This document summarizes an assembly project demo of a stepper motor control circuit. It includes sections on the circuit diagram, schematic, layout, board fabrication process, operating modes, features, and problems faced with solutions. The circuit uses coils to create a magnetic field that interacts with permanent magnets in the motor shaft to rotate the shaft in sequences, allowing control of motor direction and speed.

1. ASSEMBLY PROJECT DEMO

3. Review
 Introduction
 Scope
 Circuit Diagram
 Schematic
 Layout
 Board File
 PCBA
 Operating Modes & Features
 Problems Faced & Solutions

4. Introduction
 A stepper motor's shaft has permanent
magnets attached to it. Around the body of
the motor is a series of coils that create a
magnetic field that interacts with the
permanent magnets. When these coils are
turned on and off the magnetic field causes
the rotor to move. As the coils are turned on
and off in sequence called ‘phase pattern’
the motor will rotate forward or reverse.

5. Scope
 High Speed Pick and Place Equipment
 Multi axis CNC machines
 Floppy disk drives
 Computer printers
 Plotters
 Optical scanners
 Conveyers
 Positioning Systems

6. CIRCUIT DIAGRAM

7. LAYOUT

8. BOARD FILE

9. PCB ASSEMBLY
 PCB assembly was carried out at SPOT
industries.
 Process
 Printing
 Pick and Place (SMTs)
 Manual Placement (SMTs)
 Reflow Soldering (SMTs)
 Placement (THTs)
 Manual Soldering (THTs)

10. Operating Modes
 We can control the operation mode of the
motor using SPDT. The operating modes
are:
 Manual Control
 Computer Controlled

11. Features
 Direction Control
 With appropriate combination of switches we can
control the direction of Stepper Motor in both
clockwise and anticlockwise direction.
 Speed Control
 Speed of the motor can be varied by changing the
resistance control knob of the variable resistor.

12. Problems Faced
 Bridging of IC pins during Reflow due to
greater pad width in Layout footprint.
 Mismatching of Schematic and Layout
footprint pin number.
 Variable Resistor
 SPDT

13. Solution
 Manual detachment of IC pin.
 Removed the faulted tracks and added
jumpers manually.