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Arduino & Servo

Arduino & Servo: Moving an Arm

June 14, 2024

Source: <Arduino & Servo: Moving An Arm or Throwing A Ball - STEAM Clown>

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Teachers: Before You Present

Update the Canvas Links, or Delete the bullets linking to Canvas links (Typically Labs)

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www.STEAMClown.org

Science

Technology

Engineering

Art

Math

Click on "STEAM Clown's Taipei Workshops"

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Licensing & Attribution

Open Source Philosophy - I have come to realize that I’m really not competing with other teachers. Maybe I have some local competition, but in reality, if a student is not coming to my class or my school, then I’m not competing with other teachers in any way… If you work more than a District away, then we really are not competitors. Let's Share... Collaborate... Help each other... I, and you, may have sweat blood and tears developing a lesson plan, a lab, or presentation… There is an ENORMOUS unpaid value there… I get that… I don’t begrudge teachers who are trying to sell their collateral… I’m just saying that is not what I’m going to do. But that is my plan. I’m going to share virtually everything I develop. Join Me!!! See More

CC BY-NC-SA 4.0

https://creativecommons.org/licenses/by-nc-sa/4.0/

https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode

GNU Public License & EUPL (European Union Public Licence)

Any included or linked Programming Code Is licensed under GNU General Public License v3.0 & and / or licensed under EUPL 1.2 or later

See the Appendix for Additional Licensing & Attribution Information

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Please maintain this slide with any modifications you make:

This content is licensed as Open Source / Creative Commons: A Specific use license has been provided to any organizations listed in the Appendix

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Objective, Overview, & Introduction

Move A Robot Arm With A Servo?

You will, as a team, build an Arm Waving Robot
You will incorporate Design Thinking during your Kinetic Machine planning phase

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What You Will Know...

Prior Knowledge & Certifications

You should have some working practice with a Microcontroller (Arduino) interfacing to the "Real World"

What You Will Know & Be Able To Do

You will be able to clearly explain the design process to use a Servo and Microcontroller
You will be able to create a block diagram of your Kinetic Machine incorporating sensors, a Microcontroller, Servo in your Kinetic system
Work as a Team

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How You Will Be Measured

Show examples of Design Planning Drawings
Show Your Servo Waving an Arm, and Controlling it from an Arduino, with Code you designed, edited, and deployed

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Essential Questions

How can inputs from the "Real World" be processed in a program, and then used to affect the "Real World" in a meaningful way?
How can you apply Design Thinking and Creative Engineering to making something move?

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Resources & Materials Needed

PC, Laptop or Other device to access sites & applications specified by your Instructor
A Microcontroller (an Arduino is used in this presentation)
Switches, Sensors, Motors, Servos and other electronic components
Makey Bot kit, or Crazy and Creative use of material like Duct Tape, Legos, Hot Glue, Cardboard, Pipe Cleaners, and other stuff to add "Bling" to your Arm Waving Robot…

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New Words or Concepts...

Servo
Kinetic Machine
Microcontroller
Sensors (inputs)
Servos & Motors (Kinetic Outputs)

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Workshop Introduction

Connecting Hardware & Code To The Outside World… But First In A Simulator, Then IRL

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Are you ready to take your learning into the future?

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👉 Try This:

This is a Hands On Project. Try Stuff!!!!

Browser: You can use a web based Browser TinkerCAD. (SignUp Workshop Presentation)
Please take the time to build the example in TinkerCAD or on a real Breadboard.

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print("Hisssssssssss")

Try This 👉

Try This

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TinkerCAD Account Setup

Connecting Hardware & Code In A Simulator

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Are you ready to take your learning into the future?

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TinkerCAD - Join NOW

https://www.tinkercad.com/

Click JOIN NOW or Sign In

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(TinkerCAD SignUp Workshop Presentation)

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TinkerCAD Introduction

Connecting Hardware & Code In A Simulator

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Are you ready to take your learning into the future?

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TinkerCAD - Learn About Electronic Circuits

https://www.tinkercad.com/

Click JOIN NOW or Sign In

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(TinkerCAD Simulation Workshop Presentation)

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Arduino Introduction

Connecting Hardware & Code To The Outside World

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Are you ready to take your learning into the future?

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Did You Say “Arduino”?

Arduino Is An Open-source Electronics Platform

With easy to use hardware & software.
Intended for making interactive projects

Arduino Can Sense & Control It’s Environment

Receiving information on input pins
Affecting its surroundings by controlling lights, motors, actuators, etc on output pins

You Tell Your Arduino What To Do

Writing code in the C++ coding language using the Arduino development environment

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Go From a Sketch to Blinking an LED

Compiler�& Linker

1011001010

0110101101

1110100100

1010101100

0101100110

1011001010

1000100101

0101101001

1110101100

0011100110

1111001010

1100101101

1010110100

1110101100

1111100110

0011001010

1101111110

1010110100

1110101100

1001100110

Bootloader

1101001011

1110001001

1011101100

1110011101

1101110101

Arduino

Library

Files

Executable

Source Code

Host Computer

CPU

Ports

Blinking LED

USB

Download

Cable

Flash Program Memory

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What Are We Going To Do?

