Connect Your ESP32 — PlatformIO

Download the Minimalist SDK

Download the SDK and unzip it. You'll get three folders: device_id, wifi_tools, and mqtt. That's the whole SDK.

Create your project

Create a new folder and set it up like this:

ohioiot-connect/
├── platformio.ini
├── config/
│   └── config/
│       └── credentials.h
├── minimalist/
│   ├── device_id/
│   ├── wifi_tools/
│   └── mqtt/
└── src/
    └── main.cpp

Drop the three SDK folders into minimalist/.

platformio.ini

Create platformio.ini in the project root:

[platformio]
default_envs = dev

[env:dev]
platform      = espressif32
board         = esp32dev
framework     = arduino
monitor_speed = 115200

lib_deps =
    knolleary/PubSubClient@^2.8

lib_extra_dirs =
    config
    minimalist

If your board isn't esp32dev, change that one line. Everything else stays the same.

Credentials

Create config/config/credentials.h with your values from the Settings page in the dashboard:

#define WIFI_SSID   "YourWiFiName"
#define WIFI_PASS   "YourWiFiPassword"

#define MQTT_HOST   "mqtt.ohioiot.com"
#define MQTT_PORT   8883
#define MQTT_USER   "larry"
#define MQTT_PASS   "your_mqtt_password"

Port 8883 is the TLS port. Don't change it.

The sketch

Open src/main.cpp and paste this:

#include <Arduino.h>
#include "credentials.h"
#include "device_id.h"
#include "wifi_tools.h"
#include "mqtt.h"

char DEVICE_ID[9];

void setup() {

    Serial.begin(115200);
    Serial.println("\n\n  booting...\n");

    device_id.get_or_set(DEVICE_ID);

    wifi_tools.begin(WIFI_SSID, WIFI_PASS);

    mqtt.setup(MQTT_HOST, MQTT_PORT, DEVICE_ID, MQTT_USER, MQTT_PASS);
}

void loop() {

    if (wifi_tools.is_connected) {
        mqtt.maintain();
    } else {
        wifi_tools.reconnect();
        mqtt.report_disconnect();
    }
}

Flash and watch

Click Upload in PlatformIO. Open the Serial Monitor at 115200 baud. You should see:

  booting...

	existing deviceID: a8f3k2m1

	wifi connecting...
	wifi connected...

	mqtt connecting...
	mqtt connected...