selected input/output - sensors and actuators

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Sensors & Actuators
SelectedI/OsEueung Mulyana
https://eueung.github.io/012017/inout
CodeLabs | Attribution-ShareAlike CC BY-SA

Outline
Preparation
Light/Laser Sensor
PIR Sensor
LM35 & DHT11
Processing & Local Visualization
Ultrasonic Sensor
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Preparation Notes
We reuse the previous nRF24L01+ example (Simple Remote Control) with some changes i.e.:
for simplicity both nodes are now Nano-based, an LCD is attached to Node-2 for a better
communication and debugging experience.
In the next examples, the switch will be replaced with laser and PIR
sensors.
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I2C LCD1602
An LCD display that can display a max
of 16x2 characters.
As the pin resources of ucontroller is limited, your project may
be not able to use normal LCD shield after connected with a
certain quantity of sensors/actuators i.e. if you are doing more
than a simple project, you may be out of pins using a normal
LCD shield. With this I2C interface LCD module, you only need 2
lines (I2C) to display information.
Interface: connect the I2C LCD1602 to the I2C port of Arduino
(SDA - A4 and SCL - A5) and power this module with 5V.
Ref: arduino-info, elecrow

Node-1 & Node-2 (Both with nRF24L01+) 6 / 74

Node-1 (Remote Switch / Sensor Node) 7 / 74

Install I2C LiquidCrystal Library 11 / 74

#include <SPI.h>
#include "nRF24L01.h"
#include "RF24.h"
RF24 myRadio (7, 8);
const int SW1 = 5;
const int SW2 = 6;
byte addresses[][6] = {"1Node"};
int dataTransmitted;
int button1;
int button2;
void setup()
{
pinMode(SW1, INPUT);
pinMode(SW2, INPUT);
button1 = 0;
button2 = 1;
dataTransmitted = 10;
Serial.begin(115200);
delay(1000);
myRadio.begin();
myRadio.setRetries(0,15);
myRadio.setChannel(108);
myRadio.setPALevel(RF24_PA_MAX);
myRadio.openWritingPipe( addresses[0]);
delay(1000);
}
void loop()
{
int newButton = digitalRead(SW1);
if (newButton != button1) {
button1 = newButton;
if (button1 == HIGH){
dataTransmitted = 20;
} 12 / 74
Node-1

#include <SPI.h>
#include "nRF24L01.h"
#include "RF24.h"
RF24 myRadio (7, 8);
byte addresses[][6] = {"1Node"};
int dataReceived;
const int LED = 2;
#include <Wire.h>
#include <LiquidCrystal_PCF8574.h>
LiquidCrystal_PCF8574 lcd(0x27);
int lcdexist;
unsigned long started_waiting_at = 0;
bool bklight = false;
void setup()
{
pinMode(LED, OUTPUT);
Serial.begin(115200);
delay(1000);
myRadio.begin();
myRadio.setAutoAck(1);
myRadio.setChannel(108);
myRadio.setPALevel(RF24_PA_MAX);
myRadio.openReadingPipe(1, addresses[0]);
myRadio.startListening();
Wire.begin();
Wire.beginTransmission(0x27);
lcdexist = Wire.endTransmission();
lcd.begin(16, 2);
}
void loop()
{
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Node-2

Laser Mini Transmitter & Receiver Module 17 / 74

Light/Laser Receiver Module
Utilizing LDR and Voltage Comparator for Digital Output
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LDR
LDR or Light Dependent Resistor (sometimes called
a photoresistor or photocell) is a two-terminal,
resistive component that increases or decreases its
resistance depending on the light it senses. An LDR
initially has a very high resistance. But, as light falls
on it, the resistance will drop, allowing more current
through.
Ref: Earthshine Design

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LDR Sensor Module
LDR sensor module is used to detect the intensity of
light. It might have both analog output pin and
digital output pin labelled as AO and DO
respectively on the board. When there is light, the
resistance of LDR will become low according to the
intensity of light. The greater the intensity of light,
the lower the resistance of LDR. The sensor has a
potentiometer knob that can be adjusted to change
the sensitivity of LDR towards light.
Ref: LDR Sensor Module

