feat(firmware): INA219 + voltage-divider auto-detect, power telemetry

TX firmware 2.0.4, RX firmware 2.2.0 (DevKit + C3 SuperMini).

Adds INA219 over I2C as Variant B alongside the existing voltage-
divider Variant A. Boot-time I2C probe at 0x40 auto-selects the mode;
NVS key 'pwr_mode_ovr' (auto/voltage/ina219/disabled) provides a
manual override accessible via the wifi_ota web UI dropdown.

TX:
  battery_monitor extended with power_init/read API (legacy
  battery_init/read preserved as wrappers). INA219 driver inlined:
  bus voltage from register 0x02, signed shunt current from 0x01,
  power computed as V*I in software (no calibration register).
  GPIO1=SDA, GPIO2=SCL, default I2C addr 0x40, 0.1 ohm shunt.

  LoRa packet format extended (forward-compatible):
    TANK:dist:pct:v:msgid:fwver:MODE:CURR:POW
  where MODE is one char (v/i/n), CURR is signed mA, POW is signed mW.
  Older RXs ignore the new optional fields.

  wifi_ota mode adds Power Sensor dropdown in SETTINGS card.
  /api/info returns power_override; /api/config accepts power_override.

RX (DevKit + C3, identical changes):
  lora_rx_packet_t and tx_data_t extended with power_mode, current_ma,
  power_mw, charging. Parser reads optional fields (defaults to '?'/0
  for older TX). /api/transmitters JSON exposes the new fields per TX.

  MQTT publishes 4 new HA-style sub-topics per TX:
    tanksync/<slug>/{power_mode,current_ma,power_mw,charging}
  Skipped when TX reports unknown mode (pre-2.0.4 firmware).

Author: Ravi Singh

firmware/receiver-c3/CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.16)
 
 # Version embedded in esp_app_desc_t — extracted by receiver for OTA display
-set(PROJECT_VER "2.1.0")
+set(PROJECT_VER "2.2.0")
 
 set(EXTRA_COMPONENT_DIRS "components")
 

firmware/receiver-c3/components/lora_rylr998/lora_rylr998.c

@@ -250,6 +250,36 @@ static bool parse_rcv(const char *line, lora_rx_packet_t *pkt) {
     } else {
         pkt->fw_version[0] = '\0';
     }
+
+    // Optional 7th field: power-monitor mode tag (single char) — absent for TX <v2.0.4
+    // Optional 8th field: signed current_ma (decimal integer)
+    // Optional 9th field: signed power_mw  (decimal integer)
+    pkt->power_mode = '?';
+    pkt->current_ma = 0;
+    pkt->power_mw   = 0;
+    pkt->charging   = false;
+
+    char *mode_s = strtok_r(NULL, ":\r\n", &sp2);
+    if (mode_s && mode_s[0] != '\0') {
+        char m = mode_s[0];
+        if (m == 'v' || m == 'V' || m == 'i' || m == 'I' || m == 'n' || m == 'N') {
+            pkt->power_mode = (char)((m >= 'A' && m <= 'Z') ? (m + 32) : m);
+        }
+    }
+
+    char *curr_s = strtok_r(NULL, ":\r\n", &sp2);
+    if (curr_s) {
+        pkt->current_ma = (int32_t)strtol(curr_s, NULL, 10);
+    }
+
+    char *pow_s = strtok_r(NULL, ":\r\n", &sp2);
+    if (pow_s) {
+        pkt->power_mw = (int32_t)strtol(pow_s, NULL, 10);
+    }
+
+    // Charging is true only if INA219 mode AND current is negative (current flowing into battery).
+    pkt->charging = (pkt->power_mode == 'i' && pkt->current_ma < 0);
+
     return true;
 }
 

firmware/receiver-c3/components/lora_rylr998/lora_rylr998.h

@@ -44,6 +44,14 @@ typedef struct {
     int      snr;               // Signal-to-noise ratio (dB)
     bool     data_valid;        // true if TANK packet parsed successfully
     char     fw_version[16];    // transmitter firmware version (empty if old TX)
+
+    // Power telemetry (since TX firmware v2.0.4) — present only if the TX
+    // packet includes the optional fields appended after fw_version.
+    // Old TX firmware that omits these → power_mode='?' and *_ma/*_mw=0.
+    char     power_mode;        // 'v'=voltage divider, 'i'=INA219, 'n'=disabled, '?'=unknown/old
+    int32_t  current_ma;        // signed; +ve discharge, -ve charge; 0 in voltage mode
+    int32_t  power_mw;          // V × I; 0 in voltage mode
+    bool     charging;          // explicit flag derived from current sign / unknown for old TX
 } lora_rx_packet_t;
 
