Mobile Controlled Robot via GSM

Controlling a robot wirelessly is possible with several methods such as Remote, Bluetooth, Wi-Fi, etc. But, the controls of these communication methods are limited to certain areas, and complicated to design as well. To overcome these difficulties, we have come up with a Mobile Controlled Robot.

A Mobile Controlled Robot is a mobile device, which provides wide-range of wireless control ability to your robot unless your cell phone gets out of signal.

A general concept of mobile controlled robot is that it can be controlled from any part of the world with just an inclusion of a camera. We will definitely offer you the simplest method for developing this kind of robot in the coming days.

Now, we like to introduce the simplest technique of fabricating a Mobile Controlled Robot via GSM. As we have eliminated the use of a microcontroller, it could certainly help the beginners to feel better.

Components Used:

The components used in making this robot are easily available in electronic markets and very cost effective too. The following list provides the complete component requirements of this robot.

  • Robot Chassis
  • 12V DC Motor (60 RPM) – 2 nos.
  • Breadboard – 1 no.
  • IC L293D – 1 no.
  • IC CM8870 – 1 no.
  • IC 7805 – 1 no.
  • 9V Battery – 1 no. (Requires according to the usage)
  • Plastic Wheels – 2 or 4 nos. (Based on the chassis)
  • Castor Wheel – 1 no. (Requires only when two wheels are used)
  • 10 ΅f Capacitors – 2 nos.
  • 0.1 ΅f Capacitors – 2 nos.
  • 3.58 MHz Oscillator – 1 no.
  • 1K Resistor – 1 no.
  • 100 K Resistor – 2 nos.
  • 300 K Resistor – 1 no.
  • Universal Headphone Jack – 1 no.
  • LED – 1 no.
  • Breadboard Wires – 2 meters
  • Battery Holder – 1 no.
  • Battery Snap – 1 no.

Note: We recommend you to buy spare IC’s for all the IC specified in the component list. This could sometime help you to save your precious time if one IC fails to operate.

Circuit Diagram:

Step by Step Instructions:

1)      Power Supply:

  • Take the breadboard and connect the battery holder in horizontal position.
  • Insert the positive and negative wire of battery snap in holder.
  • Attach IC 7805 (Voltage Regulator), and place one 10 ΅F capacitor in IN & GND connection of IC 7805 and other in GND & OUT connection.
  • Take the positive supply from the battery holder via breadboard wire and place it in IN of IC 7805, and also connect its negative supply in the last row of the breadboard.
  • Place the GND of IC 7805 in the last row of the breadboard, and transfer its OUT to the first row of the breadboard.
  • As a result of these connections, +5V power is obtained in the first row of the breadboard.
  • To check the power flow path, an LED is given a positive supply via 1K Resistor.

2)      IC CM8870 Connections:

  • Connect 1st & 4th pin of CM8870 (DTMF Receiver) together.
  • Pick one 100K resistor and place one side of it in 2nd pin and other side to the 0.1 ΅f capacitor.
  • Pick another 100K resistor and connect 3rd and 2nd pin.
  • Provide GND connection to 5th, 6th, and 9th pins.
  • Couple 7th and 8th pins with 3.58 MHz Oscillator.
  • Provide +5V supply to 10th and 18th pins.
  • Take one 300K resistor, and place one side of it to 16th pin and other to 0.1 ΅f capacitor from 17th pin.
  • Connect 0.1 ΅f capacitor to the 18th pin.

3)      IC L293D connections:

  • Insert IC L293D (Motor Controller) in the breadboard.
  • Supply +5V power to 1st, 8th, 9th, and 16th pins.
  • Provide ground connection to 4th, 5th, 12th and 13th pins.
  • Attach 2nd, 7th, 10th, and 15th pins of L293D to 14th, 13th, 12th, and 11th pins of IC CM8870 respectively.

4)      12V DC motor connections:

  • Take the wire of Right Motor and insert it in 3rd and 6th pins of IC L293D.
  • Also, place the wire of Left Motor in 11th and 14th pins of IC L293D.

5)      Universal Headphone Jack Connection:

  • There are three different layers in Universal Headphone Jack such as a Sleeve, Tip, and Ring.
  • A closer view of the three layers is shown in the circuit diagram clearly.
  • Connect the sleeve to the output of 0.1 ΅f capacitor (2nd pin) in the IC CM8870.
  • Provide GND connection to the tip and ring.


After completing the construction, connect the circuit with 9V battery. Also, connect the universal headphone jack to its respective cell phone with incoming facility. Activate auto-answer mode in the cell phone before connecting it to the circuit, and enable keypad tones in the cell phone that you use to make calls.

Now, your robot is ready to operate wirelessly with GSM facility once you make a call to the cell phone connected to the robot. By pressing the number keypads in the your cell phone, you will be able to move the robot in various directions.

It is made possible with the help of Dual Tone Multi Frequency receiver (IC CM8870), in which the sleeve connection of the robot cell phone is connected to the IC CM8870. The tone received from your cell phone to the robot cell phone will be converted into binary form, and suitable output is provided by the IC CM8870 to IC L293D.

For example, if you press no. 9 in your cell phone, then the robot will move forward (as per this circuit).


Input given on your cell phone

The output obtained from the robot


Front Right


Reverse Left




Reverse Right


360 degree rotation (Right)




Reverse Right


Front Left




360 degree rotation (Left)

Catch the action of mobile controlled robot via GSM in the below video:


I hope the above information will be very useful for developing your own robot with simple and cost-effective wireless connection. If you have any suggestions or doubts regarding this robot, please do let me know by just sending a mail to

See Also:

You can leave a response, or trackback from your own site.