In this project, the robot is controlled by a mobile phone that makes a call to the mobile phone attached to the robot.
In the course of a call, if any button is pressed, a tone corresponding to the button pressed is heard at the other end of the call.
This tone is called "dual tone multiple-frequency" (DTMF) tone. The robot perceives this DTMF tone with the help of the phone stacked on the robot.
The received tone is processed by the microcontroller with the help of DTMF decoder.
The microcontroller then transmits the signal to the motor driver IC"s to operate the motors.
The camera and micro-phone mounted on the robot will give the detailed information of where the robot is and who is around. The signal is then transmitted to the observer via audio/video transmitter-receiver.
The metal detector circuit mounted on the robot detects any metal object around it and transmits the signal wirelessly.