Interfacing Stepper Motor with PIC Microcontroller

Introduction

A Stepper Motor is a brushless, synchronous DC electric motor, which divides the full rotation into a numberΒ of equal steps. It finds great application in field of microcontrollers such as robotics. Please refer the article Stepper Motor or Step MotorΒ for detailed information about working of stepper motor, types and modes of operation. Unipolar Motor is the most popular stepper motor among electronicsΒ hobbyist because of its ease of operation and availability. Here I explaining the working ofΒ Unipolar and Bipolar Stepper Motor with PIC 16F877A Microcontroller.Stepper- Interfacing Stepper Motor with PIC Microcontroller

Microcontroller by using readymade ICs such as L293D orΒ ULN2003. As I said in the article Stepper Motor or Step Motor, we have three different types of stepping modes for unipolar stepper motor.

Note: 1 – Represents Supply Voltage andΒ 0 – Represents Ground

Wave Drive

In this mode only one stator electromagnet is energised at a time. It has the same number of steps as the full step drive but theΒ torque is significantly less. It is rarely used. It can be used where powerΒ consumptionΒ is more important than torque.

Driving Bipolar Motor

Bipolar motors are simpler in construction as it contains two coil and no centre tap. Being simple, driving is little complex compared to unipolar motors. To reverse the magnetic polarity of stator windings, current through it must be reversed. For this we should use H-Bridge. Here I using L293d, H-Bridge Motor Driver for that.Β We canΒ distinguish bipolar motors from unipolar motors by measuring the coil resistance. In bipolar motors we can find two wires with equal Β resistance.

Interfacing Unipolar Stepper Motor with PIC Microcontroller

L293D and L293Β are dual H-bridge motor drivers.Β The L293D can provideΒ bidirectional drive currents of up toΒ 600-mA at voltages from 4.5 V to 36 V while L293 can provideΒ up to 1A at same voltages.Β BothΒ ICs are designed to drive inductive loads suchΒ as dc motors, bipolar steppingΒ motors, relays and solenoids as well as other high-current or high-voltageΒ loads in positive-supply applications. All inputs of these ICs are TTL compatible and output clamp diodes for inductive transientΒ suppression are also providedΒ internally. These diodes protect our circuit from the Back EMF of DC Motor. In both ICs drivers are enabled in pairs, with drivers 1 and 2 are enabled by a high input to 1,2EN andΒ drivers 3 and 4 are enabled by a high input to 3,4EN. When drivers are enabled, theirΒ outputs will be active and in phase with their inputs. When drivers are disabled,Β their outputs will be off and will be in the high-impedance state.

ULN2003 is a monolithic high current and high voltageΒ Darlington transistor arrays.Β ULN2003 consists of seven NPNΒ Darlington TransistorΒ pairs that have high-voltage outputs with common-cathodeΒ clamp diode for switching inductive loads. The collector-currentΒ rating of a single darlington pair can beΒ up toΒ 500mA. We can connectΒ DarlingtonΒ Transistor pairs in parallel ifΒ higher current capability is needed..

Interfacing using L293DSchematic Interfacing Stepper Motor with PIC Microcontroller

For more detail: Interfacing Stepper Motor with PIC Microcontroller


About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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