Abstract:
A stepper motor is an electromechanical device, which converts electrical pulses into discrete mechanical movements. The shaft or spindle of a stepper motor rotates in discrete step increments when electrical command pulses are applied to it in the proper sequence. The motors rotation has several direct relationships to these applied input pulses. The sequence of the applied pulses is directly related to the direction of motor shafts rotation. The speed of the motor shafts rotation is directly related to the frequency of the input pulses and the length of rotation is directly related to the number of input pulses applied.

We can use the stepper motor to control the motion of a robot but the biggest hurdle is the wired control. We can control the stepper motor wirelessly through RF link. In this project we are controlling the stepper motor wirelessly through RF link. We are using RF module and AT89S52 microcontroller to achieve this motive.

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Objective:
A stepper motor is an electromechanical device, which converts electrical pulses into discrete mechanical movements. The shaft or spindle of a stepper motor rotates in discrete step increments when electrical command pulses are applied to it in the proper sequence. The motors rotation has several direct relationships to these applied input pulses. The sequence of the applied pulses is directly related to the direction of motor shafts rotation. The speed of the motor shafts rotation is directly related to the frequency of the input pulses and the length of rotation is directly related to the number of input pulses applied.
We can use the stepper motor to control the motion of a robot but the biggest hurdle is the wired control. We can control the stepper motor wirelessly through RF link. In this project we are controlling the stepper motor wirelessly through RF link. We are using RF module and AT89S52 microcontroller to achieve this motive.
Following are the main components of this project:
1) RF Module
2) Microcontroller.
3) Output mechanical transducer (stepper motor).
RF MODULE
ASK Super Regenerative Receiver
ST-RX02-ASK Receiver
General Description:
The ST-RX02-ASK is an ASK Hybrid receiver module.
A effective low cost solution for using at 315/433.92 MHZ.
The circuit shape of ST-RX02-ASK is L/C.
Receiver Frequency: 315 / 433.92 MHZ
Typical sensitivity: -105dBm
Supply Current: 3.5mA
IF Frequency:1MHz
Features
• Range in open space(Standard Conditions) : 100 Meters
• RX Receiver Frequency : 433 MHz
• RX Typical Sensitivity : 105 Dbm
• RX Supply Current : 3.5 mA
• RX IF Frequency : 1MHz
• Low Power Consumption
• Easy For Application
• RX Operating Voltage : 5V
• TX Frequency Range : 433.92 MHz
• TX Supply Voltage : 3V ~ 6V
• TX Out Put Power : 4 ~ 12 Dbm
Applications
• Remote Controls
• Automation System
• Wireless Security System
• Sensor Reporting
• Car Security System
• Remote Keyless Entry
A BRIEF INTRODUCTION TO 8051 MICROCONTROLLER:
When we have to learn about a new computer we have to familiarize about the machine capability we are using, and we can do it by studying the internal hardware design (devices architecture), and also to know about the size, number and the size of the registers.
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. Also called a "computer on a chip," billions of microcontroller units (MCUs) are embedded each year in a myriad of products from toys to appliances to automobiles. For example, a single vehicle can use 70 or more microcontrollers. The following picture describes a general block diagram of microcontroller.
AT89S52: 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 nonvolatile memory technology and is compatible with the industry-standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory pro-grammer. By combining a versatile 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 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, a six-vector two-level interrupt architecture, a 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 con-tents but freezes the oscillator, disabling all other chip functions until the next interrupt