GSM Based Stepper Motor Monitoring and Speed Control

(1)

ISSN (PRINT) :2320 – 8945, Volume -1, Issue -5, 2013

86

Pawan Chandra, Piyush Anand,Prabhat Chandra Chantola & Shilpi Department of Electrical & Electronics Engineering,

College of Engineering Roorkee, Uttarakhand E-mail : [email protected], [email protected], [email protected],[email protected]

Abstract – In this paper, the design aspects of an embedded device which can control stepper motor by sending a specific SMS message from a mobile phone are presented.

This controller is extremely handy at places where we have to control the ON and OFF switching of the devices but no wired connection to that place is available. GSM (SMS) controlled stepper motor is automatic control system which is capable of receiving a set of command instructions in the form of Short Message Service and perform the necessary actions like start, stop and speed control. We use a dedicated modem at the receiver module and send the AT commands using SMS service as per the required actions. The mobile unit is interfaced with microcontroller so that it takes the responsibility of reading the received commands in the form of SMS and performs the predefined tasks such as motor start, stop, motor direction and speed control.

Keywords – Short message service (SMS), Global System for Mobile Communication (GSM), AT Command, GSM Modem

I. INTRODUCTION GSM modem with simcom technology.

This Project is a very good example of embedded system as all its operations are controlled by intelligent software inside the microcontroller.GSM and GPRS based designs have developed another innovative and public utility product for mass communication. This is a Stepper Motor Control Device which control the stepper motor through messages received as SMS or GPRS Packets and also send acknowledgment of task. This devices are designed to remotely control the Stepper Motor from anywhere and anytime. This remote control Stepper motor control device is possible through embedded systems. The main aim of the project is to design a SMS electronic Stepper Motor Control toolkit which can replace the traditional Stepper Motor Control Devices. The toolkit receives the SMS, validates the sending Mobile Identification Number (MIN) and

performs the desired operation after necessary code conversion. The system is made efficient by SIMs so that the SMS can be received by number of devices boards in a locality using techniques of time division multiple access. With this in mind, we have designed the project to work with sim300 technology.

II. SYSTEM ARCHITECTURE

As shown in figure 1 the wireless transference of monitoring massages discussed in this paper is built on the SMS of the GSM network. The SMS can be sent to any mobile user of any any service provider with no or minimum charge. This system is designed using a GSM modem. The GSM modem is configured as a receiver.

The SMS sent by the user is written in a particular format. The controller receives the message and decodes it and identifies the task to be done and the SMS received by the controller is decoded, and the proper message is displayed on the LCD by the microcontroller. Here is the block diagram of the complete system.

Fig. 1: System Architecture TRANSMITTER

UNIT

GSM MO DEM

MICRO CONTR OLLER LCD

MOTOR DRIVER

RECIEVING UNIT

MOTOR

(2)

87 III. HARDWARE USED

AT commands supporting GSM modem 89S52 Microcontroller

LCD: 16x2 characters RS 232 converter: MAX 232 Motor Driver ULN2803 Voltage Regulator 7805 Diode

GSM Phone Stepper Motor

IV. SOFTAWARE USED KEIL μ- VISION 3.0:

Keil Micro Vision is an integrated development environment used to create software to be run on embedded systems. It allows for such software to be written either in assembly or C programming languages and for that software to be simulated on a computer before being loaded onto the microcontroller.

The software used in C programming Keil μ-Vision3.0 is an IDE (Integrated Development Environment) that helps to write, compile and debug embedded programs.

It encapsulates the following components:

• A project manager

• A make facility

• Tool configuration

• Editor

• A powerful debugger PRO51 BURNER SOFTWARE:

PRO51 BURNER provides software burning tools for 8051 microcontroller in their flash memory. Through PRO51 BURNER tools, you can burn AT89C/SXXXX series of ATMEL microcontrollers.

V. A BREIF INTRODUCTION TO MICRO- CONTROLLER:

A microcontroller is a single chip that contains the processor (the CPU), non-volatile memory for the program (ROM or Flash), volatile memory for input and output (RAM), a clock and an I/O control unit.

