Motor control using DTMF

Tanushree Patel, Jyoti Hazare, Tinkeshwari Bamne, Sangeeta Barde, Prof.Mukesh Sana

Department of electronics and communication engineering , shri balaji institute of technology and management betul

Keywords- Control, Motor,DTMF, Embedded systems

Abstract- This project works on the principle of DTMF tone command so received from any
phone to remotely switch and control electrical load such as agricultural pump, domestic and
industrial loads etc. In industries, the loads are spread over a large area and thus, operating
these loads is a very difficult task. In agricultural fields also, pumps and other loads are
connected over a large area and hence it is difficult for the farmer to operate all the loads and
similarly for house hold loads. Thus to overcome these problems, the proposed system has
been designed which uses DTMF technology to control the loads remotely

INTRODUCTION: - Now-a-Days Automation is playing an important role in each and Every

field such as Industrial, Home, Rural and Agricultural Areas. Security is prime concern in our
day-today life. Everyone wants to be as much as secure as to be possible. An access control
systems forms a vital link in a security chain. The micro controller based mobile operated
speed control of ac motor allows remote control of motor. This system is best suitable for
agricultural purposes, home security and automation. The mobile phones that we use in our
day-to-day life have many features that are embedded in it. The major feature that we access
is for the purpose of communicating. This paper deals with the new innovative feature of using
the mobile as a remote control. A DTMF mobile based application allows the farmers to switch
on/control their pumping sets by pressing a few keys on their mobile. Thus assisting the
farmers, the back bone of our country, in developing the agriculture sector. The farmer can
monitor and check availability of the power at the pump, switch the pump on/off and
acknowledge on/off status of the water pump from any place. To control the devices from
remote place we are using a DTMF technique. DTMF (Dual Tone Multi Frequency) is used
which converts the desired frequency in to analog signals which is received by DTMF Decoder
and given to AT89S52 microcontroller. The microcontroller is used for switching the motor
according to the frequency received by the DTMF receiver. By using this project motor can be
rotate clockwise, anti clock wise, anywhere from the planet. A 16X2 LCD is interfaced with
microcontroller to have the display. Speed controlling is also done for this motor. This project
uses regulated 5V, 1A power supply. 7805 three terminal voltage regulator is used for voltage
regulation. Bridge type full wave rectifier is used to rectify the ac output of secondary of
230/12V step down transformer.
 Figure- block diagram

DTMF (Dual-tone multi-frequency) :-

Dual-tone multi-frequency signaling (DTMF) is a telecommunication

signaling system using the voice-frequency band over telephone lines
between telephone equipment and other communications devices and switching
centers.[1] DTMF was first developed in the Bell System in the United States, and became known
under the trademark Touch-Tone for use in push-button telephones supplied to telephone
customers, starting in 1963. DTMF is standardized as ITU-T Recommendation Q.23.[2] It is also
known in the UK as MF4.
The Touch-Tone system using a telephone keypad gradually replaced the use of rotary dial and
has become the industry standard for landline and mobile service. Other multi-
frequency systems are used for internal signaling within the telephone network.
The AUTOVON telephone system of the United States Armed Forces used these signals to assert
certain privilege and priority levels when placing telephone calls.[7] Precedence is still a feature
of military telephone networks, but using number combinations. For example, entering 93
before a number is a priority call.
Present-day uses of the A, B, C and D signals on telephone networks are few, and are exclusive
to network control. For example, the A key is used on some networks to cycle through different
carriers at will. The A, B, C and D tones are used in radio phone patch and repeater operations
to allow, among other uses, control of the repeater while connected to an active phone line.
Power Supply - The output from transformer is 9V Ac we require for our circuit because all the
circuit work only DC. So with the help of rectifier we rectify & filter this signal so as to get pure
DC from this circuit. Out from rectifier & filter circuit is unregulated so by using regulator
output from this is fixed 5v is maintained by this block.

AT89S52 Microcontroller The AT89S52 is a low-power, high-performance CMOS 8- bit micro

controller with 8Kbytes of in-system programmable flash memory. The device is manufactured
by Atmel’s highdensity nonvolatile memory technology and is compatible with the industry-
standard 80C51 micro controller.AT89S52 is a powerful micro controller, which provides a
highly flexible and cost effective solution to any embedded control applications. The AT89S52
provides the following standard features: 8K bytes of Flash, 256 bytes of RAM, 32 I/O lines,
Watchdog timer, two data pointers, three 16-bit timer/counters, full duplex serial port, on-chip
oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic for operation
down to zero frequency and supports two software selectable power saving modes. The Idle
Mode stops the CPU while allowing the RAM timer/counters, serial port, and interrupt system
to continue functioning. The Power-down mode saves the RAM contents but freezes the
oscillator, disabling all other chip functions until the next interrupt or hardware reset.
DTMF Decoder 8870 Dual-tone multi-frequency signaling (DTMF) is used for telecommunication
signaling over analog telephone lines in the voice-frequency band between telephone handsets and
other communications devices and the switching center. The version of DTMF that is used in push-
button telephones for tone dialing is known as Touch-Tone. It was first used by AT&T in commerce as a
registered trademark, and is standardized by ITU-T Recommendation Q.23. It is also known in the UK as
MF4.Other multi-frequency systems are used for internal signaling within the telephone network. The
DTMF keypad is laid out in a 4×4 matrix, with each row representing a low frequency, and each column
representing a high frequency. Pressing a single key (such as '1') will send a sinusoidal tone for each of
the two frequencies (697 and 1209 hertz (Hz). The original keypads had levers inside, so each button
activated two contacts. The multiple tones are the reason for calling the system multi frequency. These
tones are then decoded by the switching center to determine which key was pressed.

Fig- Decoder

Advantages

 Wireless Control from Remote places.

 Easy of operation.

 By using any mobile possible to on/off motor.

 Speed of motor varies simple pressing remote mobile buttons.

 Display the status of current operation.

Applications

 This system can be used in industrial applications.

 This system can be employed in houses, where people often forget to switch off electrical appliances.
 This system can be used to control AC’s to set the room temperature when we are outside.

 This system can be used for agricultural purposes.

 CONCLUSIONS = This project presents a DTMF based AC motor speed control and it is designed and
implemented with Atmel 89S52 MCU in embedded system domain. Experimental work has been carried
out carefully. The result shows that higher efficiency is indeed achieved using the embedded system.
The proposed method is verified to be highly beneficial for the security purpose and industrial purpose.

Results = Speed control of motor using mobile phone is microcontroller based project work on low
voltage circuit. In this work motor speed, motor ON/Off & Load is switched from anywhere from the
world. In this if we call to our mobile circuit then following functions will be done If we press 1 then
motor will ON with Low speed around 730rpm. If we press 2 then motor will ON with MID speed around
880rpm. If we press 3 then motor will ON with HIGH speed around 1200rpm. If we press 0 then motor
will turn off. In this the speed of motor i.e. voltage control method by using mobile phone. In this work
we use DTMF 8870 IC for detecting of mobile signal pressed by caller from remote place. The mobile
output signal is RF this signal is converted in to binary digital form using this 8870 IC.

REFERENCES

[1] The 8052 Microcontrollers & Embedded systems Using assembly & C by Muhammad Ali mazidi,
Janice Gillispie Mazidi, Rolin D.Mckinlay, second edition.

[2] Power Semiconductor Application Philips Semiconductor.

[3] Digital Logic & computer Design by M.Morris Mano.

[4] www.wikipedia.com

[5] Application Note Applications of the MT8870Integrated DTMF Receiver.