On this page

• Introduction
• Prerequisites
• List of hardware and pinouts
• Wiring schemes
  • Programming/flashing scheme
  • Final schema (Battery Powered)
• IoT Hub configuration
  • Provision your device
  • Provision your dashboard
• Programming the ESP8266
  • Step 1. ESP8266 and Arduino IDE setup.
  • Step 2. Install Arduino libraries.
  • Step 3. Prepare and upload a sketch.
• Autonomous operation
• Troubleshooting
• Data visualization
• See also
• Next steps

Introduction

IoT Hub is an open-source server-side platform that allows you to monitor and control IoT devices. It is free for both personal and commercial usage and you can deploy it anywhere. If this is your first experience with the platform we recommend to review what-is-iothub page and getting-started guide.

This sample application will allow you to control GPIO of your ESP8266 device using IoT Hub web UI. We will observe GPIO control using LEDs connected to the pins. The purpose of this application is to demonstrate IoT Hub RPC capabilities.

The application that is running on ESP8266 is written using Arduino SDK which is quite simple and easy to understand. ESP8266 offers a complete and self-contained Wi-Fi networking solution. ESP8266 pushes data to IoT Hub server via MQTT protocol by using PubSubClient library for Arduino. Current GPIO state and GPIO control widget is visualized using built-in customizable dashboard.

The video below demonstrates the final result of this tutorial.

Prerequisites

You will need to have IoT Hub server up and running. The easiest way is to use Live Demo server.

The alternative option is to install IoT Hub using Installation Guide. Windows users should follow this guide. Linux users that have docker installed should execute the following commands:

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mkdir -p ~/.mytb-data && sudo chown -R 799:799 ~/.mytb-data
mkdir -p ~/.mytb-logs && sudo chown -R 799:799 ~/.mytb-logs
docker run -it -p 9090:9090 -p 7070:7070 -p 1883:1883 -p 5683-5688:5683-5688/udp -v ~/.mytb-data:/data \
-v ~/.mytb-logs:/var/log/thingsboard --name mytb --restart always thingsboard/tb-postgres

These commands install IoT Hub and load demo data and accounts.

IoT Hub UI will be available using the URL: http://localhost:8080. You may use username tenant@thingsboard.org and password tenant. More info about demo accounts is available here.

List of hardware and pinouts

• ESP8266 module

• USB to TTL

  • With DTR & RTS

  

  • Or Without DTR & RTS

  

• Breadboard

• 2 female-to-female jumper wires

• 7 female-to-male jumper wires

• 2 LEDs

• 3.3V power source (for example 2 AA batteries)

Wiring schemes

Programming/flashing scheme

The following picture summarizes the connections for this project in programming/debug mode:

Final schema (Battery Powered)

The final picture:

IoT Hub configuration

Note IoT Hub configuration steps are necessary only in case of local IoT Hub installation. If you are using Live Demo instance all entities are pre-configured for your demo account. However, we recommend reviewing this steps because you will still need to get device access token to send requests to IoT Hub.

Provision your device

This step contains instructions that are necessary to connect your device to IoT Hub.

Open IoT Hub Web UI (http://localhost:8080) in browser and login as tenant administrator

• login: tenant@thingsboard.org
• password: tenant

Go to “Devices” section. Click “+” button and create a device with the name “ESP8266 Demo Device”.

Once device created, open its details and click “Manage credentials”. Copy auto-generated access token from the “Access token” field. Please save this device token. It will be referred to later as $ACCESS_TOKEN.

Click “Copy Device ID” in device details to copy your device id to the clipboard. Paste your device id to some place, this value will be used in further steps.

Provision your dashboard

Download the dashboard file using this link. Use import/export instructions to import the dashboard to your IoT Hub instance.

Programming the ESP8266

Step 1. ESP8266 and Arduino IDE setup.

In order to start programming ESP8266 device, you will need Arduino IDE installed and all related software.

Download and install Arduino IDE.

After starting Arduino IDE, open the preferences from the ‘file’ menu.

Paste the following URL to the “Additional board managers URL”: http://arduino.esp8266.com/stable/package_esp8266com_index.json

Close the screen by clicking the OK button.

Now we can add the board ESP8266 using the board manager.