AT89S52 MICROCONTROLLER:

The AT89S52 is a low power, high performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable flash memory. The device is manufactured using Atmel‟s high-density non-volatile

memory technology and is compatible with the industry- standard 80C51 instruction set and pin out. The on-chip flash allows the program memory to be reprogrammed in-system or by a conventional non-volatile memory programmer. by combining an 8-bit CPU with in-system programmable flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller which provides a highly flexible and cost effective solution to many embedded control application. The AT89S52 provides the following standard features, 8k bytes of flash, 256 bytes of RAM, 32 I/O lines, 2 data pointers, three 16 bits timer/counter, a six-vectors two-level interrupt architecture, a full duplex serial port 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.

The additional feature of AT89S52 makes it a powerful microcontroller for applications that requires pulse width modulation, high speed I/O and up/down counting capabilities such as motor control.

The pin diagram of 8051 shows all of the I/O pins unique to microcontroller.

Fig.2 : Pin Diagram of 8051 Microcontroller

(3)

88 The 8051 architecture consists of these specific features:

• 16 bit PC and data pointer (DPTR)

• 8 bit program status word (PSW)

• 8 bit stag pointer (SP)

• Internal ROM of 4k bytes

• Internal RAM of 128 bytes

• 4 registers banks, each containing 8 registers

• 80 bits of general purpose data memory

• 32 I/O pins arranged as four 8 bit ports: P0-P3

• Two 16 bit timer/counter:T0-T1

• Two external and three internal interrupt sources oscillator and clock circuits.

VI. BRIEF INTRODUCTION OF AT COMMANDS AT commands are a set of commands that has been standardized to communicate with terminal equipments such as modem, mobile phone as well as control them.

Most GSM modems supports AT commands. The command set is quiet elaborate. However, only a small part of it is related to SMS operations. The most frequently used commands are:

• AT+CMGS - To send a short message

• AT+CMGR – To read a short message from the GSM module

• AT+CMGL – To list SMS short messages stored in the GSM module

• AT+CMGD – To delete a short message from the GSM module

• AT+CMGF – To convert the message into machine instruction format

• AT+CPMS – To select the SMS memory

• AT+CNMI – To remind mode set up when receive a new message.

As the low level function interface to the GSM modem, these commands play a fundamental role in the software developing of the gateway program.

VII. A BRIEF INTRODUCTION OF GSM SIM 300 MODEM

GSM/GPRS module is used to establish communication between a computer and a GSM-GPRS system. Global System for Mobile communication (GSM) is an architecture used for mobile communication in most of the countries. Global Packet Radio Service (GPRS) is an extension of GSM that

enables higher data transmission rate. GSM/GPRS module consists of a GSM/GPRS modem assembled together with power supply circuit and communication interfaces (like RS-232, USB, etc) for computer. The MODEM is the soul of such modules. SIM300 is a Tri- band GSM/GPRS engine that works on frequencies EGSM 900MHz, DCS 1800MHz and PCS 1900 MHz.

SIM300 provides GPRS multi-slot class 10 capability and supports the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4.

Following are the few technical details of the modem:

FEATURES:

Power supply-Single supply voltage 3.4-4.5V Power saving-Typical power consumption in SLEEP mode to 2.5mA

GSM class-Small MS

Transmit power- Class 4(2W) at EGSM 900 Class 1(1W) at DCS 1800 and PCS 1900

SMS- MT, MO, CB, Text and PDU mode SMS storage: SIM card

SIM interface-Supported SIM card: 1.8V, 3V External antenna-Connected via 50ohm antenna connector

Audio features- Half Rate (ETS 06.20) Full Rate (ETS 06.10)

Enhanced Full Rate (ETS 06.50 / 06.60/ 06.80)

Echo suppression

SIM application toolkit-Supports SAT class3, GSM 11.14 Release 98

Real time clock-Implemented

Timer function-Programmable via AT command VIII. WORKING

In this project, we are using the GSM technology.

A micro controller is a small computer on a single integrated circuit consisting of a relatively simple CPU combined with support functions such as timers etc.

Microcontrollers are used in automatically controlled products and devices such as remote controls, office machines, power tools and toys. The LCD displays the current operation of the system. The microcontroller is used to control the relay drivers depending upon the

(4)

89 software program. Major role of this project is to receive the SMS to speed control of stepper motor.