Switch Replacement with a Laser Receiver 21 / 74

Switch Replacement with a Laser Receiver 22 / 74

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PIR Sensor
A PIR (Passive Infra-Red) sensor is an electronic
sensor that measures infrared light radiating from
objects in its eld of view. Normally this type of
sensor would be used as a motion or proximity
sensor. Quite often they are referred to as: PIR,
Motion, Proximity, or Pyroelectric sensor.
The sensor in the PIR detects or "reads" infrared radiation "emitted"
from objects all around us. Each object with a temperature above
absolute zero will radiate infrared, even us humans, and even though we
mere humans cannot see this. Note that the PIR just uses a relatively
simple sensor - it is most de nitely not an IR camera!
Ref: Testing and Playing with PIR sensors @Tweaking4All

Switch Replacement with a PIR Sensor 25 / 74

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LM35
LM35 is a linear temperature sensor with the output
voltage calibrated in centigrade celsius. 1 degree
celsius makes an output voltage of 10mV. So when
you have room temperature at 22C the LM35 gives
you a voltage of 220mV = 0.22V.
The sensor has only 3 pins: VCC which can be between +4V and +20V,
GND and Vout. Vout has to be connected to one of the analog inputs and
that's all - in most cases.
Ref: connecting an arduino with a LM35 temperature sensor @heliosoph

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DHT11
DHT11 is a temperature and humidity sensor with a
calibrated digital signal output.
The DHT11 sensor has four pins. Connect the rst pin on left of sensor
('VCC') to 5V of your board, the second pin ('Data') to a digital pin and
the fourth pin ('GND') to ground. When the connecting cable is shorter
than 20m, a 5K pull-up resistor between the second Pin of sensor and 5V
is recommended.
Ref: DHT11 Temperature and Humidity Sensor Example @arduino.org

Install Library for DHTxx Sensors 30 / 74

float tlm35;
void setup() {
Serial.begin(9600);
//analogReference(INTERNAL);
}
void loop() {
tlm35 = 0.0;
for(int j = 0; j < 10; j++) {
tlm35 += analogRead(A0);
delay(20);
}
tlm35 = tlm35 * 5.0 * 10.0 / 1023.0;
//tlm35 = tlm35 * 1.1 * 10.0 / 1023.0;
Serial.println(tlm35);
}
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LM35

#include "DHT.h"
#define DHTPIN 3
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);
void setup() {
Serial.begin(9600);
dht.begin();
}
void loop() {
delay(2000);
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
float h = dht.readHumidity();
float t = dht.readTemperature();
if (isnan(h) || isnan(t)) {
Serial.println("Failed to read from DHT sensor!");
return;
}
Serial.println(t);
}
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DHT11

Local Visualization & UI
Processing
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Processing
Processing is a exible software sketchbook and a
language for learning how to code within the
context of the visual arts.
Since 2001, Processing has promoted software literacy within the visual
arts and visual literacy within technology. There are tens of thousands of
students, artists, designers, researchers, and hobbyists who use
Processing for learning and prototyping.
Ref: Processing.org

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Processing is an open source language/
development tool for writing programs in other
computers. Useful when you want those other
computers to talk with an Arduino, for instance to
display or save some data collected by the Arduino.
How to Work with Processing?
Write Arduino sketch as usual, except for input/output intended to
be retrieved from or sent to Processing
Write Processing program that receives/sends data from/to
Arduino
If you just want to control an Arduino board from a Processing program,
you may want to use the Arduino Library for Processing.
Ref: Arduino Playground - Processing

