Cassiopeia Ltd - standard Arduino workshop

standard Arduino workshop 2017
Hands-on Arduino introduction
Tom Tobback
www.cassiopeia.hk
2017

some of Tom’s projects
cassiopeia.hk/category/projects/

Before we start… check the connection between your
Arduino board and your laptop:
● plugin your Arduino board USB cable into your laptop
● open Arduino IDE software (www.arduino.cc)
● open the Blink sketch from File>Examples>Basic
● pick the correct port from Tools>Serial Port
● pick the correct board type from Tools>Board “Uno”
● hit ‘upload’ to test the connection
● look for ‘Done uploading’ and check if the onboard LED
is blinking

Arduino: what is it?
Arduino is an open-source electronics
prototyping platform
based on flexible, easy-to-use hardware
and software
It is intended for artists, designers,
hobbyists and anyone interested in
creating interactive objects or
environments
• sensors
• sound
• light
• wifi
• ...

Our program for today
terminology 4
software 2
basic electronics 4
projects 20+
metronome
theremin

Arduino terminology
software:
• IDE
• web editor
• sketch
• uploading
hardware:
• board
• microcontroller (mcu)
• pin headers
• input
• output
• digital/analog
• breadboard
• jumper wires
• components

Arduino vs Raspberry Pi
➔ looks similar
➔ similar price
➔ micro-controller vs
mini-computer
➔ Arduino: IO
➔ Pi: OS
Other popular platforms:
ESP8266, Particle Photon, micro:bit

Arduino boards
➔ many official boards
➔ different sizes
➔ different connections
➔ use same code
➔ mostly compatible
➔ extra functions via shields

Arduino UNO

Arduino-style boards
➔ many copies
➔ many improvements
➔ extra functions included
(Wifi, GPS, motor, Ethernet,...)
➔ use same code
➔ mostly compatible
➔ cheaper!

Arduino software: IDE
➔ Integrated Development Environment
➔ Write sketch -> upload to board
➔ Useful examples
➔ ‘Libraries’ to make our life easier
Always make sure to pick the correct BOARD
➔ Connect using USB cable, pick correct PORT
➔ Upload sketch
➔ Check output of Serial Monitor
➔ Save your sketches..

Arduino software: Web Editor
Same functionality with:
➔ Browser based editor (needs login)
➔ Accessible from any computer
➔ Storage in the cloud
➔ Need to sign up for username
➔ Need to install the Arduino Create plugin for upload

Basic electronics
➔ DC direct current vs alternating current AC
➔ voltage: volts 5V (usb), 3V3, 9V
➔ current: milli ampere 40 mA = 0.04 A
➔ power: watts 1-2 W (USB limit)
➔ resistors: reduce voltage
➔ diodes: one-way + light
➔ capacitors: small battery
➔ schematics

Basic electronics
DIGITAL: on/off
1/0
true/false
high/low
0V/5V
ANALOG: variable 0->5V
Ohm’s law: U = I * R
Kirchoff’s laws:

From prototype to product

Breadboard = connections

Breadboard power rails
5V to red line
GND to blue line
Optional:
connect to other side

Breadboard

Arduino projects for today
➔ Blink: the ‘hello world’ of Arduino pinMode
digitalWrite
delay
➔ Read push button digitalRead
➔ Read potentiometer analogRead
➔ Output to Serial Monitor Serial.print
➔ Buzzer music tone
➔ Potentiometer + blink + buzzer = metronome
➔ Read photoresistor/LDR
➔ Fading (PWM) analogWrite
➔ Input to Serial Monitor Serial.read

Arduino: blink
Blink: the ‘hello world’ of Arduino
220 ohm

resistor colour code
220 ohm = 220 Ω
red red black black (brown)
10k ohm = 10,000 Ω
brown black black red
(brown)

