ESP-WROOM-32

Components

• Wemos ESP-WROOM-32
• Micro USB to USB cable

Setup Your Environment

Arduino IDE

• Install the Arduino IDE (Integrated development environment). You can download it for Mac OS X, Windows and Linux here.

Detailed instructions can be found below:

• Installing the Arduino IDE for Windows
• Installing the Arduino IDE for Mac
• Installing the Arduino IDE for Linux

Installing the board definitions

• Start the Arduino application and open Preferences
• Enter https://dl.espressif.com/dl/package_esp32_index.json into the Additional Board Manager URLs field. If you need more than one, they can be separated with commas

• Go to Tools > Board > Boards Manager
• Search for esp32.
• When found, select version 1.0.1 and click Install

Selecting the board and port

Once you've got it connected to your computer, get the name of your device's port using one of the following steps:

Linux and Mac OS X

• Download and install the FTDI drivers from <a href="https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers"target="_blank">here. Select the appropriate version for your operating system and architecture.
• Open a terminal window and run the command `ls /dev/tty*
• Look for a device with the name that begins with /dev/tty e.g. /dev/tty.usbmodemPy343431 on MAC or /dev/ttyUSB0/dev/ttyACM0 on Linux.

Windows

• Download and install the FTDI drivers from <a href="https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers"target="_blank">here. Select the appropriate version for your operating system and architecture.
• Open the Windows start menu and search for Device Manager
• The COM port for the Pycom device will be listed as USB Serial Device or something similar
• Keep note of the COM port (e.g. COM4)

Install the required libraries

• In the Arduino IDE, Go to Sketch > Include Libraries > Manage Libraries

Install each of the following libraries by searching for their name in the search bar within the modal. A button will appear in the bottom right of the box that will allow you to install the library.

• WiFi
• ArduinoHttpClient
• ArduinoJson

Create the Sketch

• Click on File > New to create a new Sketch.
• Copy and paste the publish event example code below in place of the empty setup() and loop() functions

#include <ArduinoJson.h>

#include <WiFi.h>

#include <ArduinoHttpClient.h>

#include <Arduino.h>

​

const char* ssid     = "your-ssid"; // Your WiFi ssid

const char* password = "your-password"; //Your Wifi password

​

// Get this sccret key from the wia dashboard. It should start with `d_sk`

const char* device_secret_key = "your-device-secret-key";

​

// Wia API parameters

char server[] = "api.wia.io";

char path[] = "/v1/events";

int port = 80;

​

WiFiClient client;

int status = WL_IDLE_STATUS;

​

StaticJsonDocument<200> jsonBuffer;

HttpClient httpClient = HttpClient(client, server, port);

JsonObject root = jsonBuffer.to<JsonObject>();

​

​

void setup() {

  // initialize serial communications and wait for port to open:

  Serial.begin(115200);

  while (!Serial) {

    ; // wait for serial port to connect. Needed for native USB port only

  }

  WiFi.begin(ssid, password);

  Serial.print("Attempting to connect to SSID: ");

  Serial.print(ssid);

  // attempt to connect to WiFi network:

  while (WiFi.status() != WL_CONNECTED) {

    Serial.print(".");

    // Connect to WPA/WPA2 network. 

    // wait 5 seconds for connection:

    delay(5000);

  }

​

  Serial.print("IP address: ");

  Serial.println(WiFi.localIP());

  Serial.println("connecting...");

}

​

// Loop function runs continuously

void loop() {

  root["name"] = "hello-wia";

  root["data"] = "";

​

  // if you get a connection, report back via serial:

  if (client.connect(server, port)) {

​

    sendToWia(root);

​

  } else {

    // if you didn't get a connection to the server:

    Serial.println("connection failed");

  }

   delay(3000); // Wait for 3 seconds to post again

}

​

// Adds the correct headers for HTTP and sends Data to Wia

void sendToWia(JsonObject& data) {

  String dataStr = ""; 

  serializeJson(data, dataStr); 

  httpClient.beginRequest();

  httpClient.post(path);

  httpClient.sendHeader("Content-Type", "application/json");

  httpClient.sendHeader("Content-Length", dataStr.length());

  httpClient.sendHeader("Authorization", "Bearer " + String(device_secret_key));

  httpClient.beginBody();

  httpClient.print(dataStr); 

  httpClient.endRequest();

}

Replace the following values of the following variables names (Place the correct value between the quotation marks right of the variable names in the code):

• ssid - with your WiFi network name.
• password - with your WiFi network password.
• device_secret_key with your device secret key from the Wia Dashboard (the one that begins with d_sk).

Selecting Board and Port in the Arduino IDE

• Select the Wemos Lollin 32 board type by going to Tools > Board
• Select the port that matches from above

Upload the code

• Go to Sketch > Upload to send it to your ESP-WROOM-32 .

Viewing your output

• Click on button on the right hand of the screen to view your Serial monitor (Denoted in image below)
• Make sure the baud rate is set to 1152000 (Shown in red rectangle in image below)

Now go to your device in the Wia dashboard and you should see the data appearing in the debugger.

Common errors

If you encounter an error like the one denoted in the image below, check if your board and port are correctly set in the Tools menu