Stepper Motor: 28BYJ-48

stepper motor controller uln2003 s

The 28BYJ-48 is a 5 Volt heared stepper motor. The detailed specs of the 28BYJ-48 stepper motor as shown as belows:

Motor Type Unipolar stepper motor
Connection Type 5 wire connection (to the motor controller): Blue, Pink, Yellow, Orange, Red
Voltage 5 Volts DC
Number of Phase 4
Operating Frequency (PPS) 100Hz
Step Mode Half-Step Mode : 8 step control signal sequence (recommended)
Full-Step Mode: 4 step control signal sequence
Step Angle Half-Step Mode: 5.625º per step / 64 steps per one revolution of the internal motor shaft.
Full-Step Mode: 11.25º per step / 32 steps per one revolution of the internal motor shaft
Gear ratio Manufacturer specifies: 64:1
Experimental result: 63.68395:1
Full revolution = steps per motor rotation x gear ratio
For half-step: 64 step per motor rotation x 63.68395 gear ratio ≒ 4076 steps per full revolution
Step Angle (1-2 phase) 5.625º / 64

Step Sequence

The 28BYJ-48 is an Unipolar Stepper Motor. It has 4 coils of wire that are powered in a sequence to make the magnetic motor shaft spin. When using the full-step method, 2 of the 4 coils are powered at each step. For the half-step mode, the first step is to power coil 1,  then coil 1 and 2 together, then coil 2 only, and so on.. With 4 ciols, the half-step mode has 8 different signals. The following tabls show the steps for half- and full-step mode.

WAVE DRIVE: 1-Phase at a Time

  A
IN4
B
IN3
C
IN2
D
IN1
Step 1 X      
Step 2   X    
Step 3     X  
Step 4       X

Simplest, but least used.

HALF STEP: 1 or 2 Phase at a Time

  A
IN4
B
IN3
C
IN2
D
IN1
Step 1 X      
Step 2 X X    
Step 3   X    
Step 4   X X  
Step 5     X  
Step 6     X X
Step 7       X
Step 8 X     X

Smallest step angle. Medium torque.

FULL STEP: 2 Phases at a Time

  A
IN4
B
IN3
C
IN2
D
IN1
Step 1 X X    
Step 2   X X  
Step 3     X X
Step 4 X     X

Strongest torque.