Sensor setup

Point your ESP32 at the endpoint below and include the device key from the Devices tab.

Endpoint

Method: POST · Content-Type: application/json

https://project--670037ee-58ed-4aa3-9988-56cec5e1267e.lovable.app/api/public/readings

The key may be sent in the JSON body as device_key or as the header x-device-key. A successful post returns {"ok":true}.

JSON payload

{
  "device_key": "YOUR_DEVICE_KEY",
  "moisture": 6.4,
  "temperature": 22.5,
  "battery": 3.9,
  "raw": 2310
}

moisture — required, 0–100 percent
temperature, battery, raw — optional extras
recorded_at — optional ISO timestamp; defaults to the time it arrives

Example ESP32 firmware (Arduino)

#include <WiFi.h>
#include <HTTPClient.h>

const char* WIFI_SSID = "your-wifi";
const char* WIFI_PASS = "your-password";

const char* ENDPOINT   = "https://project--670037ee-58ed-4aa3-9988-56cec5e1267e.lovable.app/api/public/readings";
const char* DEVICE_KEY = "YOUR_DEVICE_KEY";  // copy from the Devices tab

const int   SENSOR_PIN = 34;    // ADC pin
const int   RAW_DRY    = 3200;  // reading in air / fully dry
const int   RAW_WET    = 1300;  // reading in water / saturated

void setup() {
  Serial.begin(115200);
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); }
  Serial.println("\nWiFi connected");
}

void postReading(int raw, float moisture) {
  HTTPClient http;
  http.begin(ENDPOINT);                       // HTTPS
  http.addHeader("Content-Type", "application/json");

  String body = String("{\"device_key\":\"") + DEVICE_KEY +
                "\",\"moisture\":" + String(moisture, 2) +
                ",\"raw\":" + String(raw) + "}";

  int code = http.POST(body);
  Serial.printf("POST %d: %s\n", code, http.getString().c_str());
  http.end();
}

void loop() {
  int raw = analogRead(SENSOR_PIN);
  float moisture = (float)(RAW_DRY - raw) * 100.0 / (float)(RAW_DRY - RAW_WET);
  if (moisture < 0) moisture = 0;
  if (moisture > 100) moisture = 100;

  postReading(raw, moisture);
  delay(15UL * 60UL * 1000UL);   // every 15 minutes
}

Test it from a computer

curl -X POST https://project--670037ee-58ed-4aa3-9988-56cec5e1267e.lovable.app/api/public/readings \
  -H "Content-Type: application/json" \
  -d '{"device_key":"YOUR_DEVICE_KEY","moisture":6.4}'