Initial commit

src/power_manager.cpp

@@ -0,0 +1,48 @@
+#include "power_manager.h"
+#include "config.h"
+#include <WiFi.h>
+#include <esp_wifi.h>
+#include <esp_bt.h>
+#include <esp_sleep.h>
+
+static constexpr float BATTERY_DIVIDER = 2.0f;
+static constexpr float BATTERY_CAL = 1.0f;
+static constexpr float ADC_REF_V = 3.3f;
+
+void power_sender_init() {
+  esp_wifi_stop();
+  btStop();
+  analogReadResolution(12);
+  pinMode(PIN_BAT_ADC, INPUT);
+}
+
+void power_receiver_init() {
+  analogReadResolution(12);
+  pinMode(PIN_BAT_ADC, INPUT);
+}
+
+void read_battery(MeterData &data) {
+  const int samples = 8;
+  uint32_t sum = 0;
+  for (int i = 0; i < samples; ++i) {
+    sum += analogRead(PIN_BAT_ADC);
+    delay(5);
+  }
+  float avg = static_cast<float>(sum) / samples;
+  float v = (avg / 4095.0f) * ADC_REF_V * BATTERY_DIVIDER * BATTERY_CAL;
+
+  data.battery_voltage_v = v;
+  float pct = (v - 3.0f) / (4.2f - 3.0f) * 100.0f;
+  if (pct < 0.0f) {
+    pct = 0.0f;
+  }
+  if (pct > 100.0f) {
+    pct = 100.0f;
+  }
+  data.battery_percent = static_cast<uint8_t>(pct + 0.5f);
+}
+
+void go_to_deep_sleep(uint32_t seconds) {
+  esp_sleep_enable_timer_wakeup(static_cast<uint64_t>(seconds) * 1000000ULL);
+  esp_deep_sleep_start();
+}