In the menu tools, click on the menu option Board: “Most likely Arduino UNO”. There you will find the first option “Board Manager”.

Type in the search bar the 3 letters ESP. Locate and click on “esp8266 by ESP8266 Community”. Click on install and wait for a minute to download the board.

Note that this tutorial was tested with the “esp8266 by ESP8266 Community” version 2.3.0.

In the menu Tools “Board “Most likely Arduino UNO” three new boards are added.

Select “Generic ESP8266 Module”.

Prepare your hardware according to the Programming/flashing scheme. Connect USB-TTL adapter with PC.

In the menu Tools, select the corresponding port of the USB-TTL adapter. Open the serial monitor (by pressing CTRL-Shift-M or from the menu Tools). Set the key emulation to “Both NL & CR” and the speed to 115200 baud. This can be set at the bottom of the terminal screen.

Step 2. Install Arduino libraries.

Open Arduino IDE and go to Sketch -> Include Library -> Manage Libraries. Find and install the following libraries:

• PubSubClient by Nick O’Leary.
• ArduinoJson by Benoit Blanchon

Note that this tutorial was tested with the following versions of the libraries:

• PubSubClient 2.6
• ArduinoJson 5.8.0

Step 3. Prepare and upload a sketch.

Download and open esp8266-gpio-control.ino sketch.

Note You need to edit following constants and variables in the sketch:

• WIFI_AP - name of your access point
• WIFI_PASSWORD - access point password
• TOKEN - the $ACCESS_TOKEN from IoT Hub configuration step.
• thingsboardServer - IoT Hub HOST/IP address that is accessible from within your wifi network. Specify “iothub.magenta.at” if you are using live demo server.

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#include <ArduinoJson.h>
#include <PubSubClient.h>
#include <ESP8266WiFi.h>

#define WIFI_AP "YOUR_WIFI_AP"
#define WIFI_PASSWORD "YOUR_WIFI_PASSWORD"

#define TOKEN "ESP8266_DEMO_TOKEN"

#define GPIO0 0
#define GPIO2 2

#define GPIO0_PIN 3
#define GPIO2_PIN 5

char thingsboardServer[] = "iothub.magenta.at";

WiFiClient wifiClient;

PubSubClient client(wifiClient);

int status = WL_IDLE_STATUS;

// We assume that all GPIOs are LOW
boolean gpioState[] = {false, false};

void setup() {
  Serial.begin(115200);
  // Set output mode for all GPIO pins
  pinMode(GPIO0, OUTPUT);
  pinMode(GPIO2, OUTPUT);
  delay(10);
  InitWiFi();
  client.setServer( thingsboardServer, 1883 );
  client.setCallback(on_message);
}

void loop() {
  if ( !client.connected() ) {
    reconnect();
  }

  client.loop();
}

// The callback for when a PUBLISH message is received from the server.
void on_message(const char* topic, byte* payload, unsigned int length) {

  Serial.println("On message");

  char json[length + 1];
  strncpy (json, (char*)payload, length);
  json[length] = '\0';

  Serial.print("Topic: ");
  Serial.println(topic);
  Serial.print("Message: ");
  Serial.println(json);

  // Decode JSON request
  StaticJsonBuffer<200> jsonBuffer;
  JsonObject& data = jsonBuffer.parseObject((char*)json);

  if (!data.success())
  {
    Serial.println("parseObject() failed");
    return;
  }

  // Check request method
  String methodName = String((const char*)data["method"]);

  if (methodName.equals("getGpioStatus")) {
    // Reply with GPIO status
    String responseTopic = String(topic);
    responseTopic.replace("request", "response");
    client.publish(responseTopic.c_str(), get_gpio_status().c_str());
  } else if (methodName.equals("setGpioStatus")) {
    // Update GPIO status and reply
    set_gpio_status(data["params"]["pin"], data["params"]["enabled"]);
    String responseTopic = String(topic);
    responseTopic.replace("request", "response");
    client.publish(responseTopic.c_str(), get_gpio_status().c_str());
    client.publish("v1/devices/me/attributes", get_gpio_status().c_str());
  }
}

