The VB serves as the front end software for sending the command to the target board through UART communication.
This project is done to move the robot front,back,left and right as per the command button selection in VB.
That is nothing but the relays that will operate the front,back,left and right functions.
You have to run the VB frontend software connect the Serial cable between PC's RS232 port and Target board's RS232 port. Download the hex file into the AVR Device and operate the relays/robot from the PC.