The document discusses a microcontroller-based linear positioning system using a unipolar stepper motor. The system can move up and down along a floor and displays the opening and closing of positioning doors using LEDs. A microcontroller controls the stepper motor driver and positioning based on inputs from microswitches. Components include a stepper motor, driver circuit, microcontroller, LEDs, and switches. The system is programmed in C language to control the motor's movement between four positions.

2. PROCESSOR UNIT
 Microprocessor is widely used processer unit for
processing the large set of data and instruction given by
user.
It has only the CPU unit and require external
RAM, ROM, I/O and other peripheral.
 To perform the small set of specific
function, Microprocessor is a expensive and bulkier
cercuit.
 To overcome the problem, we use a low cost and
simpler circuit chip, called Microcontroller.
 Microcontroller is a mini computer on a single
integrated circuit chip containing a processor

3. MICROPROCESSER AND MICRO CONTROLLER

4.  Microcontroller 8051 has 4K ROM(code memory) and
128 byte RAM, two timer/counter, 4 general purpose
input/out port and interrupt control logic with 5 sourse.

5. PROJECT INTRODUCTION
 In the project a microcontroller based unipolar stepper
motor used to creat a four stroke linear positioning
system, this system can move up and down, along with
the floor.
 The opening and closing of this linear stroke
positioning doors are displayed on the green and red
LED’s respectively.
The positioning is controlled by four micro- switches.
 The control program is developed in “C” language and
converted into executable or in HEX language by AVR-GCC
compiler.

7. LIST OF COMPONENTS REQUIRED
 FULL WAVE BRIDGE RECTIFIER WITH 4 IN
4001DIODES, 220/12V TRANSFORMER(SINGLE PHASE)
AND 1000UF CAPACITOR.
 LM7805 VOLTAGE RAGULATOR.
 89C51 MICROCONTROLLER.
 UNIPOLAR STEPPER MOTOR.
 ULN2003 STEPPER MOTOR DRIVER.
 LCD(16*2)
 TWO ORDINARY LED’S (GREEN AND RED)

8. STEPPER MOTER
 Stepper moter is a microcontroler controlled DC moter
that can rotate in both direction and having a holding
torque at zero speed.
 Stepper motors are rated with a varying degree of
inductance.
A high inductance motor will provide a greater amount of
torque at low speeds and lower torque at high speeds.
 Stepper motor is designed to run hot between the ranges
of 50-90 degree.

9.  On the bases of wire arrangement stepper motor are
categorized into two types-
1. Unipolar stepper motor 2. Bipolar stepper
motor.
Center taps are present Center taps are not present
so have two winding/phase so Have single winding/phase
 Less efficient because of More efficient(50% more
50% utilization of wire. then unipolar)
Provide Low torque High torque & great power

10. Why we Prefer Unipolar Stepper Motor instead
of Bipolar Stepper Motor-
 In Bipolar Stepper Motor we require a H-bridge
complicated driver circuit to reverse the current direction in
winding, which is costely and motor efficiency decreases.
But Unipolar Stepper Motor has two windings per
phase, one for each direction of magnetic field, so in this
arrangement a magnetic pole can be reversed without
reverse the direction of current.
 Unipolar Stepper Motor can be control using bipolar
method by removing the connection of the common wires
but reverse is not possibal.

11. STEPPER MOTER WITH MICROCONTROLLER
 Stepper motors with microcontrollers are used in
numerous applications when there is need of controlling
the motion.
 The microcontroller is used to controls the speed as well
as position of stepper motor. The speed of stepper motor is
directly proportional to the frequency of drive input pluses
which is controllable with the help of microcontrollers and
the rotation is proportional to the number of output pulses.
 The speed of stepper motor is controlled by changing the
delay time of pulses and control over position is done by
the number of pulses.

12. STEPPER MOTOR DRIVER
 Microcontroller output pulse is not sufficient to drive the
stepper motor, stepper motor’s coil need arround 10mA to
energize but the microcontroller’s pin can provide a
maximum of 1-2mA current, so we use a driver cercuit to
operate the stepper motor.
 Driver cercuit is basically a current amplifier, that receive
low level signals from the controller and convert them into
electrical pulses to run the motor.
 TYPES OF STEPPER MOTOR DRIVER-
 R/L DRIVER
 BIPOLAR DRIVER
 UNIPOLAR DRIVER

13. RESISTANCE LIMITED DRIVER
 The drives are too old as compared to the driver’s
technology. They only exist in some application because
they are simple and inexpensive.
BIPOLAR DRIVER
These driver used in bipolar stepper motor for industrial
purpose applications. These drives are more expensive but
they offer high performance and efficiency.

14. UNIPOLAR DRIVER CERCUIT ( ULN2003A )
 It is used to drive unipolar stepper motor.
 Phase winding of motor have large inductance, therefore
in series in each phase winding a resistance is inserted to
reduce the circuit time constant. A resistance is also
placed in series with the diode in order to dissipate the
energy stored in the phase winding inductance.

16. FULL WAVE BRIDGE RECTIFIER
Full wave bridge rectifier is used to convert the ac supply
into dc supply.
For this purpose four IN 4001 general purpose diodes is
used in bridge configuration.
 An electrolytic capacitor of 1000 microfarad is
connected parallel with these diodes to filter-out the
harmonics present in the DC output supply.

17. LM7805 VOLTAGE REGULATOR
LM7805 voltage regulator is used to generating output
current of 1A and for changing 12V DC to 5DC.
It provides thermal overload protection and short circuit
protection to the connected device.
LM7805 have lower power consumption and provides
better voltage regulation to the connected system.

18. LIQUID CRYSTAL DISPLAY (LCD)
A LCD(liquid crystal display) is specifically menufactured
to be used with microcontroller, it cannot be activated by
standard IC cercuit.
It is used for displaying different massages on a liquid
crystal display.
It display all the letters of alphabet, mathematic
symbols, Greek letters etc. In addition, it is possible to
display symbols made up by the user.
Other usel features are automatic massage sift(left to
right) and cursor appearance.

20. PROJECT DISCRIPTION
The design project is divided into four step of equal
distance step.
The stepper motor is connected to the 4 stroke linear
lifting pulley with belt.
The stepper motor pulley will took 40full rotations to lift
the 4stroke linear positioning to cover the distance from
one step to another.
The LCD display the real time information about the 4
stroke linear positioning.
At desired location green LED glow which represent the
opening of 4 stroke linear positioning door and after five
sec delay green LED off and red LED glow which
represents the closing of 4 stroke linear positioning door.

22. Stepper motor covers 7.5 degree rotation in one step so
we fix 40 such full rotation that moves this motor to one
desired floor .
No. of steps are given by microcontroller to the stepper
motor driver.
For each floor position we have fixed a micro-switch.
When we press switch for first floor 40 rotations are
selected by controller and we reach to desired floor and if
we want to go to second floor we select second switch
which provide 80 full rotation of stepper motor and so on.