Switch Example
Ref: Electronics @Processing.org 36 / 74

int switchPin = 5;
void setup() {
pinMode(switchPin, INPUT);
Serial.begin(9600);
delay(1000);
}
void loop() {
if (digitalRead(switchPin) == HIGH) {
//Serial.println(1);
Serial.write(1);
} else {
//Serial.println(0);
Serial.write(0);
}
delay(100);
}
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Arduino

import processing.serial.*;
Serial port;
int val;
String stext;
void setup() {
size(200, 200);
frameRate(10);
port = new Serial(this, "/dev/ttyUSB0", 9600);
}
void draw() {
if (0 < port.available()) {
val = port.read();
}
background(255);
if (val == 0) {
fill(0);
stext = "OFF";
} else {
fill(255,0,0);
stext = "ON";
}
rect(50, 50, 100, 100);
textAlign(CENTER);
textSize(30);
fill(255);
text(stext, 100, 112);
}
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Processing

Using Arduino IDE Serial Plotter 39 / 74

Using Arduino IDE Serial Plotter 40 / 74

Controlling a Servo
Ref: Electronics @Processing.org 41 / 74

Micro Servo
Tower Pro SG90 42 / 74

#include <Servo.h>
Servo myservo;
int servoPin = 4;
int val = 0;
void setup() {
myservo.attach(servoPin);
Serial.begin(9600);
}
void loop() {
if (Serial.available()) {
val = Serial.read();
}
myservo.write(val);
delay(15);
}
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Arduino

Serial port;
float mx = 0.0;
void setup() {
size(200, 200);
noStroke();
frameRate(10);
port = new Serial(this, "/dev/ttyUSB0", 9600);
}
void draw() {
background(0);
fill(204);
rect(40, height/2-15, 120, 25);
float dif = mouseX - mx;
if (abs(dif) > 1.0) {
mx += dif/4.0;
}
mx = constrain(mx, 50, 149);
noStroke();
fill(255);
rect(50, (height/2)-5, 100, 5);
fill(204, 102, 0);
rect(mx-2, height/2-5, 4, 5);
int angle = int(map(mx, 50, 149, 0, 180));
port.write(angle);
}
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Processing

Arduino Built-In Example - Graph 45 / 74

void setup() {
Serial.begin(9600);
}
void loop() {
Serial.println(analogRead(A0));
// wait a bit for the analog-to-digital converter
// to stabilize after the last reading:
delay(2);
}
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Arduino

Serial myPort; // The serial port
int xPos = 1; // horizontal position of the graph
float inByte = 0;
void setup () {
size(400, 300);
myPort = new Serial(this, "/dev/ttyUSB0", 9600);
myPort.bufferUntil('n');
background(0);
}
void draw () {
stroke(127, 34, 255);
line(xPos, height, xPos, height - inByte);
if (xPos >= width) {
xPos = 0;
background(0);
} else {
xPos++;
}
}
void serialEvent (Serial myPort) {
String inString = myPort.readStringUntil('n');
if (inString != null) {
inString = trim(inString);
inByte = float(inString);
println(inByte);
inByte = map(inByte, 0, 1023, 0, height);
//inByte = map(inByte, 0, 100, 0, height);
}
}
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Processing

Circuit & Processing Plot 48 / 74

HC-SR04
Ultrasonic Sensor
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Ultrasonic Sensor
HC-SR04 ultrasonic ranging sensor provides 2cm to
400cm of non-contact measurement functionality
with a ranging accuracy that can reach up to 3mm. It
is a very a ordable proximity/distance sensor that
has been used mainly for object avoidance in
various robotics projects.
Each HC-SR04 module includes an ultrasonic transmitter, a receiver and
a control circuit. It has 4 pins: VCC, GND, Trigger and Echo pin.

Install Arduino NewPing Library 51 / 74

Install Processing gra ca Library 52 / 74

#include <NewPing.h>
#define TRIGGER_PIN 3
#define ECHO_PIN 4
#define MAX_DISTANCE 300
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);
void setup() {
Serial.begin(9600);
}
void loop() {
delay(500);
Serial.println(sonar.ping_cm());
}
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Arduino

import grafica.*;
GPlot plot;
int i = 0;
int points = 100;
public float[] values;
Serial myPort;
float inByte = 0;
void setup(){
size (900,450);
GPointsArray points1 = new GPointsArray(points);
values = new float[points];
for (i = 0; i < points; i++) {
points1.add(i,0);
values[i]=0;
}
plot = new GPlot(this);
plot.setPos(25, 20);
plot.setDim(750, 310);
plot.setXLim(0, points);
plot.setYLim(0, 310);
plot.setTitleText("Distance");
plot.getXAxis().setAxisLabelText("Sample Time");
plot.getYAxis().setAxisLabelText("cm");
plot.setPoints(points1);
}
void draw() {
background(150);
GPointsArray points1 = new GPointsArray(points);
for (i = 0; i < values.length; i++) { 55 / 74
Processing

