Robotics is a very interesting field of science and technology. Many advance technology is used to build robot more functional, reliable and compatible. Here we are designing a robot with will be controlled through wireless communication i.e. here is GSM communication. We will use DTMF function of GSM system to control the movement of robot. We will use DTMF decoder is like MT8870D. this is an integrated circuit which converts analog DTMF signal to digital output signal. DTMF analog signal is receive from audio output socket from any GSM mobile phone. Here digital output of the decoder is used to control the motors of robot using appropriate motor drivers like electromagnetic relays or power transistors.

Working of DTMF controlled robot can be simply explain by following block diagram. This block diagram consist of :

• Power supply
• Motor drivers
• Motors
• DTMF decoder
• GSM mobile phone
• Robot  controlling unit

1. Wheels
2. Robot body frame
3. Nuts-bots, screws and wassers
4. Printed circuit board (PCB)
5. Solder iron and soldering wire
6. Capacitors
7. Res istors
8. LM7805 IC
9. LEDs
10. DTMF decoder IC
11. Audio jack
12. Mobile phone
13. Relays
14. DC motors
15. Connecting wires

• Very simple circuit
• Low cost components
• Low power consumptions
• Long distance controlling using GSM system
• No use of microcontroller
• Very reliable
• Many controlling keys
• Fast working of keys

DTMF controlled robot  can be further improved to control more functionalities like pick and place of objects. It can be inbuilt with various sensors like infra-red proximity sensor, ultra-sonic distance measurement. Furthermore, we can also inbuilt camera and GPS tracking system to get more accurate information.