Voice Controlled Robot Using 8051 Microcontroller




About: Better an Oops!, than what if!.........

A voice controlled robot takes specified command in the form of voice. Whatever the command is given through voice module or Bluetooth module, it is decoded by the existing controller and hence the given command is executed.

Here in this project, I have used Bluetooth module and Android application to give voice command in the form of hex code. There are certain digits which can be sent directly to the Bluetooth module and automatically the digit is converted into its hex code.

We can use these digits as a voice command for the specified operation pre-programmed in the microcontroller.
Using digits as a voice command is easier than using alphabetical commands.

Components required :


2.40 pin female socket for controller

3. Zero PCB board

4.Crystal oscillator(11.0592 MHz)

5.7805 voltage regulator

6.Relamate pin

7.Shift register


9.Resistance (1 K-ohm)

10.Capacitor (10uF,22pF(2))

11.L293D Driver with female socket

12.16x2 LCD


14.Bluetooth module (HC-05)

15.Battery (12V)

16.Connecting wires

17.Soldering iron

18.Motors (required rpm)

19.Chasis for robot


Step 1: Chassis Design

Design a chassis according to your requirement and need.

I have designed the chassis which is a lego chassis and easily available in the market.

Step 2: Connection and PCB Design

Circuit diagram for 8051, voice controlled the robot.

The connections on the PCB is supposed to be done according to the given circuit diagram.

Step 3: Program Code and Hex Code

Assembly Code for those who want to code in assembly language of 8051.


C code for those who want to program using C language.


Using Keil Software you can write these Assembly codes for 8051 and generate hex file which is required to burn(upload) on 8051. For uploading (Burn) you need an 8051 burner, which you can find in your colleges or you can buy from the market.

Step 4: Android App

For sending voice command (1,2,3,4,5,6,7,8,9,0) to Bluetooth in the form of hex code a app is available in google play store named - Amr Voice.


Go with this link or type "Amr Voice" in play store.

Install the app > Connect Bluetooth Device > Tap on microphone icon to send your voice command.



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    5 Discussions


    6 days ago

    Why have you used shift register?sorry to say,I haven’t seen the Shift register in the provided diagram...Can u kindly mark me up?Why do we have to use the shift register and which model?


    11 months ago

    App is not available in the playstore, can you update that to my mail rv39930@gmail.com


    Answer 1 year ago

    Follow the mentioned circuit diagram to make the connections on pcb.


    1 year ago

    Interesting indeed. I used the voice app to control the lights and fans in the living room and dining room of my house. I am not sure if you encountred this problem as well in that some words are not picked up correctly and therefore your commands have to be those which are easily understood by the app to avoid errors and ambiguity.

    Good luck anyways with future projects.