DTMF ROBOT (without Microcontroller)

About: I'm crazy about inventing new things..... and thanks a lot to instructables website which helped me to share my ideas...


In this instructable i'm gonna share my project with you ....!

Intro :-

This project is made for the project expo contest in our college (JNTUCEA)...

This DTMF ROBOT can be controlled from anywhere by using voice call..and this is our own circuit...and that too it does not include any micro-controller....!

And I also wanna show you ...you can do a lot without using microcontrollers (like arduino,pic) .... now a days by using microcontrollers students are lacking in technical skills...

Step 1: Circuit

While building our project .... we have changed our circuit seven times due to errors and availability of ICs' ...

And this is the final circuit of our project.... !


1. DTMF DECODER module

2. 4X16 decoder (74LS154) (active low outputs)

3. Chassis and geared motors..

4. Perf board

5. Dual H-bridge motor driver module (L293D IC )


1.The output of the receiver phone is fed to the DTMF DECODER using AUX cable...

2.The DTMF DECODER decodes the dtmf tones and gives the 4-binary outputs..

3. Those outputs from the DTMF decoder fed to the inputs to the 4X16 decoder using wires...becoz I want more outputs and additional outputs can be used for leds' etc...

4. The 0 output pin of 4X16 decoder is not used ... since it is always low when input is not given...

5. So we can use other 15 pins... and we have hardwired programmed the robot in such a way that

If we press 1 -- forward

2 -- reverse

3 -- right

4 -- left

6. Output 1 is fed to the forward and forward pins on the motor driver module through the diodes ...so both the motors move forward ...so that the robot moves forward..(your motor driver pins may change so just make reverse engineering )

7.Output 2 is fed to the reverse and reverse pins of the motor drive module...so both the motors move backward... so that the robot moves reverse..

8. I think you might be little bit confused by the use of diodes ... those are just used to stop the reverse flow of signal..

If you don't understand what I said just remove those diodes and see the error...

9. output 3 and 4 are connected to the forward 1 and forward 2 of the motor driver after the diodes...so if any one of the motor moves forward with another motor in off state ....the robot turns...

10. you may add extra circuit to show others what tone we just received...by connecting the audio amplifier in parallel with the AUX cable..(which is optional)

Step 2: Chassis and Geared Motors

I got this from the toy which includes both chassis and geared motors... and i love it..

you may use separate chassis and BO geared motors and wheels...

Step 3: Building Body

I have used some appropriate parts in my house to build this ..... so u can use your own parts...the finished body for the robot is shown in the 3rd pic

Step 4: Connecting Electronics and Testing ..!

In the first pic I have connected the electronics and tested.... and thanks a lot to my college which provided a lab to do this,,,

In the second pic I have attached the circuitry on the top of the robot becoz it is easy to show and easy to explain to others.... and I have made some parts to hold the selfie stick .. which holds the cell phone...!

Step 5: Finished the Project

I have kept in my mind while doing this project is that my DTMF robot should look like mars rover...

Step 6: Me and My Batchmates

In pics me and my batchmates...!

our seniors helped me a lot for finding out the components ..and more...

and naveen kumar helped me to solve the errors and designing the circuit and we have spent a lot of time working for working on that...

If we had used the internet we may have completed the project in 2 days..and we have decided that we should not use internet ... so it took 6 days to build it..

and our juniors (sravani & mahanvita) have shown a pretty much good interest in the project...



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    14 Discussions


    2 years ago

    nice project bro

    can you plz tell me where can we use this

    1 reply

    Thank you bro

    frankly ... it is a dead technology....now a days we are using internet controlled robots....

    and I just did this project to say there is no need of microcontrollers to build a DTMF robot...becoz most of the projects based on dtmf robot uses arduinos...!!!

    so I built dtmf robot without microcontrollers using logic with diodes ...

    aadesh saini

    2 years ago


    I need full circuit diagram, what are component is used full details .plz replay soon as possible. I want urgent..............

    my email ID aadeshsaini1996@gmail.com

    1 reply


    circuit diagram is in step 1.... and there is a components list !

    I don't know pin numbers of it..... just google it dude