Arduino: ‘blink’ sketch
/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.
Most Arduinos have an on-board LED you can control. On the Uno and
Leonardo, it is attached to digital pin 13. If you're unsure what
pin the on-board LED is connected to on your Arduino model, check
the documentation at http://www.arduino.cc
This example code is in the public domain.
modified 8 May 2014
by Scott Fitzgerald
*/
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin 13 as an output.
pinMode(13, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(13, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(13, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
initialisation
setup { }
loop { }
bonus:
attach a second LED to
pin12 doing exactly
opposite of LED on pin13

Arduino: RGB LED blink
Red Green Blue = primary colours (additive)
V = common negative
R = red positive
B = blue positive
G = green positive
(including resistors)
use digitalWrite to mix colours
e.g. on pin 10, 11, 12

Arduino: RGB LED blink

[optional] Arduino: button
boolean button_pressed = false;
---
pinMode(2, INPUT);
---
button_pressed = digitalRead(2);
if (button_pressed == true) {
digitalWrite(13, HIGH);
}
else {
digitalWrite(13, LOW);
}
use pinMode(2, INPUT_PULLUP);
or: pull-down resistor (e.g. 10kΩ)

Arduino: potentiometer

Arduino: potentiometer
int pot_value; [VARIABLE]
[SETUP]
[LOOP]
pot_value = analogRead(A0);
[change your delay to:]
delay(pot_value);
[analogRead returns 0->1023]
5k ohm

Arduino: Serial Monitor
[SETUP]
Serial.begin(9600);
[LOOP]
[try one by one:]
Serial.print(“hello”);
[or]
Serial.println(“hello”);
[or]
Serial.print(“pot value: “);
Serial.println(pot_value); bonus:
print description of your
program on startup and
format output with t

Arduino: Serial Plotter
[LOOP]
Serial.println(pot_value);

Arduino: metronome
Blink with variable speed, and bpm in serial monitor
How?
read pot_value (analogRead)
print pot_value (Serial.print)
calculate beats per minute (=)
print BPM (Serial.print)
LED ON for 100ms (digitalWrite)
LED OFF for variable time: pot_value
100ms variable pot_value
ON OFF

Arduino: metronome
total ‘beat’ length = 100ms ON + variable OFF
beat_length = 100 + pot_value
beats per minute = (60 * 1000) / beat_length
BPM will vary from 53 to 600
100ms variable pot_value
bonus:
attach a second LED to
pin12 doing exactly
opposite of LED on pin13
ON OFF
total beat length

Arduino: metronome
‘int’ type does not work with large numbers
(larger than around 32000, 16 bits)
type to use = ‘long’
long bpm;
[SETUP]
[LOOP]
bpm = (60 * 1000L) / (100 + pot_value);
bonus:
format your output with t

Arduino: sound
Piezo buzzer = speaker
SYNTAX:
tone(pin, freq);
tone(pin, freq, duration);
noTone(pin);
[SETUP]
[LOOP]
tone(3, 261); [put in correct place!]
noTone(3); [put in correct place!]

Arduino: metronome + sound
● LED on and beep (100ms) + LED off and no beep
● variable speed with potentiometer
● serial monitor BPM
frequency examples (Hz):
C 261
D 293
E 329
G 392
bonus:
try different frequencies

Arduino: light dependent resistor
LDR or photoresistor =
variable resistor, similar to potentiometer -> analogRead
voltage divider: sum=5V and analog input sees 0->5V
1K ohm

int ldr_value;
[SETUP]
[LOOP]
ldr_value = analogRead(A1);
Serial.println(ldr_value);
check on the Serial Monitor for min, max values of the LDR
how to go from e.g. 50-500 values to 200-5000Hz frequencies?
use ‘map’ function

int freq;
[SETUP]
[LOOP]
freq = map(ldr_value, 50, 500, 200, 5000);
tone(3, freq); [just update this line]
SYNTAX: map(value, fromLow, fromHigh, toLow, toHigh)

Basic theremin

Arduino: basic theremin sketch
int pot_value;
int ldr_value;
int freq;
long bpm;
void setup() {
pinMode(13, OUTPUT);
Serial.begin(9600);
}
void loop() {
pot_value = analogRead(A0);
bpm = (60 * 1000L) / (100 + pot_value);
ldr_value = analogRead(A1);
freq = map(ldr_value, 50, 500, 200, 5000);
Serial.print(“BPM: “);
Serial.println(bpm);
digitalWrite(13, HIGH);
tone(3, freq);
delay(100);
digitalWrite(13, LOW);
noTone(3);
delay(pot_value);
}
1
2
3