Teams of Two
Kinetic Events and Contraptions
Microcontroller (Arduino) Code
Inputs - Switches and Sensors
Outputs - Electro-Mechanical (Servos & Motors)

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Switch (Input) → Arduino → LED (Output)

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LAB #1�Review Of Arduino and Blinking LED

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Arduino Uno Controlling the World… or just an LED

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Link: TinkerCAD Rube-Goldberg Blink LED

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Click "Tinker This" To Make Your Own Copy

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Link: TinkerCAD Rube-Goldberg Blink LED

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Click on "CODE"

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Lab#1 - Blink An LED

Run this code

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// This is where you define pin directions

int LED = 13;

// The setup routine runs once when you load a sketch or press reset:

void setup()

{

// initialize the pins used in this sketch

pinMode(LED, OUTPUT); // LED where you assigned it on pin 13

}

// this "main" loop routine runs over and over again forever:

void loop()

{

//Set pin 13 to HIGH. This provides 5v to the LED & turns it on

digitalWrite(LED, HIGH);

delay(1000); //Wait for a second

//Set pin 13 LOW and This turns the LED off

digitalWrite(LED, LOW);

delay(1000); //Wait for a second

}

https://raw.githubusercontent.com/jimTheSTEAMClown/Rube-Goldberg/main/blink

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Lab#2 - Move LED Pin To Something Other Than Pin 13

Move your LED Output from pin 13 to Pin 2
Update your code

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int LED = 2;

Pro Tip: Don't use pins 0 or 1. Why?

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LAB#3 - Add A Switch to Your Arduino and Blinking LED

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Lab#3

Connect A Switch & Read It's State

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Lab #3 - Read A Switch Value

To find out if a button is being pushed, what do we need to do?

We need to assign a pin as an input��

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int sensor_pin = 7; //assign button to pin 7

pinMode(sensor_pin, INPUT);

Pin 7 is now an Input

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Where Do We Connect The Switch Input?

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Lab #4 - Now that we know the pin the sensor is assigned, how do we store the value?

We need a variable to hold the button_state��

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int sensor_state = 0;

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Lab #4 - How do we actually tell the Arduino to read an Input pin?

We need to invoke the digitalRead() function��

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// Reads the Switch

sensor_state = digitalRead(sensor_pin);

Serial.print(sensor_state);

What else do we need to add to our code to be able to print to the consol?

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Lab #4 - Setup a Arduino Sketch to be able to print?

We need to add the Serial.begin(9600); method to the setup() function��

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// Enables Serial.print

Serial.begin(9600);

Serial.println(sensor_state);

Maybe add a delay(200); to make the print of the sensor_state slow down so you can see it…

Add this line when you want to print something

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Lab: Switch, Read It, Save It, Do Something…

Finish the lab where you have done the following:

Connected a Breadboard LED to Pin 2, and can flash it
Connected a Button (Pulled Down) to Pin 7, and can read it
Print the value of the Button to the Arduino IDE Console
Turn on the LED when the Button is pushed

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Turn on the LED when the Button is pushed

OK, Our LED is blinking on and off? Why?

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void loop()

{

digitalWrite(LED, HIGH);

delay(1000);

digitalWrite(LED, LOW);

delay(1000);

}

digitalWrite(LED,sensor_state);

In the digitalWrite() what can �we change to send the value of the switch?

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Switch (Input) → Arduino → LED (Output)

Show diagram of Sensor (Input) → Arduino → Motor (Output)

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https://www.tinkercad.com/things/3YNgZnUgwXZ

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Dig Deeper

Extra Credit Labs

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Write code that uses an IF statement to check the sensor_state value and then do something based on that.

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Sensor (Input) → Arduino

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Arduino → Electro-Mechanical Device (Output)

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Servo Motor Introduction

Moving Things With Arduino C++ Programs

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Servo Motor Introduction

A servomotor is a rotary actuator or linear actuator that allows for precise control of angular or linear position
This means, it is a motor that we can precisely control the position.
Servo motors are found in the motor unit of industrial, robotic, manufacturing appliances.

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Two Types of Servos

180° Servos - The most common Servo that will turn 180°

They will turn from 0° to 180° degrees
In many cases they can't actually get to 180° and will stop at something less, like 172°

Continuous Rotation Servos - These will turn continuously clockwise or counterclockwise for 360°

Many times you will find these on Robot drive systems

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They Look The Same...

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Servo Horns - Moving Stuff

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Servo Horn Connection �Examples

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Pulse Width Modulation

PWM

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Averaging The "ON" Time

Remember the LED and Potentiometer Lab?

