Introduction: Cellphone Operated Robot

Picture of Cellphone Operated Robot

Conventionally, Wireless-controlled robots use rf circuits, which have the drawbacks of limited working range, limited frequency range and the limited control. Use of a mobile phone for robotic control can overcome these limitations. It provides the advantage of robust control, working range as large as the coverage area of the service provider, no interference with other controllers and up to twelve controlles.
Although the appearance and the capabilities of robots vary vastly, all robots share the feature of a mechanical, movable structure under some form of control. The Control of robot involves three distinct phases: perception, processing and action. Generally, the preceptors are sensors mounted on the robot , processing is done by the on-board microcontroller or processor, and the task is perfomed using motors or with some other actuators.

i want to make it clear, if you face any problem i am dere for you
, you can write comments or you can mail me at



In this project the robot, is controlled by a mobile phone that makes call to the mobile phone attached to the robot in the course of the call, if any button is pressed control corresponding to the button pressed is heard at the other end of the call. This tone is called  dual tone multi frequency tome (DTMF) robot receives this DTMF tone with the help of phone stacked in the robot
The received tone is processed by the atmega16 microcontroller with the help of DTMF decoder MT8870 the decoder decodes the DTMF tone in to its equivalent binary digit and this binary number is send to the microcontroller, the microcontroller is preprogrammed to take a decision for any give input and outputs its decision to motor drivers in order to drive the motors for forward or backward motion or a turn.
The mobile that makes a call to the mobile phone stacked in the robot acts as a remote. So this simple robotic project does not require the construction ofreceiver and transmitter units.
DTMF signaling is used for telephone signaling over the line in the voice  frequency band to the call switching center. The version of DTMF used for telephone dialing is known as touch tone.
DTMF assigns a specific frequency (consisting of two separate tones) to each key s that it can easily be identified by the electronic circuit. The signal generated by the DTMF encoder is the direct al-gebric submission, in real time of the amplitudes of two sine(cosine) waves of different frequencies, i.e. ,pressing 5 will send a tone made by adding 1336hz and 770hz to the other end of the mobile. The tones and assignments in a dtmf system shown below

Step 2: Circuit Description

Picture of Circuit Description

Figures shows the block diagram and cicuit diagram of the microcontroller- based robot. The important components of this robot are DTMF decoder, Microcontroller and motor driver.
An MT8870 series dtmf decoder is used here. All types of the mt8870 series use digital counting techniques to detect and decodeall the sixteen DTMF tone pairs in to a four bit code output. The built -in dila tone regection circuit eliminated the need for pre- filtering. When the input signal given at pin2 (IN-) single ended input configuration is recognized to be effective, the correct four bit decode signal of the DTMF tone is transferred to Q1 (pin11) through Q4(pin14) outputs.
The atmega 16 is a low power, 8 bit, cmos microcontroller based on the AVR enhanced RISC architecture. It provides the following feature: 16kb of in  system programmable flash memory with read write capabilities, 512bytes of EEPROM, 1KB SRAM, 32 general purpose input/output lines. 32 general purpose working registers. All the 32 registers are directly connected to the arithmetic logic unit, allowing two independent registers to be accessed in one signal instruction executed in one clock cycle. The resulting architecture is more code efficient. Outputs from port pins PD0 through PD3 and PD7 of the microcontroller are fed to inputs IN1 through IN4 and enable pins (EN1 and EN2) of motor driver L293d respectively, to drive geared motors. Switch S1 is used for manual reset.

the notations are :
ic1 - mt8870
ic2 - atmega16
ic3 - l293d
ic4 - cd7004
r1,r2 - 100k resistances
r3 - 330k resistances
r4-r8 - 10k resistances
c1- 0.47 micro farat capacitor
c2,c3,c5,c6 - 22pfarat capacitor
c4 - 0.1micro farat capacitor
xtal1 - 3.57 mhz crytal
xtal2 - 12mhz crystal
s1 - push to on switch
m1,m2 - 6v 50rpm motor
batt- 6v

Step 3: Software Description (the Hex Code)

the Avr microcontroller is programmed using WIN AVR
for beginners have a look at this instructable first

this is the way to pogram the avratmega 16
look at the pin diagram of atmega16 and then connect the pins acordingly (if u have any problem then feel free to write me)
i have attached the full code. The header file will be included automatically if u have installed the winavr in default location

Step 4: Working

Picture of Working

In order to control the robot, you have to make a call to the cellphone attached to the robot from any phone.
now the phone is picked by the phone on the robot through autoanswer mode(which is in the phn, just enable it).
now when you press 2 the robot will move forward
when you press 4 the robot will move left
when you press 8 the robot will move backwards
when you press 6 the robot will move right
when you press 5 the robot will stop.

