Add 868MHz envs, fix MAC id, offset timesync

README.md

@@ -224,6 +224,8 @@ inline constexpr uint16_t EXPECTED_SENDER_IDS[NUM_SENDERS] = { 0xF19C };
 ## Build Environments
 - `lilygo-t3-v1-6-1`: production build
 - `lilygo-t3-v1-6-1-test`: test build with `ENABLE_TEST_MODE`
+- `lilygo-t3-v1-6-1-868`: production build for 868 MHz modules
+- `lilygo-t3-v1-6-1-868-test`: test build for 868 MHz modules
 
 ## Limits & Known Constraints
 - **Compression**: uses lightweight RLE (good for JSON but not optimal).

include/config.h

@@ -38,7 +38,10 @@ constexpr uint8_t PIN_OLED_CTRL = 14;
 constexpr uint8_t PIN_METER_RX = 34;
 
 // LoRa settings
-constexpr long LORA_FREQUENCY = 433E6;
+#ifndef LORA_FREQUENCY_HZ
+#define LORA_FREQUENCY_HZ 433E6
+#endif
+constexpr long LORA_FREQUENCY = LORA_FREQUENCY_HZ;
 constexpr uint8_t LORA_SPREADING_FACTOR = 12;
 constexpr long LORA_BANDWIDTH = 125E3;
 constexpr uint8_t LORA_CODING_RATE = 5;
@@ -52,7 +55,8 @@ constexpr uint32_t OLED_AUTO_OFF_MS = 10UL * 60UL * 1000UL;
 
 constexpr uint8_t NUM_SENDERS = 1;
 inline constexpr uint16_t EXPECTED_SENDER_IDS[NUM_SENDERS] = {
-  0xF19C
+  //0xF19C //433mhz sender
+  0x7EB4 //868mhz sender
 };
 
 DeviceRole detect_role();

platformio.ini

@@ -31,3 +31,30 @@ lib_deps =
   knolleary/PubSubClient@^2.8
 build_flags =
   -DENABLE_TEST_MODE
+
+[env:lilygo-t3-v1-6-1-868]
+platform = espressif32
+board = ttgo-lora32-v1
+framework = arduino
+lib_deps =
+  sandeepmistry/LoRa@^0.8.0
+  bblanchon/ArduinoJson@^6.21.5
+  adafruit/Adafruit SSD1306@^2.5.9
+  adafruit/Adafruit GFX Library@^1.11.9
+  knolleary/PubSubClient@^2.8
+build_flags =
+  -DLORA_FREQUENCY_HZ=868E6
+
+[env:lilygo-t3-v1-6-1-868-test]
+platform = espressif32
+board = ttgo-lora32-v1
+framework = arduino
+lib_deps =
+  sandeepmistry/LoRa@^0.8.0
+  bblanchon/ArduinoJson@^6.21.5
+  adafruit/Adafruit SSD1306@^2.5.9
+  adafruit/Adafruit GFX Library@^1.11.9
+  knolleary/PubSubClient@^2.8
+build_flags =
+  -DENABLE_TEST_MODE
+  -DLORA_FREQUENCY_HZ=868E6

src/data_model.cpp

@@ -1,9 +1,10 @@
 #include "data_model.h"
-#include <WiFi.h>
+#include <esp_mac.h>
 
 void init_device_ids(uint16_t &short_id, char *device_id, size_t device_id_len) {
   uint8_t mac[6] = {0};
-  WiFi.macAddress(mac);
+  // Read base MAC without needing WiFi to be started.
+  esp_read_mac(mac, ESP_MAC_WIFI_STA);
   short_id = (static_cast<uint16_t>(mac[4]) << 8) | mac[5];
   snprintf(device_id, device_id_len, "dd3-%04X", short_id);
 }

src/main.cpp

@@ -21,6 +21,7 @@ static SenderStatus g_sender_statuses[NUM_SENDERS];
 static bool g_ap_mode = false;
 static WifiMqttConfig g_cfg;
 static uint32_t g_last_timesync_ms = 0;
+static constexpr uint32_t TIME_SYNC_OFFSET_MS = 15000;
 
 static void init_sender_statuses() {
   for (uint8_t i = 0; i < NUM_SENDERS; ++i) {
@@ -124,6 +125,9 @@ static void sender_cycle() {
 }
 
 static void receiver_loop() {
+  if (g_last_timesync_ms == 0) {
+    g_last_timesync_ms = millis() - (TIME_SYNC_INTERVAL_SEC * 1000UL - TIME_SYNC_OFFSET_MS);
+  }
   LoraPacket pkt = {};
   if (lora_receive(pkt, 0) && pkt.protocol_version == PROTOCOL_VERSION && pkt.payload_type == PayloadType::MeterData) {
     uint8_t decompressed[256];

src/test_mode.cpp

@@ -16,6 +16,7 @@ static uint32_t g_last_test_ms = 0;
 static uint16_t g_test_code_counter = 1000;
 static uint32_t g_last_timesync_ms = 0;
 static constexpr uint32_t TEST_SEND_INTERVAL_MS = 30000;
+static constexpr uint32_t TEST_TIMESYNC_OFFSET_MS = 15000;
 
 void test_sender_loop(uint16_t short_id, const char *device_id) {
   LoraPacket rx = {};
@@ -76,6 +77,9 @@ void test_sender_loop(uint16_t short_id, const char *device_id) {
 }
 
 void test_receiver_loop(SenderStatus *statuses, uint8_t count, uint16_t self_short_id) {
+  if (g_last_timesync_ms == 0) {
+    g_last_timesync_ms = millis() - (TIME_SYNC_INTERVAL_SEC * 1000UL - TEST_TIMESYNC_OFFSET_MS);
+  }
   if (millis() - g_last_timesync_ms > TIME_SYNC_INTERVAL_SEC * 1000UL) {
     g_last_timesync_ms = millis();
     time_send_timesync(self_short_id);