This document provides an introduction to different types of motors and motor controllers that are commonly used in embedded systems, including stepper motors, servo motors, and DC motors. It describes how each type of motor works and how they can be connected and controlled using an Arduino or Raspberry Pi. Stepper motors move in discrete steps by energizing coils in sequence. Servo motors control angular position. DC motors have variable speed and direction controlled by voltage polarity and magnitude. Motor drivers can control multiple motors and be stacked together using I2C addresses. PWM signals can also control servo position and motor speed.

1. Introduction to Motors
and Motor Controllers
Programming for
Embedded Systems
MAHDI BABAEI
MBABAEI@DEAKIN.EDU.AU

2. Intro
 Motors are usable in:

3. Popular motor types for
embedded systems
 Stepper Motors
 Servo Motors
 DC Motors

4. Stepper
Motors

5. How do they work?
• Stepper motors are DC motors
that move in discrete steps.
• They have multiple coils that are
organized in groups called
"phases".
• By energizing each phase in
sequence, the motor will rotate,
one step at a time.

6. Stepper Motors
connection
 On Arduino  On Pi
stepper1 is made up of the M1 and M2 terminals, and stepper2 is made up of
the M3 and M4 terminals.

7. How to drive it?
 To drive a stepper we need to know 3 elements:
1. Number of steps: how many steps we want
2. Direction of Steps: Forward/Backward
3. Steps’ Style:
1. "Single" means single-coil activation
2. "Double" means 2 coils are activated at once (for higher torque)
3. "Interleave" means that it alternates between single and double to
get twice the resolution (but of course its half the speed).
4. "Microstepping" is a method where the coils are PWM'd to create
smooth motion between steps.

8. Run a stepper
 Direction: which should be one of the following constant values:
• stepper.FORWARD (default)
• stepper.BACKWARD
 Style: which should be one of the values:
• stepper.SINGLE (default) for a full step rotation to a position where one
single coil is powered
• stepper.DOUBLE for a full step rotation to position where two coils
are powered providing more torque
• stepper.INTERLEAVED for a half step rotation interleaving single and
double coil positions and torque
• stepper.MICROSTEP for a microstep rotation to a position where two
coils are partially active.

9. Run a stepper
 Pi:
from adafruit_motorkit import MotorKit
kit = MotorKit()
kit.stepper1.onestep(direction=stepper.BACKWARD, style=stepper.DOUBLE)
OR
for i in range(200):
kit.stepper1.onestep(style=stepper.MICROSTEP)
 Photon:
#include <Adafruit_MotorShield.h>
Adafruit_MotorShield AFMS = Adafruit_MotorShield();
AFMS.begin();
// Connect a stepper motor with 200 steps per revolution (1.8 degree)
Adafruit_StepperMotor *myStepper = AFMS.getStepper(200, 2);
myStepper->setSpeed(10);
for (i=0; i<255; i++) {
myStepper->step(1, FORWARD, INTERLEAVE); }

10. Servo Motors
 Servos deal with angle  Servo’s connection

11. Run a Servo
 Pi:
import RPi.GPIO as GPIO
import time
servoPIN = 17
GPIO.setmode(GPIO.BCM)
GPIO.setup(servoPIN, GPIO.OUT)
p = GPIO.PWM(servoPIN, 50) # GPIO 17 for
PWM
p.start(2.5) # Initialization
try:
p.ChangeDutyCycle(5)
time.sleep(0.5)
 Photon:
(There is no need to include Servo.h)
Servo myservo;
myservo.attach(3); //digital pin
myservo.write(90); //set servo to 90

12. DC Motors
Attributes:
1- Speed
2- Direction

13. DC motor connection

14. Drive a DC motor
 The four motor spots on the Shield are available as motor1,
motor2, motor3, and motor4.
 To move a motor you can set the throttle attribute.
 Speed:
Full Speed: throttle = 1.0 OR -1.0
Stop: throttle = 0.0
Half Speed: throttle = 0.5

15. Run a DC motor
 On Pi:
import time
from adafruit_motorkit import
MotorKit
kit = MotorKit()
kit.motor1.throttle = 1.0
time.sleep(0.5)
kit.motor1.throttle = 0
 On Photon:
#include <Wire.h>
#include <Adafruit_MotorShield.h>
Adafruit_MotorShield AFMS = Adafruit_MotorShield();
Adafruit_DCMotor *myMotor = AFMS.getMotor(1);
AFMS.begin();
myMotor->setSpeed(150);
myMotor->run(FORWARD);

16. Motor Driver

17. Stackable drivers and driving
multiple motors

18. I2C Addresses for drivers
stack
Board 0: Address = 0x60 Offset
= binary 0000 (no jumpers
required)
Board 1: Address = 0x61 Offset
= binary 0001 (bridge A0)
Board 2: Address = 0x62 Offset
= binary 0010 (bridge A1, the
one above A0)
Board 3: Address = 0x63 Offset
= binary 0011 (bridge A0 & A1,
two bottom jumpers)
Board 4: Address = 0x64 Offset
= binary 0100 (bridge A2, middle
jumper)

19. Program the stack
 On Pi:
from adafruit_motorkit import MotorKit
kit1 = MotorKit()
kit2 = MotorKit(address=0x61)
 On Photon:
#include <Adafruit-MotorShield-V2.h>
Adafruit_MotorShield AF = Adafruit_MotorShield();
Adafruit_MotorShield AF2 = Adafruit_MotorShield(0x61);

20. PWM and Multiplexer
 Adafruit 16-Channel 12-bit PWM/Servo Driver - I2C interface

21. Thank You

22. Q&A