Step 5: Construction

Picture of Construction
for constructing this robot, you require these components
Components used:-
" Atmega 16 microcontroller - 1
" L293d motor driver ic - 1
" Cd7004 not gate ic - 1
" 1n4007 diode - 1
" 100k resistances - 2
" 10 k resistances - 5
" 330 k resistances - 1
" 0.47mf capacitors - 1
" 0.1mf capacitors - 1
" 22pf capacitors - 4
" 3.57mhz crystal - 1
" 12mhz crystal - 1
" Push to on switch - 1
" 2 geared motors (6v, 50 rpm) - 2 (4 for four wheel drive)
" Battery 6v - 1
  • wheels - 4
  • cellphone - 2 (one urs and one can be ur frnds)
  • handsfree - 1 (for the phn on the rover)

you have to place a cellphone on the rover. The cellphone is connected to the rover through a handsfree. construct the rover in the shape which is given below.

You can get these parts from any electronic store with ease

Step 6: To Connect the Hands Free With the Circuit

Picture of To Connect the Hands Free With the Circuit

there are always two connections which come out of the phone,
these connections are
1. Tip
2. Ring
i'll prefer to use handsfree which have a straight jack (similar to the ones which we use in our ipods, but a thinner one)

the tip of that jack is called the "tip"
and the rest part behind the tip after a black strip is the ring So connect these two connections with the circuit and you will be done

Step 7: THe ENd

Follow tese steps and you are done. but if you face any problem feel free to write comments or mail me at


14102044 (author)2017-03-24

can you provide the c code for this?

Harish sajji (author)2017-03-01

please send me the c code to dump in the microcontroller

kristalhifi21 (author)2016-09-25

I am interested in this project plz send me project code at my email

NikhileshS1 (author)2016-03-16

Can u tell ma about the test point of the ckt when I will connect the one ckt in such manner plzzz

SurendraB5 (author)2016-02-25

sir i am engineering 4th sem student i saw dis dtmf based robotic vehicle video !!! i impresed nd i started working on dat bt dat vehicle is running it show taking instructions frm mobile phone !!! am not getting any help frm my project guide bt i want to submit before saturday sir can yu plz help me out imediately!!! plz sir

govinda_kumar (author)2016-02-12

can you join a camera on it

RohitR30 (author)2015-10-25

sir, can u guide me the connections of left two motors..

roboguy22 (author)2011-10-10

i need yor help,sir

TonmoyA2 (author)roboguy222015-10-13


i m very interested on ur project.i want to build it.if u help me.plz mail me your project code and some topics(

RajaC (author)2015-10-05

hello sir...

I am a student...I am interested to make this cellphone operated robotic car,so can u please give me ideas and send me the information about the assembly of the parts and the programming codes on my email id(

please kindly help me out..

Nandhue (author)2015-08-17

send me on my mail

Nandhue (author)2015-08-17

plz some information on this topic

ManishR4 (author)2015-07-10

Hello sir,

i m diploma student,and i m interested to make this cellphone operated robotic, so pls give me idea on my email id. (

Can u halp me the full circuit description this circuit so i can work on it.

karan.khatavkar.92 (author)2015-03-25

I have to make an project for science exhibition. SO i want to know the circute diagram. And want to know that is it really working.

Where will i get the required parts????

trongtin2389 (author)2015-03-22

Hi Bro!

I am from Vietnam, and work in my father's farm. I do not have much knowledge in electronic, program. Pls, help me to access to technology because I am using motor to pump water from well-water to the coffee plantation which is far away from it. I hope you can help me in how to build the device to control via mobile. If you want to make a business with me about applying technology to agriculture, we can set up via mail:


Trong Tin

kishore.kumar.1422409 (author)2015-03-10

cherry902 (author)2015-01-03

Can u mail me source code for this sir...

riya.cyril.7 (author)2014-09-11

can you please send me the program code in arduino environment????

deversh (author)2014-04-27

hi , i m using an atmega16 microcontroller for my dtmf operated car. i have used 4 motors. i cannot get my code right . please help me with the code if possible

Darwesh Murad (author)2014-04-14

Can't understand anything

Can you make it more simple for me to understand!!!!!!!!