Processing Plot with gra ca Library 56 / 74

#include <Servo.h>
#define ECHO_PIN 4
Servo myservo;
int servoPin = 5;
int val = 0;
void setup() {
Serial.begin(9600);
}
void loop() {
val = analogRead(A0);
val = map(val, 0, 1023, 0, 180);
myservo.write(val);
//delay(15);
delay(500);
}
Rotating SR04 with a Servo - Manually via a Potentiometer 57 / 74
Arduino

#include <Servo.h>
#define ECHO_PIN 4
Servo myservo;
int servoPin = 5;
int val = 0;
int lastval = 0;
unsigned long timer;
void setup() {
Serial.begin(9600);
timer = millis();
}
void loop() {
val = analogRead(A0);
val = map(val, 0, 1023, 0, 180);
int dif = val - lastval;
if(abs(dif)>1) {
val = lastval + dif/4;
}
myservo.write(val);
lastval = val;
delay(15);
if((millis()-timer)>500) {
timer = millis();
}
}
Rotating SR04 with a Servo - Try this too! 58 / 74
Arduino

SR04 Sonar
Our previous case can be rearranged to make a simple DIY Sonar
(SOund Navigation And Ranging) system.
The following example was modi ed from Dejan Nedelkovski's code.
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#include <Servo.h>
#define ECHO_PIN 4
Servo myservo;
int servoPin = 5;
const int angle_start = 5;
const int angle_end = 175;
const int delaytime = 20;
void setup() {
Serial.begin(9600);
}
void loop() {
for(int i=angle_start;i<=angle_end;i++){
myservo.write(i);
delay(delaytime);
Serial.print(i);
Serial.print(",");
Serial.print(sonar.ping_cm());
Serial.print(".");
}
for(int i=angle_end;i>angle_start;i--){
myservo.write(i);
delay(delaytime);
Serial.print(i);
Serial.print(",");
Serial.print(sonar.ping_cm());
Serial.print(".");
}
}
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Arduino

String distance="";
String data="";
String noObject;
float pixsDistance;
int iAngle, iDistance;
int index1=0;
int index2=0;
final float MAX_DIST = 300;
//-------------------------------------------------
void setup() {
size(1200, 700);
smooth();
myPort.bufferUntil('.');
orcFont = loadFont("OCRAExtended-30.vlw");
}
//-------------------------------------------------
void draw() {
float covered_height = height*0.935;
noStroke();
fill(0,4);
rect(0, 0, width, covered_height);
fill(98,245,31);
textFont(orcFont);
drawRadar();
drawLine();
drawObject();
drawText();
}
//-------------------------------------------------
void serialEvent (Serial myPort) {
data = myPort.readStringUntil('.');
data = data.substring(0,data.length()-1);
index1 = data.indexOf(",");
angle= data.substring(0, index1);
distance= data.substring(index1+1, data.length());
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Processing

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drawRadar()
drawText()

Refs/Resources
1. LDR Sensor Module Interface With Arduino
2. Using a Photocell @Adafruit
3. Photoresistor @ElectroSchematics
4. Testing and Playing with PIR sensors @Tweaking4All
5. Arduino Playground - Processing
6. Processing Foundation
7. Electronics - Processing.org
8. Typography, Strings and Drawing Text
9. Arduino library for DHT11DHT22, etc Temp & Humidity Sensors
10. A simple and con gurable plotting library for Processing
11. Clipart - Strain Gauge
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ENDEueung Mulyana
https://eueung.github.io/012017/inout
CodeLabs | Attribution-ShareAlike CC BY-SA

selected input/output - sensors and actuators

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