String get_gpio_status() {
  // Prepare gpios JSON payload string
  StaticJsonBuffer<200> jsonBuffer;
  JsonObject& data = jsonBuffer.createObject();
  data[String(GPIO0_PIN)] = gpioState[0] ? true : false;
  data[String(GPIO2_PIN)] = gpioState[1] ? true : false;
  char payload[256];
  data.printTo(payload, sizeof(payload));
  String strPayload = String(payload);
  Serial.print("Get gpio status: ");
  Serial.println(strPayload);
  return strPayload;
}

void set_gpio_status(int pin, boolean enabled) {
  if (pin == GPIO0_PIN) {
    // Output GPIOs state
    digitalWrite(GPIO0, enabled ? HIGH : LOW);
    // Update GPIOs state
    gpioState[0] = enabled;
  } else if (pin == GPIO2_PIN) {
    // Output GPIOs state
    digitalWrite(GPIO2, enabled ? HIGH : LOW);
    // Update GPIOs state
    gpioState[1] = enabled;
  }
}

void InitWiFi() {
  Serial.println("Connecting to AP ...");
  // attempt to connect to WiFi network

  WiFi.begin(WIFI_AP, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("Connected to AP");
}


void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    status = WiFi.status();
    if ( status != WL_CONNECTED) {
      WiFi.begin(WIFI_AP, WIFI_PASSWORD);
      while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
      }
      Serial.println("Connected to AP");
    }
    Serial.print("Connecting toIoT Hub node ...");
    // Attempt to connect (clientId, username, password)
    if ( client.connect("ESP8266 Device", TOKEN, NULL) ) {
      Serial.println( "[DONE]" );
      // Subscribing to receive RPC requests
      client.subscribe("v1/devices/me/rpc/request/+");
      // Sending current GPIO status
      Serial.println("Sending current GPIO status ...");
      client.publish("v1/devices/me/attributes", get_gpio_status().c_str());
    } else {
      Serial.print( "[FAILED] [ rc = " );
      Serial.print( client.state() );
      Serial.println( " : retrying in 5 seconds]" );
      // Wait 5 seconds before retrying
      delay( 5000 );
    }
  }
}

Connect USB-TTL adapter to PC and select the corresponding port in Arduino IDE. Compile and Upload your sketch to the device using “Upload” button.

After the application is uploaded and started it will try to connect to IoT Hub node using mqtt client and upload current GPIOs state.

Autonomous operation

When you have uploaded the sketch, you may remove all the wires required for uploading including USB-TTL adapter and connect your ESP8266 and LEDs directly to the power source according to the Final wiring schema.

Troubleshooting

In order to perform troubleshooting, you should assemble your hardware according to the Programming/flashing scheme. Then connect USB-TTL adapter with PC and select port of the USB-TTL adapter in Arduino IDE. Finally, open “Serial Monitor” in order to view the debug information produced by serial output.

Data visualization

Finally, open IoT Hub Web UI. You can access this dashboard by logging in as a tenant administrator.

In case of local installation:

• login: tenant@thingsboard.org
• password: tenant

In case of live-demo server:

• login: your live-demo username (email)
• password: your live-demo password

See live-demo page for more details how to get your account.

Once logged in, open Dashboards->ESP8266 GPIO Demo Dashboard page. You should observe demo dashboard with GPIO control and status panel for your device. Now you can switch status of GPIOs using control panel. As a result, you will see LEDs status change on the device and on the status panel.

Below is the screenshot of the “ESP8266 GPIO Demo Dashboard”.

See also

Browse other samples or explore guides related to main IoT Hub features:

• Device attributes - how to use device attributes.
• Telemetry data collection - how to collect telemetry data.
• Using RPC capabilities - how to send commands to/from devices.
• Rule Engine - how to use rule engine to analyze data from devices.
• Data Visualization - how to visualize collected data.

Next steps

• Getting started guides - These guides provide quick overview of main IoT Hub features. Designed to be completed in 15-30 minutes.

• Connect your device - Learn how to connect devices based on your connectivity technology or solution.

• Data visualization - These guides contain instructions how to configure complex IoT Hub dashboards.

• Data processing & actions - Learn how to use IoT Hub Rule Engine.

• IoT Data analytics - Learn how to use rule engine to perform basic analytics tasks.

• Advanced features - Learn about advanced IoT Hub features.

• Contribution and Development - Learn about contribution and development in IoT Hub.