Modified FiveTalk with GPS coordinates, Power has OLED display at outset

exercises/14_Power/README.md

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+# Exercise 14: Power (Charging + Visual)
+
+This exercise is intentionally narrow in scope:
+- Detect if a battery is present.
+- Detect if USB/VBUS power is present.
+- Determine if charging is needed.
+- Keep charging enabled through AXP2101 PMU settings.
+- Flash the PMU charge LED while charging.
+- If fully charged, leave LED off (do nothing).
+
+OLED behavior:
+- For the first 2 minutes after boot, OLED shows:
+  - `Exercise 14 Power`
+  - node name (`NODE_LABEL`)
+  - time (RTC/system time if available, else uptime)
+  - charging state and battery stats
+- After 2 minutes, it switches to a steady `Power Monitor` header while continuing live stats.
+
+## Meshtastic references used
+- `src/Power.cpp`
+  - charging detection path (`isCharging()`, `isVbusIn()`, battery checks)
+- `src/modules/StatusLEDModule.cpp`
+  - PMU charging LED control via `PMU->setChargingLedMode(...)`
+
+## Build and upload
+```bash
+cd /usr/local/src/microreticulum/microReticulumTbeam/exercises/14_Power
+pio run -e ed -t upload
+pio device monitor -b 115200
+```

exercises/14_Power/platformio.ini

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+; 20260220 Codex
+; Exercise 14_Power
+
+[platformio]
+default_envs = ed
+
+[env]
+platform = espressif32
+framework = arduino
+board = esp32-s3-devkitc-1
+monitor_speed = 115200
+lib_deps =
+  lewisxhe/XPowersLib@0.3.3
+  Wire
+  olikraus/U8g2@^2.36.4
+
+build_flags =
+  -I ../../shared/boards
+  -I ../../external/microReticulum_Firmware
+  -D BOARD_MODEL=BOARD_TBEAM_S_V1
+  -D OLED_SDA=17
+  -D OLED_SCL=18
+  -D OLED_ADDR=0x3C
+  -D ARDUINO_USB_MODE=1
+  -D ARDUINO_USB_CDC_ON_BOOT=1
+
+[env:amy]
+extends = env
+upload_port = /dev/ttytAMY
+monitor_port = /dev/ttytAMY
+build_flags =
+  ${env.build_flags}
+  -D NODE_LABEL=\"AMY\"
+
+[env:bob]
+extends = env
+upload_port = /dev/ttytBOB
+monitor_port = /dev/ttytBOB
+build_flags =
+  ${env.build_flags}
+  -D NODE_LABEL=\"BOB\"
+
+[env:cy]
+extends = env
+upload_port = /dev/ttytCY
+monitor_port = /dev/ttytCY
+build_flags =
+  ${env.build_flags}
+  -D NODE_LABEL=\"CY\"
+
+[env:dan]
+extends = env
+upload_port = /dev/ttytDAN
+monitor_port = /dev/ttytDAN
+build_flags =
+  ${env.build_flags}
+  -D NODE_LABEL=\"DAN\"
+
+[env:ed]
+extends = env
+upload_port = /dev/ttytED
+monitor_port = /dev/ttytED
+build_flags =
+  ${env.build_flags}
+  -D NODE_LABEL=\"ED\"

