Spaceship Interface:
Saturday, September 16, 2023
Thursday, September 14, 2023
Lesson 9- Control Servomotor
A servo motor is a specialized motor whose direction can be precisely set
This code uses the servo library. Libraries are code that adds additional functions to Arduino.
For example, to use a servo motor, we need to:
(1) #include <Servo.h>. //include the servo library
(2) Servo myservo; // create servo object to control a servo
(3) myservo.attach(9); // attaches the servo on pin 9 to the servo object
(4) myservo.write(pos); write the servo position( 0 to 180)
#include <Servo.h>
Servo myservo; // create servo object to control a servo
// twelve servo objects can be created on most boards
int pos = 0; // variable to store the servo position
void setup() {
myservo.attach(9); // attaches the servo on pin 9 to the servo object
}
void loop() {
for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
// in steps of 1 degree
myservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15 ms for the servo to reach the position
}
for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
myservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15 ms for the servo to reach the position
}
}
Lesson 8- LED Fade
While the Arduino Uno cannot output a continuously varying(analog) voltage, it can simulate this using analogWrite
for example:
analogWrite(3, 128); //sets pin 3 to half-brightness.
,int led = 9; // the PWM pin the LED is attached to
int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by
// the setup routine runs once when you press reset:
void setup() {
// declare pin 9 to be an output:
pinMode(led, OUTPUT);
}
// the loop routine runs over and over again forever:
void loop() {
// set the brightness of pin 9:
analogWrite(led, brightness);
// change the brightness for next time through the loop:
brightness = brightness + fadeAmount;
// reverse the direction of the fading at the ends of the fade:
if (brightness <= 0 || brightness >= 255) {
fadeAmount = -fadeAmount;
}
// wait for 30 milliseconds to see the dimming effect
delay(30);
}
Related:
Substitute a DC Motor for the LED
// the setup routine runs once when you press reset:
int motorPin = 12;
void setup() {
// initialize serial communication at 9600 bits per second:
Serial.begin(9600);
}
// the loop routine runs over and over again forever:
void loop() {
// read the input on analog pin 0:
int sensorValue = analogRead(A0);
// Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
float voltage = sensorValue * (5.0 / 1023.0);
analogWrite(motorPin, sensorValue / 4);
Serial.println(voltage);
}
Lesson 7- Read a Sensor(Photocell)
A photoresistor changes its resistance depending on how much light is falling on it. In the dark, its resistance can be 100K ohm or more; in light, it can decrease to 5K or less.
We will be reading the voltage on pin A0, using the analogRead function.
// the setup routine runs once when you press reset:
void setup() {
// initialize serial communication at 9600 bits per second:
Serial.begin(9600);
}
// the loop routine runs over and over again forever:
void loop() {
// read the input on analog pin 0:
int sensorValue = analogRead(A0);
// Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
float voltage = sensorValue * (5.0 / 1023.0);
// print out the value you read:
Serial.println(voltage);
}
Use the Serial Monitor to see the output voltage. Make sure the Baud Rate is the same as in the sketch(typically 9600).
Lesson 6: Multiple LEDS
Try adding multiple LEDS, blinking in order:
Write code that turns multiple LEDs on and off- use the Copy and Paste functions to save time typing!
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(7, OUTPUT);
pinMode(9, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(7, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(7, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
digitalWrite(9, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(9, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
Lesson 5: The Blink Sketch- Light an LED
The resistor limits the amount of current
Example Sketch: Blink
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
In setup, we define the built-in LED(Pin 13) as an Output. You could assign another pin (2-12) as an output as well.
The check mark verifies that the code is grammatically correct, such as all statements end with semicolons, all functions are enc,osed in curly brackets {. }. the right arrow uploads it to the board. Make sure you select the correct board and port.
Try changing the delay times in the code! Then change pin numbers!
Lesson 4: Structure of a Sketch(Program)
Statements are always followed by semicolons;
Example 1: Servo "Knob"
#include <Servo.h>
Servo myservo; // create servo object to control a servo
int potpin = A0; // analog pin used to connect the potentiometer
int val; // variable to read the value from the analog pin
void setup() {
myservo.attach(9); // attaches the servo on pin 9 to the servo object
}
void loop() {
val = analogRead(potpin); // reads the value of the potentiometer (value between 0 and 1023)
val = map(val, 0, 1023, 0, 180); // scale it for use with the servo (value between 0 and 180)
myservo.write(val); // sets the servo position according to the scaled value
delay(15); // waits for the servo to get there
}
Example 2: "Blink"
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
The Arduino IDE(Integrated Development Environment) can be downloaded at:
There is also an online version at https://create.arduino.cc/editor. Once you log in, your code is saved in the cloud.
Lesson 2: Components and Schematics
Schematic Symbols:
A physical picture can be useful, but it often doesn't communicate the functioning of a circuit.
A schematic explains this much better:
Resistors
Activities:
- Draw LED schematics
- Practice reading color code on resistors
Ohm's Law Calculator: https://ohmslawcalculator.com/ohms-law-calculator
Solderless Breadboard:
Simple LED circuit:
Lesson 1: Tools
Soldering:
See More on tools at:
Activities:
- Practice cutting and stripping wire
- Soldering Practice Exercises
- Measure voltage, resistance and current with a multimeter
Conventions:
#22 solid wire works best with solderless breadboards
Red wire should indicate power
Black wire should indicate ground
Wednesday, September 13, 2023
Lesson 0: Electricity Basics
What is voltage? Voltage(V) is a measure of electrical force-how hard the electrons are being pushed.
Arduino circuits typically run at 5V; newer devices use 3.3V.
Current is a measure of how many electrons are flowing, and is measured in Amperes or milliamperes(mA =1/1000 of an ampere). For example, LEDs run best at 20 mA; a small motor might draw 200 mA; a string of programmable LEDs might draw 800 mA. An Arduino can supply a maximum of 40 mA on its pins, so we need to use transistors or relays to control larger loads.
Resistance, measured on Ohms or kiloOhms(K), is a measure of how much current flow is resisted. The resistance of a resistor is marked using a color ode.
Ohm's Law: Voltage = Current x Resistance or V=I x R
LED Basics:
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