 // ── Hardware state ────────────────────────────────────────────────────────────

firmware/receiver-c3/components/mqtt_client/mqtt_manager.c

@@ -235,6 +235,28 @@ void mqtt_publish_tank(int idx) {
 
     make_topic(topic, sizeof(topic), slug, "state");
     pub(topic, registry_state_str(data.state), 1);
+
+    // Power telemetry (TX v2.0.4+) — published only when TX has reported a real mode.
+    // '?' (unknown / pre-v2.0.4 TX) is skipped to avoid polluting topics for old hardware.
+    if (data.power_mode == 'v' || data.power_mode == 'i' || data.power_mode == 'n') {
+        const char *pmode_str = (data.power_mode == 'i') ? "ina219"
+                              : (data.power_mode == 'v') ? "voltage"
+                              : "none";
+        make_topic(topic, sizeof(topic), slug, "power_mode");
+        pub(topic, pmode_str, 1);
+
+        snprintf(val, sizeof(val), "%ld", (long)data.current_ma);
+        make_topic(topic, sizeof(topic), slug, "current_ma");
+        pub(topic, val, 1);
+
+        snprintf(val, sizeof(val), "%ld", (long)data.power_mw);
+        make_topic(topic, sizeof(topic), slug, "power_mw");
+        pub(topic, val, 1);
+
+        // HA-style binary sensor convention: ON / OFF
+        make_topic(topic, sizeof(topic), slug, "charging");
+        pub(topic, data.charging ? "ON" : "OFF", 1);
+    }
 }
 
 void mqtt_publish_system(void) {

firmware/receiver-c3/components/ota_manager/ota_manager.h

@@ -23,7 +23,7 @@
 
 // OTA configuration defaults
 #ifndef FIRMWARE_VERSION
-#define FIRMWARE_VERSION        "2.1.0"
+#define FIRMWARE_VERSION        "2.2.0"
 #endif
 #ifndef OTA_GITHUB_OWNER
 #define OTA_GITHUB_OWNER        "Techposts"
@@ -53,7 +53,7 @@ typedef enum {
 
 typedef struct {
     ota_status_t status;
-    char latest_version[32];    // e.g. "2.1.0" (from GitHub tag, strip "v" prefix)
+    char latest_version[32];    // e.g. "2.2.0" (from GitHub tag, strip "v" prefix)
     char download_url[256];
     int  progress_pct;          // 0-100 during download
     char error_msg[128];

firmware/receiver-c3/components/transmitter_registry/transmitter_registry.c

@@ -292,7 +292,8 @@ bool registry_set_enabled(uint16_t addr, bool enabled) {
 
 bool registry_update_data(uint16_t addr, int raw_dist, int bat_pct,
                            float bat_v, uint32_t msg_id, int rssi, int snr,
-                           const char *fw_version) {
+                           const char *fw_version,
+                           char power_mode, int32_t current_ma, int32_t power_mw) {
     LOCK();
     int idx = -1;
     for (int i = 0; i < s_count; i++) {
@@ -314,6 +315,11 @@ bool registry_update_data(uint16_t addr, int raw_dist, int bat_pct,
     s_data[idx].packets_rx++;
     s_data[idx].data_valid      = true;
     s_data[idx].state           = TX_STATE_CONNECTED;
+    s_data[idx].power_mode      = (power_mode == 'v' || power_mode == 'i' ||
+                                   power_mode == 'n') ? power_mode : '?';
+    s_data[idx].current_ma      = current_ma;
+    s_data[idx].power_mw        = power_mw;
+    s_data[idx].charging        = (s_data[idx].power_mode == 'i' && current_ma < 0);
     bool ver_changed = false;
     if (fw_version && fw_version[0]) {
         if (strcmp(s_data[idx].fw_version, fw_version) != 0) {

firmware/receiver-c3/components/transmitter_registry/transmitter_registry.h

@@ -58,6 +58,12 @@ typedef struct {
     bool      data_valid;
     tx_state_t state;
     char      fw_version[16];   // firmware version reported by transmitter
+
+    // Power telemetry (from TX firmware v2.0.4 onward)
+    char      power_mode;       // 'v'=voltage, 'i'=ina219, 'n'=disabled, '?'=unknown/old TX
+    int32_t   current_ma;       // signed; +ve = discharging, -ve = charging
+    int32_t   power_mw;         // V × I; 0 in voltage mode
+    bool      charging;         // true if INA219 reports negative current
 } tx_data_t;
 
