Tutorial 08: Installing Required Libraries

Why Do We Need Libraries?

Libraries are pre-written code that make it easier to work with sensors and components. Instead of writing complex low-level code yourself, you can use libraries that handle the hard work.

OceanRemote firmware uses three main libraries depending on your sensor choice:

• ArduinoJson - Required for ALL boards. Parses the data from OceanRemote servers.
• DHT sensor library - Required if you're using a DHT22 or DHT11 temperature/humidity sensor.
• OneWire + DallasTemperature - Required if you're using a DS18B20 digital temperature sensor.

Library 1: ArduinoJson (Required for All Boards)

ArduinoJson is the most important library. It parses the JSON data sent by OceanRemote servers to control your relays and sensors.

Installation Steps:

1. Open Arduino IDE
2. Go to Sketch → Include Library → Manage Libraries
3. In the search box, type "ArduinoJson"
4. Look for "ArduinoJson by Benoit Blanchon"
5. Click Install (version 6.21.0 or newer)
6. Wait for installation to complete

Verifying ArduinoJson Installation:

1. Go to File → Examples
2. Look for "ArduinoJson" in the list
3. If you see it, the library is installed correctly

// Test code to verify ArduinoJson
#include <ArduinoJson.h>

void setup() {
  Serial.begin(115200);
  Serial.println("ArduinoJson version: ");
  Serial.println(ARDUINOJSON_VERSION);
}

void loop() {}

Upload this test code. If you see a version number in Serial Monitor, it's working!

Library 2: DHT Sensor Library (For DHT22/DHT11)

The DHT22 and DHT11 are popular temperature and humidity sensors. This library makes reading them simple.

Installation Steps:

1. In Library Manager, search for "DHT sensor library"
2. Look for "DHT sensor library by Adafruit"
3. Click Install
4. It will ask to install dependencies. Click Install All (this includes "Adafruit Unified Sensor")

Verifying DHT Installation:

// Test code for DHT22/DHT11
#include <DHT.h>

#define DHTPIN 2
#define DHTTYPE DHT22

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  dht.begin();
  Serial.println("DHT library working!");
}

void loop() {
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  
  if (isnan(h) || isnan(t)) {
    Serial.println("Sensor not connected");
  } else {
    Serial.print("Temp: "); Serial.print(t); Serial.print("°C, ");
    Serial.print("Humidity: "); Serial.print(h); Serial.println("%");
  }
  delay(2000);
}

Library 3: OneWire and DallasTemperature (For DS18B20)

The DS18B20 is a digital temperature sensor that uses the 1-Wire protocol. It's very accurate (±0.5°C) and multiple sensors can share the same pin.

Installation Steps:

1. In Library Manager, search for "OneWire"
2. Find "OneWire by Jim Studt" (or Paul Stoffregen version)
3. Click Install
4. Search for "DallasTemperature"
5. Find "DallasTemperature by Miles Burton"
6. Click Install

Verifying DS18B20 Installation:

// Test code for DS18B20
#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 2
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

void setup() {
  Serial.begin(115200);
  sensors.begin();
  Serial.println("DS18B20 library working!");
}

void loop() {
  sensors.requestTemperatures();
  float temp = sensors.getTempCByIndex(0);
  
  if (temp == -127.0) {
    Serial.println("Sensor not connected");
  } else {
    Serial.print("Temperature: ");
    Serial.print(temp);
    Serial.println("°C");
  }
  delay(1000);
}

Library Installation Summary

Troubleshooting Library Issues

Problem: "ArduinoJson.h: No such file or directory"

• Solution: ArduinoJson is not installed. Go to Library Manager and install it.

Problem: "DHT.h: No such file or directory"

• Solution: DHT library not installed. Install "DHT sensor library by Adafruit".

Problem: "OneWire.h: No such file or directory"

• Solution: OneWire library not installed. Install "OneWire by Jim Studt".

Problem: Multiple library versions conflict

• Solution: Go to Documents/Arduino/libraries (Windows) or ~/Arduino/libraries (Mac/Linux) and delete old versions manually.

Next Steps

Now that your libraries are installed, continue with:

• Tutorial 09: Configuring Board Settings
• Tutorial 10-15: Wiring diagrams for your specific board
• Tutorial 16-20: Working with sensors (DHT22, DS18B20, NTC)
• Return to Tutorial 02: Generate and flash your firmware!