Initially, the SMS is received from the person authorized to use this set up by the GSM modem (SIM300 MODEM) and is transferred to the microcontroller devices kit with the help of a MAX232 chip. As per the AT commands given by the microcontroller to the modem, the control signal is extracted and is used to control the devices connected to it. We have to convert the „septets‟ of the phone to

„octets‟ because the microcontroller needs bytes with 8 bits length. All this process is necessary to decode the message from SMS. A program is loaded into microcontroller devices kit and then the circuit is connected to the modem. The microcontroller now tries to read the SMS from the first memory location of the modem and keeps trying again until the modem receives any (programmed for every one second). Before implementing the control signal part of the SMS, the modem extracts the number from the SMS and verifies if this number has the access to control the device or not. For controlling the devices, the message will be sent in hexadecimal format. The hex data is converted into binary and the particular output is enabled. We have connected LEDs to the ports of microcontroller to show the output and their status indicates whether the ports are set to „ON‟ or „OFF‟. And speed control like send the message in text format like MOTOR SPEED LOW, MOTOR SPEED MEDIUM and MOTOR SPEED HIGH for stepper motor.

IX. STEPPER MOTOR

A stepper motor (or step motor) is a brushless, synchronous electric motor that can divide a full rotation into a large number of steps. The motor‟s position can be controlled precisely, without any feedback mechanism. Stepper motors are similar to switched reluctance motors (which are very large stepping motors with a reduced pole count, and generally are closed-loop commutated).

FUNDAMENTAL OF OPERATION:

Stepper motors operate differently from DC brush motors, which rotate when voltage is applied to their terminals. Stepper motors, on the other hand, effectively have multiple „toothed‟ electromagnets arranged around a central gear-shaped piece of iron. An external control circuit, such as microcontroller, energizes the electromagnets. To make the motor shaft turn, first one electromagnet is given power, which makes the gear‟s teeth magnetically attracted to the electromagnet‟s teeth.

When the gear‟s teeth are thus aligned to the first electromagnet, they are slightly offset from the next electromagnet. So when the next electromagnet is turned

on and the first is turned off, the gear rotates slightly to align with the next one, and from there the process is repeated. Each of those slight rotations is called a step, with an integer number of steps making a full rotation.

In motor can be turned by a precise angle.

• Stepper motors are constant power devices.

• As motor speed increases, torque decreases.

• Stepper motors exhibit more vibration than other motor types, as the discrete step tends to snap the rotor from one position to another.

• This vibration can become very bad at some speeds and can cause the motor to lose torque.

• The effect can be mitigated by accelerating quickly through the problem speeds range, physically damping the system or using micro-stepping driver.

• Motors with a greater number of phases exhibit smoother operation than those with fewer phases.

X. CONCLUSION

In the paper low cost, secure, ubiquitously accessible, auto-configurable, remotely controlled solution for automation of different motors has been introduced. The approach discussed in this paper has been achieved the target to control industrial appliances remotely using the GSM-based system satisfying user needs and requirements.

GSM technology capable solution has proved to be controlled remotely, provide industrial security has achieved the target to control different industrial appliances remotely using the SMS-based system satisfying user needs and requirements GSM technology capable solution has proved to be controlled remotely, provide industrial security and is cost effective as compared to the previously existing systems.

XI. ACKNOWLEDGEMENT

We would like to thank Mr. Amit Kumar and Miss Divya Arora Assistant Professor, COER for the opportunity to work with them, and also for their encouragement, trust and untiring support.

We are also thankful to Mr. A.S.Yadav, HOD Electrical Deptt. COER for their continuous inspiration during this project work. We thank and owe our deepest regards to all who have helped us directly or indirectly.

XII. REFERENCES:

[1] J.Wu and A.H.Aghvami, \A new adaptive equalizer with channel estimator for mobile radio

(5)

90 communications, ”IEEE transactions on Vehicular technology.

[2] http://www.engineersgarage.com/c-language- programs.

[3] http://electronicsforu.com/

newelectronics/microcontroller/default.asp.

[4] “The 8051 microcontroller and embedded system” using assembly and C. By Muhammad Ali Mazidi, Janice Gillispie Mazidi, Robin D.

Mckinlay.

[5] http://www.camiresearch.com/

Data_com_basics/RS232.

[6] http://www.gsm-modem.de/sms-text-mode.html.

[7] http://www.nationalsemiconductors.com.

