تصميم شبكة الحساسات اللاسلكية وإدارة العقد

#include <WiFi.h>
#include <time.h>

void syncTime() {
  configTzTime("EET-2EEST,M4.5.5/0,M10.5.4/24", "pool.ntp.org", "time.google.com"); // Africa/Cairo
  struct tm t;
  if (getLocalTime(&t, 10000)) {
    char buf[25];
    strftime(buf, sizeof(buf), "%Y-%m-%dT%H:%M:%S", &t);   // ISO-8601 -> same format the server expects
    Serial.printf("time synced: %s\n", buf);
  } else {
    Serial.println("NTP failed - server will timestamp on arrival");
  }
}

سلسلة المنطقة الزمنية POSIX لمصر تتضمن التوقيت الصيفي. إن تغيرت قواعده يكفي تعديل هذا السطر — أو اترك السيرفر يضع الوقت.

/*
  Session 6 — ESP-NOW sensor node (star topology, no router needed in the field)
  Sends a struct to the gateway every 60 s; retries 3 times if the delivery callback reports failure.
  Set GATEWAY_MAC to the MAC printed by s06_espnow_gateway. Use the SAME Wi-Fi channel as the gateway.
  Compatible with ESP32 Arduino core 3.x (esp_now_send_cb_t uses wifi_tx_info_t). For core 2.x change the
  callback signature to:  void onSent(const uint8_t *mac, esp_now_send_status_t status)
*/
#include <WiFi.h>
#include <esp_now.h>
#include <esp_wifi.h>
#include <DHT.h>

uint8_t GATEWAY_MAC[] = {0x24, 0x6F, 0x28, 0xAA, 0xBB, 0xCC};   // <-- edit
const uint8_t CHANNEL = 6;
const uint8_t NODE_NUM = 2;                                     // 1..20, unique per node

typedef struct __attribute__((packed)) {
  uint8_t node;
  uint32_t seq;
  float temp;
  float hum;
  uint16_t soilRaw;
  float battery;
} Reading;

DHT dht(4, DHT22);
Reading msg;
volatile bool lastOk = false;

void onSent(const wifi_tx_info_t *info, esp_now_send_status_t status) { lastOk = (status == ESP_NOW_SEND_SUCCESS); }

void setup() {
  Serial.begin(115200);
  dht.begin();
  WiFi.mode(WIFI_STA);
  esp_wifi_set_channel(CHANNEL, WIFI_SECOND_CHAN_NONE);
  if (esp_now_init() != ESP_OK) { Serial.println("ESP-NOW init failed"); ESP.restart(); }
  esp_now_register_send_cb(onSent);
  esp_now_peer_info_t peer = {};
  memcpy(peer.peer_addr, GATEWAY_MAC, 6);
  peer.channel = CHANNEL;
  esp_now_add_peer(&peer);
  Serial.print("node MAC: "); Serial.println(WiFi.macAddress());
}

void loop() {
  msg.node = NODE_NUM;
  msg.seq++;
  msg.temp = dht.readTemperature();
  msg.hum = dht.readHumidity();
  msg.soilRaw = analogRead(34);
  msg.battery = analogReadMilliVolts(33) * 2 / 1000.0;
  for (int attempt = 1; attempt <= 3; attempt++) {     // handle temporary loss
    lastOk = false;
    esp_now_send(GATEWAY_MAC, (uint8_t *)&msg, sizeof(msg));
    delay(60);
    if (lastOk) break;
    Serial.printf("seq %lu attempt %d failed\n", msg.seq, attempt);
    delay(200 * attempt);                                  // back-off
  }
  Serial.printf("seq %lu sent=%s\n", msg.seq, lastOk ? "OK" : "LOST");
  delay(60000);
}

/*
  Session 6 — ESP-NOW gateway (center of the star) — receives all field nodes and prints JSON lines.
  Connect it by USB to the farm laptop:  python serial_to_api.py  forwards each line to the Flask API,
  or extend it to publish over MQTT (session 7). Detects lost packets with the sequence number and
  marks a node offline when nothing arrives for 3 minutes.
  ESP32 Arduino core 3.x callback signature (core 2.x: void onRecv(const uint8_t *mac, const uint8_t *data, int len)).
*/
#include <WiFi.h>
#include <esp_now.h>
#include <esp_wifi.h>

const uint8_t CHANNEL = 6;
typedef struct __attribute__((packed)) {
  uint8_t node; uint32_t seq; float temp; float hum; uint16_t soilRaw; float battery;
} Reading;

uint32_t lastSeq[21] = {0};
unsigned long lastSeen[21] = {0};
uint32_t lost[21] = {0};

void onRecv(const esp_now_recv_info_t *info, const uint8_t *data, int len) {
  if (len != sizeof(Reading)) return;
  Reading r; memcpy(&r, data, sizeof(r));
  if (r.node > 20) return;
  if (lastSeq[r.node] && r.seq > lastSeq[r.node] + 1) lost[r.node] += r.seq - lastSeq[r.node] - 1;
  lastSeq[r.node] = r.seq;
  lastSeen[r.node] = millis();
  Serial.printf("{\"node_id\":\"node_%02d\",\"seq\":%lu,\"air_temp_c\":%.1f,\"air_humidity_pct\":%.1f,"
                "\"soil_raw\":%u,\"battery_v\":%.2f,\"rssi\":%d,\"lost\":%lu}\n",
                r.node, r.seq, r.temp, r.hum, r.soilRaw, r.battery, info->rx_ctrl->rssi, lost[r.node]);
}

void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);
  esp_wifi_set_channel(CHANNEL, WIFI_SECOND_CHAN_NONE);
  esp_now_init();
  esp_now_register_recv_cb(onRecv);
  Serial.print("# gateway MAC (copy into the nodes): "); Serial.println(WiFi.macAddress());
}

void loop() {
  static unsigned long check = 0;
  if (millis() - check > 30000) {
    check = millis();
    for (int n = 1; n <= 20; n++)
      if (lastSeen[n] && millis() - lastSeen[n] > 180000) Serial.printf("# node_%02d OFFLINE\n", n);
  }
}

__attribute__((packed)) يمنع المترجم من إضافة فراغات داخل الـ struct، فيكون حجمها متطابقاً بين العقدة والبوابة — بدونها قد تُقرأ القيم خطأ.