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Servo Motors Explained

Lets Watch a Servo Motor Video(6 min)

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A servomotor is a closed-loop �servomechanism that uses position feedback to control its motion and final position
This means, it compares the current position to the target position and then has the motor turn to go the target position

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How a differential comparator works

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=

+

R₃

R₃ ≠ R₄so, V₃ ≠ V₄

R₂

R₄

R₁

R₁ = R₂so, V₁ = V₂

If V_in changes up or

down so does V₁ and V₂

V₁

V₂

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The PWM ON/OFF Time is Avaged to a Voltage

The Pulse Cycles is 20ms

The 0° position Pules = 1ms, which is 5% of 20ms or 5% of the max voltage
The 90° position Pules = 1.5ms, which is 7.5% of 20ms or 7.5% of the max voltage
The 180° position Pules = 2ms, which is 10% of 20ms or 10% of the max voltage

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V_{Motor POS}

V_PWM

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Actual PWM Voltage Comparator

A servomotor is a closed-loop servomechanism that uses position feedback to control its motion and final position
This means, it compares the current position to the target position and them have the motor turn to go there

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Let's Move Stuff...

PWM and Servo Labs

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Arduino Servo PWM Code

Import these Libraries. Add these lines of code to the top of your program. The Servo.h library keeps track of all the PWM timing

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#include <Servo.h> // Import Servo Library

// create servo object to control a servo

// my_servo can be any name.

// Twelve servo objects can be on most Arduino boards

Servo my_servo;

int pos = 0; // variable to store the servo position

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Arduino Servo PWM Code

Setup the GPIO and Servo settings

my_servo.attach(9);is the library method to attach the servo to the Arduino pins. In this case it is attached pin 9, but all the digital pins can connect to servos.

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my_servo.attach(9); // Servo on pin 9 to servo object

pos = 0; // Set position Variable

my_servo.write(pos); // Set the default start position

delay(1000); // Delay just a bit to get into position

In void setup()

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Tell Your Servo Where To Start

A good practice when using Servos and other motors, is to tell them where to start. What is the default start position?
Before you tell the Servo to move as part of your main program, tell it where to start
Add this code just before you tell the Servo to actually do something. This way you know where you are starting.

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pos = 42; // Set position Variable

my_robot_servo.write(pos); // Set the start position

delay(1000);

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Telling The Servo What Position (Angle) To Go To

A Servo methods in the Servo.h library is my_servo.write(0)�

Remember the Duty Cycle…

The PWM Duty Cycle can be a number between 0 - 100
It represents the % "On" time of the Pulses in the Duty Cycle

The 0° position is 1ms, about 5% of 20ms
The 90° position 1.5ms, about 7.5% of 20ms
The 180° position is 2ms, about 10% of 20ms

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Arduino Servo PWM Code

my_servo is the variable name of your servo object and .write(n) is a servo library method
my_servo.write(0) tells the servo to move to position 0, by setting the minimum PWM width
my_servo.write(120) changes the PWM pulse width and moves to position 120

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my_servo.write(0);

delay(3000);

my_servo.write(120);

delay(3000);

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Lab Time

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Hookup the Servo circuit

Pin 5V (VCC) to the Red wire
Pin (GND) to �the Black or Brown wire
Pin 9 to the Orange (Signal) wire

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https://raw.githubusercontent.com/jimTheSTEAMClown/Rube-Goldberg/main/Servo_Move_Test.ino

https://www.tinkercad.com/things/i0U58ByC7kY

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Hookup the Servo circuit & Add Sensor or Button Input

Update Code to Mix the Sensor Code and the Servo Code

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https://raw.githubusercontent.com/jimTheSTEAMClown/Rube-Goldberg/main/Servo_Move_On_Input.ino

https://www.tinkercad.com/things/ecNxnJxaVhb

等等，不要点击

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Arduino Code?

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Team Building & Negotiation Skills

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STEAM Clown ™️ Production

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What Materials Can You Use?

Duct Tape
Dominos
Blocks
Legos
Hot Glue
Cardboard
PVC
Marbles
Ping Pong Balls
Hot Wheels…

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Design Thinking & Planning

What Will You Build?

Spend 10 minutes Planning

What materials will you need?
What Engineering challenges will you encounter?

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10 Minutes

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How To Launch?

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Ready?

Go Build!!!!!!

准备好？去建造！

Zhǔnbèi hǎo? Qù jiànzào!

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Thank You…

Questions?

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Jim Burnham (AKA STEAM Clown)

Mechatronics Engineering Instructor at Silicon Valley Career Technical Education (SVCTE)
Engineering Teacher, Curriculum Developer, Workshop & Conference Presenter
LinkedIn - https://www.linkedin.com/in/jim-burnham-2243018/
Top Clown at TopClown@STEAMClown.org
Mechatronics Engineering Instructor (AKA Fire Breathing Robots)
Want to Support a Teacher? - Here Is How Can You Help

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