Speed Control of stepper Motor
Mr. Pramod Kumar
Electrical & Electronics
Ameer- Uz -Zama
• Stepper motors are used for precision
position control in many applications like
floppy drives, printers, process control
instruments, robotics and machine tool control.
• Here is a microcontroller AT89C51-based
stepper motor controller that can accurately
control the rotation direction, speed and
number of revolutions with help of six tactile
Hex converter (7404) IC:
• 7404 is a NOT GATE IC.
• It consists of six inverters (NOT gates).
• The output of an inverter is the complement of its
input logic state
LM7805 Voltage Regulator IC:
• It is a three Terminal voltage regulator IC.
• Gives a constant 5v output voltage.
• Output Current up to 1A.
• Short circuit protection.
• Output voltages 5, 6, 8, 9, 10, 12 ,15, 18, 24V.
• It is an electronic oscillator that creates an electric
signal with very high frequency.
• Provides a stable clock signal to the MCU.
• Max. 16 MHz can be used with the MCU.
• Brushless Digitally controlled motor
• Input is give in the form of electrical pulses.
• Converts Electric pulses into specific rotational
• Divides a full rotation into a large no of steps.
• Rotation in both directions.
STEP : For every input pulse the motor shaft
turns through a specified number of degree
called a step.
• Depending on the motor, this step angle may
be as small as 1 (or less) or as large as 45.
The stepper motor used in the project has following
• Step Resolutions: 18 degrees per pulse.
• Max revolutions per minute: 1000
Types of Stepper Motor
• Magnetic rotor
• Non Magnetic , Geared Rotor.
• Combines characteristics from PM and VR Stepper
• Magnetic , Geared Rotor.
Types of Permanent Magnet Stepper
Wave Drive: Only one coil is energised in a rotatory
• The bit pattern is 0001,
0010, 0100, 1000.
• In this example, step angle
is 90 degrees.
Full step drive :
• Two adjacent coils are energized successively in a
• The bit pattern will be 0011,0110,1100,1000,1001 ,
Half Step Drive :
• The stepper motor operates at half the given steeper
• The bit pattern is
Unipolar and Bipolar Stepper Motor
Bipolar Stepper Motor:
• Bipolar uses entire winding at a time.
• There is no centre tapping.
• Bidirectional current flow through each winding.
• Four wire bipolar motor.
Unipolar Stepper Motor:
• There is a centre tap added between the two leads.
• Unidirectional current flow in each half of the
• Special purpose computers.
• Dedicated to one task ( i.e no Multitasking).
• Low power device.
• Operates on 5v dc.
• In our project we are using AT89C51
• 4k bytes of Programmable and erasable Read Only
• Power consumption of 50 mW.
• Manufactured by ATMEL and belongs to 8051
• 40 pin DIP package.
• Four I/P bidirectional ports.
• Two 16 bit timers/counters.
Motor : Stepper Motor
• Type : Bipolar Stepper motor.
• Step Angle : 18 degrees.
• Step Sequence: Half step Drive.
Parameters of Stepper Motor to be
• No. of Rotations
•We have simulated our project on
Proteus 8 Professional software.
•The project underlines the complete
controlling of Stepper Motor.
• We can connect our project to the serial port of
computer and can control the speed of it using
• It follows synchronous data link standard.
• Serial communication is the process of sending
data one bit at a time.
Difference Between Stepper Motor and
• It is a Digital
• Input is in the form of
• The shaft moves through
• It is an electromechanical
• Input is given from a
constant voltage source.
• It has a free Running Shaft.
Industrial Applications Of Stepper
• Floppy Disk Drives.
• Hard Disk Drives.
• Printers, Plotters.
• Electronic Watches.
• Electronic Typewriters.
• Teleprinter, Telex-machines.
• Instrumentation control.
• The project can be used perfectly in many
• The device is easy to implement in hardware
and software means.
• The circuit is cost effective , consume less
power and take minimum time.