234asdf (author)2014-02-27

sir ,pls email me source code at

pranshuaggarwal (author)2013-08-14

pls email me source code at

Ayush27 (author)2013-07-05

it has provided with a sleek idea for my bot...

mamzar (author)2013-05-16

im very interested in GMS or DTMF projects
i want to learn it
could u please mail me a soft copy of your project along with circuits and datasheet ?
thankyou so much in advance and im waiting for your reply

rani1993 (author)2013-04-22


i am working on this same project......

i use ATMEGA16 controller ic.

my problem is that the controller's port-D is connected to motor driver ic-L293D. But i don't get the output from port-D thus i don't give the output signal to both DC motors. So what is problem in my circuit??????

please give me some answer as possible........

aaaooo60 (author)2013-02-27

can you tell in depth that why you use ic4 cd7004 in this robot.

PICHIRS (author)2012-11-26

sir, when i connect the circuit to power supply the robot moves forward although the tip and ring is not connected to mobile phone.can u suggest me where the problem is???????????

mendojoel (author)2012-10-24

There is a thyristor seen in your circuit, why is it not mentioned in your circuit diagram? I also would like to know which file should i burn in my ATMEGA16 and the best possible way....Thanks :)

papo2110 (author)2012-10-12

can i purchas the board already made from you and how mych

jay8son (author)2012-09-08

Can I use Programmable IC in this project? and can I use a 3g cellphone and I will use 3G video calling so that it will have a camera integrated the landrover it? reply soon. I need your help. thanks.

jay8son (author)2012-09-08

Can I use Programmable IC in this project? and can I use a 3g cellphone and I will use 3G video calling so that it will have a camera integrated the landrover it?

vikas204 (author)2010-08-14

hey can u tell what type this hansfree is this. i have asked about this in market but no one knows about this. can u suggest me some way. rplyy soon

knagarkoti (author)vikas2042012-09-02

jus call the mobile which is connected to project and then control wirelessly.
note: mobile should be on self answering mode

santhoshreddy (author)2010-08-27

hiii can u send me da abstract of this project plz

knagarkoti (author)santhoshreddy2012-09-02

its a mobile controllable wired or wireless robot. generally it works on the frequency variation concept.

psingh37 (author)2012-08-27

sir, can u pls send me the report on DTMF based robot control . my email id is

psingh37 (author)2012-08-27

sir, can u pls send me the report on DTMF BASED ROBOT CONTROL .

king2011 (author)2012-07-02

very good great job i have more than idea about this

dakudiv (author)2012-06-13

Very nicely compiled explanation. People looking for Code for decoding DTMF using Arduino ,can refer to this link here
Our team used Microcontroller Project board from Embedded For You magazine @ AET Design Lab.

satishsaka (author)2012-06-09

plz send the soft copy to

satishsaka (author)2012-06-07

sir can u send a softy copy to this mail :

yclim90 (author)2012-05-28

i am interested in making mobile controlled robot, can u please send
me the steps and the things to use in making robot...
my email is (

Hope to get your reply soon...Thank you..

abhisheknagar (author)2012-04-23

pls help... i have made this cicuit the problem i am facing is i am not getting o\p from dtmf decoder IC i m stuck in this thing from past 1month previously it was working absolutely fine..pls help any1

ishanduraphe (author)2012-03-20

thankyou for the detailed description. i'm obliged. thanks again

asif59 (author)2012-03-19

...I am very interested to launch this project.....I work with PIC 18f452....can I build it using this ? Plz help me with ur advice....mail me :

finalpro21b (author)2012-02-24

Can u provide .hex file for Atmega32A & program That can buid in Avrstudio4 our emai is
can u provide ur email?

thejeswarareddy789 (author)2012-02-22

sir can u send me a soft copy to this mail

yadav366366 (author)2012-01-19

if i will use microcontroller 8051, instead of using there any problem in programme or circuit?

hans lal (author)2011-12-18

if i will use microcontroller 8051, instead of using there any problem because i have made the circuit using 8051 microcontroller of land rover project.?

manikantak136 (author)2011-12-17

iam interested in making mobile controled robot,so can u please send
me the steps and the things to use in making robo.please se ti to my
email (

About This Instructable




Bio: i am a technology enthusiast. just trying hard to learn more and more abut technolgy
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