 // ── Registry init ─────────────────────────────────────────────────────────────
@@ -97,9 +103,12 @@ void registry_persist(void);
 void registry_get_spiffs_info(size_t *total, size_t *used);
 
 // ── Data update ──────────────────────────────────────────────────────────────
+// `power_mode` is a single-char tag from the LoRa packet ('v'/'i'/'n'/'?').
+// `current_ma`/`power_mw` are 0 when TX is in voltage mode or absent (old TX).
 bool registry_update_data(uint16_t addr, int raw_dist, int bat_pct,
                            float bat_v, uint32_t msg_id, int rssi, int snr,
-                           const char *fw_version);
+                           const char *fw_version,
+                           char power_mode, int32_t current_ma, int32_t power_mw);
 
 // ── Queries ──────────────────────────────────────────────────────────────────
 int registry_count(void);

firmware/receiver-c3/components/web_server/web_server.c

@@ -532,6 +532,15 @@ static esp_err_t handle_api_data(httpd_req_t *req) {
         cJSON_AddNumberToObject(t, "battery_v", data.battery_voltage);
         cJSON_AddNumberToObject(t, "rssi", data.rssi);
         cJSON_AddStringToObject(t, "state", registry_state_str(data.state));
+        // Power telemetry (TX firmware v2.0.4+; '?' for older TX firmware)
+        const char *pmode_str = (data.power_mode == 'i') ? "ina219"
+                              : (data.power_mode == 'v') ? "voltage"
+                              : (data.power_mode == 'n') ? "none"
+                              : "unknown";
+        cJSON_AddStringToObject(t, "power_mode", pmode_str);
+        cJSON_AddNumberToObject(t, "current_ma", (double)data.current_ma);
+        cJSON_AddNumberToObject(t, "power_mw",   (double)data.power_mw);
+        cJSON_AddBoolToObject  (t, "charging",   data.charging);
         int64_t age_s = data.last_update_us > 0
             ? (esp_timer_get_time() - data.last_update_us) / 1000000LL : -1;
         cJSON_AddNumberToObject(t, "last_seen_s", (double)age_s);
@@ -664,6 +673,15 @@ static esp_err_t handle_get_transmitters(httpd_req_t *req) {
         cJSON_AddStringToObject(t, "fw_version", data.fw_version[0] ? data.fw_version : "unknown");
         cJSON_AddBoolToObject  (t, "ota_pending", ota_p);
         cJSON_AddNumberToObject(t, "ota_offset", ota_o);
+        // Power telemetry (TX firmware v2.0.4+; '?' for older TX firmware)
+        const char *pmode_str = (data.power_mode == 'i') ? "ina219"
+                              : (data.power_mode == 'v') ? "voltage"
+                              : (data.power_mode == 'n') ? "none"
+                              : "unknown";
+        cJSON_AddStringToObject(t, "power_mode", pmode_str);
+        cJSON_AddNumberToObject(t, "current_ma", (double)data.current_ma);
+        cJSON_AddNumberToObject(t, "power_mw",   (double)data.power_mw);
+        cJSON_AddBoolToObject  (t, "charging",   data.charging);
         cJSON_AddItemToArray(arr, t);
     }
     char *json = cJSON_PrintUnformatted(root); cJSON_Delete(root); send_json(req, json); free(json);

firmware/receiver-c3/components/web_server/web_server.h

@@ -36,7 +36,7 @@
 #define WEB_MAX_SOCKETS 5
 #endif
 #ifndef FIRMWARE_VERSION
-#define FIRMWARE_VERSION "2.1.0"
+#define FIRMWARE_VERSION "2.2.0"
 #endif
 #ifndef TANKSYNC_CLOUD_URL
 #define TANKSYNC_CLOUD_URL "https://your-tanksync-server.example.com"

firmware/receiver-c3/main/config.h

@@ -11,7 +11,7 @@
 // ============================================================================
 // FIRMWARE VERSION - update this on every release
 // ============================================================================
-#define FIRMWARE_VERSION        "2.1.0"
+#define FIRMWARE_VERSION        "2.2.0"
 #define FIRMWARE_TYPE           "receiver"
 
 // ============================================================================