Advanced theremin
1. Use a pentatonic scale with a lookup table
= table of frequencies on a pentatonic scale, accessible by index
2. Add a 2 step ‘sequencer’
1 loop = constant base note + variable note on second beat
100ms variable pot_value 100ms variable pot_value
base note silence variable pentatonic note silence

Pentatonic theremin
Pentatonic scale with a lookup table
int pentatonicTable[50] = {
0, 19, 22, 26, 29, 32, 38, 43, 51, 58, 65, 77, 86, 103, 115, 129, 154, 173,
206, 231, 259, 308, 346, 411, 461, 518, 616, 691, 822, 923, 1036, 1232,
1383, 1644, 1845, 2071, 2463, 2765, 3288, 3691, 4143, 4927, 5530, 6577,
7382, 8286, 9854, 11060, 13153, 14764 };
OLD: freq = map(ldr_value, 50, 500, 200, 5000);
NEW: freq = pentatonicTable[map(ldr_value, 50, 500, 20, 45)];

2 step sequencer theremin
1 loop = constant base note + variable note on second beat
tone(3, 206); noTone(3); tone(3, freq); noTone(3);
delay(100); delay(pot_value); delay(100); delay(pot_value);
Now you can add steps, change length of steps etc...
100ms variable pot_value 100ms variable pot_value
base note silence variable pentatonic note silence

Arduino: AnalogWrite (PWM)
Analog input = 0 to 5 V
Arduino does not output
a real analog signal (0-5V)
analogWrite(pin, value);
PWM = Pulse Width Modulation
only available on pins 3,5,6,9,10,11
can use this to fade LED
values from 0 to 255 (8 bits)

Arduino: AnalogWrite (PWM)
‘for’ structure = loop for X times
Open sketch: Examples > 03.Analog > Fading
[change your breadboard LED to pin 9]
// fade in from min to max in increments of 5 points:
for(int fadeValue = 0 ; fadeValue <= 255; fadeValue +=5) {
// sets the value (range from 0 to 255):
analogWrite(ledPin, fadeValue);
// wait for 30 milliseconds to see the dimming effect
delay(30);
}

Arduino: input via Serial Monitor
top box of Serial Monitor = input
send data from computer to Arduino - ASCII format (bytes)

Let’s read a number 0-9 for intensity of LED
[remove all commands from loop]
int brightness;
[SETUP]
Serial.begin(9600);
[LOOP]
if (Serial.available()) {
brightness = Serial.read();
Serial.print("Arduino received: ");
Serial.println(brightness);
}
[switch to ‘No line ending’ at bottom of Serial Monitor?]

for analogWrite we need to map the brightness
from 48-57 (ASCII for 0 to 9)
to
0-255 for analogWrite (0% to 100%)
[add this line in the loop]
analogWrite(ledPin, map(brightness, 48, 57, 0, 255));

Arduino: suppliers
ONLINE
➔ Official Arduino shop: http://arduino.cc/
great documentation, projects, forum
➔ Seeedstudio: http://www.seeedstudio.com/depot/
➔ Telesky: https://telesky.world.tmall.com/
➔ Adafruit: http://www.adafruit.com/ great documentation
IN HONG KONG - Apliu St
➔ WECL http://www.weclonline.com/wecl_eng/index.html
➔ Tell How http://tellhow-tech.com/

Arduino: kits
➔ Seeedstudio Sidekick
Arduino kit
➔ Arduino Starter Kit

Dimsum Labs
the hackerspace of HK www.dimsumlabs.com/
community of technology enthusiasts
space for creativity in Sheung Wan
Tuesday evening HackJam
www.facebook.com/groups/hackjamhk/

Thank you
www.cassiopeia.hk
Happy tinkering!

Cassiopeia Ltd - standard Arduino workshop

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