit password, each digit of which will be displayed in PC as star (*) and microcontroller will compare the entered password with the set password. The system will ask to enter password till the correct password is entered by the user. After the correct password is entered, the microcontroller will receive the robot control signal from PC and it will process the control signal 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 both the PC and drive your robot wirelessly as you want.

Control Keys	Appliance Status Change
1	Appliance 1 On/Off
2	Appliance 2 On/Off
3	Appliance 3 On/Off
4	Appliance 4 On/Off
5	All Appliances On
6	All Appliances Off

 

Softwares Required

• Atmel Studio 6 Software
• SinaProg Hex Downloader Software
• USBasp Driver
• RealTerm Terminal Software
• USB to Serial Driver

Hardwares Required

Name	Quantity
AVR Trainer Board-100 with ATmega16	1pc
AVR USB Programmer	1pc
12V, 1A DC SMPS Adaptor	2pc
DC Motor Driver	1pc
RS-232 Driver Board	1pc
Robot V 4.0	1pc
433MHz RF Transmitter & Receiver Board	1pc
Power Supply Board	1pc
USB to Serial Cable-Y-105	1pc
1 to 1 Connector-Female to Female	9pc
10 to 10 FRC Female to Female Connector	3pc

Video

Connection Guide

The step-by-step connection guide for Password Protected PC Controlled Wireless Robot with ATmega16 using 433MHz RF is as follows