WebSocketTelemetry.ino

/**
 * WebSocketTelemetry - Real-time telemetry over WebSocket (Arduino)
 *
 * The Arduino counterpart to examples/esp32_websocket. Streams metrics to your
 * Plexus dashboard over a persistent WebSocket connection (<100ms latency)
 * instead of one-shot HTTPS POSTs.
 *
 * Requires:
 *   - The "WebSockets" library by Markus Sattler (Links2004) — install via
 *     Library Manager (Arduino IDE) or lib_deps (PlatformIO).
 *   - WebSocket support enabled at compile time: this transport is OFF by
 *     default on Arduino, so build with the flag:
 *        Arduino IDE  : add  -DPLEXUS_ENABLE_WEBSOCKET=1  to your build flags
 *        PlatformIO   : build_flags = -DPLEXUS_ENABLE_WEBSOCKET=1
 *
 * Hardware: ESP32 (recommended) or ESP8266 with WiFi.
 *
 * Setup:
 *   1. Set WIFI_SSID / WIFI_PASSWORD below
 *   2. Get an API key from https://app.plexus.company → Add Device
 *   3. Set PLEXUS_API_KEY, SOURCE_ID, and ORG_ID (your org, e.g. "org_abc123")
 *   4. Upload and open Serial Monitor at 115200 baud
 *   5. Watch data appear live in your Plexus dashboard
 */

#if defined(ESP32)
  #include <WiFi.h>
  #include <time.h>
#elif defined(ESP8266)
  #include <ESP8266WiFi.h>
  #include <time.h>
#endif

#include "plexus.hpp"

#if !PLEXUS_ENABLE_WEBSOCKET
#error "Enable the WebSocket transport: build with -DPLEXUS_ENABLE_WEBSOCKET=1 and install the WebSockets library."
#endif

// ── Configuration ──────────────────────────────────────────────────────────

const char* WIFI_SSID      = "YourWiFiSSID";
const char* WIFI_PASSWORD  = "YourWiFiPassword";
const char* PLEXUS_API_KEY = "plx_your_api_key_here";
const char* SOURCE_ID      = "esp32-ws";
// org_id is OPTIONAL: the gateway resolves your org from the API key. Only set
// it (and uncomment the plexus_set_org_id call below) for a self-hosted gateway
// that requires explicit org routing.
// const char* ORG_ID      = "org_your_org_id";

// ── Globals ────────────────────────────────────────────────────────────────

PlexusClient plexus(PLEXUS_API_KEY, SOURCE_ID);

unsigned long lastReadMs = 0;
const unsigned long READ_INTERVAL_MS = 1000;

// ── NTP time sync (timestamps require a real clock) ──────────────────────────

static void syncTime() {
    configTime(0, 0, "pool.ntp.org", "time.nist.gov");
    Serial.print("Syncing time");
    time_t now = time(nullptr);
    while (now < 1700000000) {   // wait until clock is past 2023
        delay(250);
        Serial.print(".");
        now = time(nullptr);
    }
    Serial.println(" done");
}

// ── Setup ──────────────────────────────────────────────────────────────────

void setup() {
    Serial.begin(115200);
    delay(100);
    Serial.println("\n--- Plexus WebSocket Telemetry ---");

    // Connect to WiFi
    WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
    Serial.print("Connecting to WiFi");
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.printf("\nConnected! IP: %s\n", WiFi.localIP().toString().c_str());

    // NTP — needed for accurate metric timestamps
    syncTime();

    if (!plexus.isValid()) {
        Serial.println("ERROR: Failed to initialize Plexus client");
        return;
    }
    Serial.printf("Plexus SDK v%s ready\n", plexus_version());

    plexus_client_t* px = plexus.handle();

    // Responsive flushing for a live dashboard
    plexus_set_flush_interval(px, 500);

    // Dual transport: WebSocket for real-time + HTTP for persistence &
    // first-time device creation. Keep http_persist on (mirrors esp32_websocket).
    plexus_set_http_persist(px, true);

    // Self-hosted gateways only — explicit org routing:
    // plexus_set_org_id(px, ORG_ID);

    // Open the WebSocket. Non-blocking — plexus.tick() drives the handshake.
    plexus_err_t wsErr = plexus_ws_connect(px);
    if (wsErr != PLEXUS_OK) {
        Serial.printf("WS connect failed: %s — will retry / fall back to HTTP\n",
                      plexus_strerror(wsErr));
    }
}

// ── Loop ───────────────────────────────────────────────────────────────────

void loop() {
    unsigned long now = millis();

    if (now - lastReadMs >= READ_INTERVAL_MS) {
        lastReadMs = now;

        // Replace with your actual sensor reading
        float temperature = 20.0 + random(0, 100) / 10.0;
        float humidity    = 40.0 + random(0, 200) / 10.0;

        plexus.send("temperature", temperature);
        plexus.send("humidity", humidity);

        // Surface WS connection state for diagnostics
        plexus_ws_state_t state = plexus_ws_state(plexus.handle());
        plexus.send("ws_connected", state == PLEXUS_WS_CONNECTED ? 1.0 : 0.0);
    }

    // tick() drives auto-flush AND the WebSocket state machine. On Arduino it
    // also pumps the synchronous WebSocket client, so call it frequently.
    plexus_err_t err = plexus.tick();
    if (err != PLEXUS_OK && err != PLEXUS_ERR_NO_DATA) {
        Serial.printf("Error: %s\n", plexus_strerror(err));
    }

    delay(20);
}