exercises/14_Power/src/main.cpp

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+// 20260220 Codex
+// Exercise 14: Power / Charging Visual Indicator
+
+#include <Arduino.h>
+#include <Wire.h>
+#include <U8g2lib.h>
+#include <XPowersLib.h>
+#include <time.h>
+
+#include "tbeam_supreme_adapter.h"
+
+#ifndef NODE_LABEL
+#define NODE_LABEL "POWER"
+#endif
+
+#ifndef OLED_SDA
+#define OLED_SDA 17
+#endif
+#ifndef OLED_SCL
+#define OLED_SCL 18
+#endif
+#ifndef OLED_ADDR
+#define OLED_ADDR 0x3C
+#endif
+
+static XPowersLibInterface *g_pmu = nullptr;
+static U8G2_SH1106_128X64_NONAME_F_HW_I2C g_oled(U8G2_R0, U8X8_PIN_NONE);
+
+static const uint32_t kBlinkIntervalMs = 500;
+static const uint32_t kStatusIntervalMs = 1000;
+static const uint32_t kSerialIntervalMs = 2000;
+static const uint32_t kStartupDisplayMs = 120000;
+
+static bool g_ledOn = false;
+static uint32_t g_lastBlinkMs = 0;
+static uint32_t g_lastStatusMs = 0;
+static uint32_t g_lastSerialMs = 0;
+static uint32_t g_bootMs = 0;
+
+static void oledShow(const char *l1,
+                     const char *l2 = nullptr,
+                     const char *l3 = nullptr,
+                     const char *l4 = nullptr,
+                     const char *l5 = nullptr)
+{
+  g_oled.clearBuffer();
+  g_oled.setFont(u8g2_font_5x8_tf);
+  if (l1) g_oled.drawUTF8(0, 12, l1);
+  if (l2) g_oled.drawUTF8(0, 24, l2);
+  if (l3) g_oled.drawUTF8(0, 36, l3);
+  if (l4) g_oled.drawUTF8(0, 48, l4);
+  if (l5) g_oled.drawUTF8(0, 60, l5);
+  g_oled.sendBuffer();
+}
+
+static void setChargeLed(bool on)
+{
+  if (!g_pmu) return;
+  g_pmu->setChargingLedMode(on ? XPOWERS_CHG_LED_ON : XPOWERS_CHG_LED_OFF);
+}
+
+static void setupChargingDefaults()
+{
+  if (!g_pmu) return;
+  g_pmu->setChargeTargetVoltage(XPOWERS_AXP2101_CHG_VOL_4V2);
+  g_pmu->setChargerConstantCurr(XPOWERS_AXP2101_CHG_CUR_500MA);
+}
+
+static const char *powerState(bool batteryPresent, bool usbPresent, bool fullyCharged, bool chargingNow)
+{
+  if (!batteryPresent) return "NO BATTERY";
+  if (!usbPresent) return "USB NOT PRESENT";
+  if (fullyCharged) return "FULL";
+  if (chargingNow) return "CHARGING";
+  return "IDLE";
+}
+
+static void formatDisplayTime(char *out, size_t outSize)
+{
+  const time_t now = time(nullptr);
+  if (now > 1700000000) {
+    struct tm tmNow;
+    localtime_r(&now, &tmNow);
+    snprintf(out, outSize, "Time: %02d:%02d:%02d", tmNow.tm_hour, tmNow.tm_min, tmNow.tm_sec);
+    return;
+  }
+
+  uint32_t sec = millis() / 1000;
+  uint32_t hh = sec / 3600;
+  uint32_t mm = (sec % 3600) / 60;
+  uint32_t ss = sec % 60;
+  snprintf(out, outSize, "Uptime: %02lu:%02lu:%02lu", (unsigned long)hh, (unsigned long)mm, (unsigned long)ss);
+}
+
+void setup()
+{
+  g_bootMs = millis();
+
+  Serial.begin(115200);
+  delay(1200);
+  Serial.println("Exercise 14_Power boot");
+
+  Wire.begin(OLED_SDA, OLED_SCL);
+  g_oled.setI2CAddress(OLED_ADDR << 1);
+  g_oled.begin();
+  oledShow("Exercise 14 Power", "Node: " NODE_LABEL, "Booting...");
+
+  if (!tbeam_supreme::initPmuForPeripherals(g_pmu, &Serial)) {
+    Serial.println("ERROR: PMU init failed");
+    oledShow("Exercise 14 Power", "Node: " NODE_LABEL, "PMU init FAILED");
+    return;
+  }
+
+  setupChargingDefaults();
+  setChargeLed(false);
+
+  Serial.println("PMU init OK");
+  oledShow("Exercise 14 Power", "Node: " NODE_LABEL, "PMU ready");
+}
+
+void loop()
+{
+  if (!g_pmu) {
+    delay(1000);
+    return;
+  }
+
+  const bool batteryPresent = g_pmu->isBatteryConnect();
+  const bool usbPresent = g_pmu->isVbusIn();
+  const bool chargingNow = g_pmu->isCharging();
+  const int battPercent = g_pmu->getBatteryPercent();
+  const float battV = g_pmu->getBattVoltage() / 1000.0f;
+
+  const bool fullyCharged = batteryPresent && battPercent >= 100;
+  const bool shouldCharge = batteryPresent && usbPresent && !fullyCharged;
+
+  if (shouldCharge) {
+    if (millis() - g_lastBlinkMs >= kBlinkIntervalMs) {
+      g_lastBlinkMs = millis();
+      g_ledOn = !g_ledOn;
+      setChargeLed(g_ledOn);
+    }
+  } else {
+    g_ledOn = false;
+    setChargeLed(false);
+  }
+
+  if (millis() - g_lastStatusMs >= kStatusIntervalMs) {
+    g_lastStatusMs = millis();
+
+    char l1[32];
+    char l2[32];
+    char l3[32];
+    char l4[32];
+    char l5[32];
+
+    const char *state = powerState(batteryPresent, usbPresent, fullyCharged, chargingNow);
+    const bool startupWindow = (millis() - g_bootMs) < kStartupDisplayMs;
+
+    if (startupWindow) {
+      snprintf(l1, sizeof(l1), "Exercise 14 Power");
+    } else {
+      snprintf(l1, sizeof(l1), "Power Monitor");
+    }
+
+    snprintf(l2, sizeof(l2), "Node: %s", NODE_LABEL);
+    formatDisplayTime(l3, sizeof(l3));
+    snprintf(l4, sizeof(l4), "State: %s", state);
+    if (battPercent >= 0) {
+      snprintf(l5, sizeof(l5), "VBAT:%.3fV  %d%%", battV, battPercent);
+    } else {
+      snprintf(l5, sizeof(l5), "VBAT:%.3fV  pct:?", battV);
+    }
+
+    oledShow(l1, l2, l3, l4, l5);
+  }
+
+  if (millis() - g_lastSerialMs >= kSerialIntervalMs) {
+    g_lastSerialMs = millis();
+    Serial.printf("node=%s usb=%u batt=%u charging=%u full=%u led=%u vbatt=%.3fV pct=%d\r\n",
+                  NODE_LABEL,
+                  usbPresent ? 1 : 0,
+                  batteryPresent ? 1 : 0,
+                  chargingNow ? 1 : 0,
+                  fullyCharged ? 1 : 0,
+                  g_ledOn ? 1 : 0,
+                  battV,
+                  battPercent);
+  }
+
+  delay(20);
+}