From 9f76376a5cc7894cff9ca87bbdd34dab715d8a59 Mon Sep 17 00:00:00 2001
From: Dexif <evgeniy@spitsyn.net>
Date: Sun, 22 Feb 2026 11:13:36 +0200
Subject: [PATCH] feat: Update BatteryMonitor for Arduino ESP32 Core 3.x
 compatibility (#21)

Migrating to Arduino ESP32 Core 3.x (ESP-IDF 5.x). The esp_adc_cal_* API
was removed in ESP-IDF 5.x - replaced with analogReadMilliVolts() which
handles ADC calibration internally.

---------

Co-authored-by: Dave Allie <dave@daveallie.com>
---
 .../BatteryMonitor/include/BatteryMonitor.h   |  6 ---
 .../BatteryMonitor/src/BatteryMonitor.cpp     | 40 +++++++++----------
 2 files changed, 18 insertions(+), 28 deletions(-)

diff --git a/libs/hardware/BatteryMonitor/include/BatteryMonitor.h b/libs/hardware/BatteryMonitor/include/BatteryMonitor.h
index f5ae338..98741ce 100644
--- a/libs/hardware/BatteryMonitor/include/BatteryMonitor.h
+++ b/libs/hardware/BatteryMonitor/include/BatteryMonitor.h
@@ -12,18 +12,12 @@ public:
     // Read the battery voltage in millivolts (accounts for divider)
     uint16_t readMillivolts() const;
 
-    // Read raw millivolts from ADC (doesn't account for divider)
-    uint16_t readRawMillivolts() const;
-
     // Read the battery voltage in volts (accounts for divider)
     double readVolts() const;
 
     // Percentage (0-100) from a millivolt value
     static uint16_t percentageFromMillivolts(uint16_t millivolts);
 
-    // Calibrate a raw ADC reading and return millivolts
-    static uint16_t millivoltsFromRawAdc(uint16_t adc_raw);
-
 private:
     uint8_t _adcPin;
     float _dividerMultiplier;
diff --git a/libs/hardware/BatteryMonitor/src/BatteryMonitor.cpp b/libs/hardware/BatteryMonitor/src/BatteryMonitor.cpp
index 3604067..4786c59 100644
--- a/libs/hardware/BatteryMonitor/src/BatteryMonitor.cpp
+++ b/libs/hardware/BatteryMonitor/src/BatteryMonitor.cpp
@@ -1,9 +1,9 @@
 #include "BatteryMonitor.h"
-#include <esp32-hal-adc.h>
+#include <esp_idf_version.h>
+#include <Arduino.h>
+#if ESP_IDF_VERSION_MAJOR < 5
 #include <esp_adc_cal.h>
-
-inline float min(const float a, const float b) { return a < b ? a : b; }
-inline float max(const float a, const float b) { return a > b ? a : b; }
+#endif
 
 BatteryMonitor::BatteryMonitor(uint8_t adcPin, float dividerMultiplier)
   : _adcPin(adcPin), _dividerMultiplier(dividerMultiplier)
@@ -17,15 +17,18 @@ uint16_t BatteryMonitor::readPercentage() const
 
 uint16_t BatteryMonitor::readMillivolts() const
 {
-    const uint16_t raw = readRawMillivolts();
-    const uint32_t mv = millivoltsFromRawAdc(raw);
-    return static_cast<uint32_t>(mv * _dividerMultiplier);
-}
-
-uint16_t BatteryMonitor::readRawMillivolts() const
-{
+#if ESP_IDF_VERSION_MAJOR < 5
+    // ESP-IDF 4.x doesn't have analogReadMilliVolts, so we need to do the calibration manually
     const uint16_t raw = analogRead(_adcPin);
-    return raw;
+    esp_adc_cal_characteristics_t adc_chars;
+    esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_12, ADC_WIDTH_BIT_12, 1100, &adc_chars);
+    const uint16_t mv = esp_adc_cal_raw_to_voltage(raw, &adc_chars);
+#else
+    // ESP-IDF 5.x has analogReadMilliVolts
+    const uint16_t mv = analogReadMilliVolts(_adcPin);
+#endif
+
+    return static_cast<uint16_t>(mv * _dividerMultiplier);
 }
 
 double BatteryMonitor::readVolts() const
@@ -43,15 +46,8 @@ uint16_t BatteryMonitor::percentageFromMillivolts(uint16_t millivolts)
                7501.3202;
 
     // Clamp to [0,100] and round
-    y = max(y, 0.0);
-    y = min(y, 100.0);
+    y = std::max(y, 0.0);
+    y = std::min(y, 100.0);
     y = round(y);
-    return static_cast<int>(y);
-}
-
-uint16_t BatteryMonitor::millivoltsFromRawAdc(uint16_t adc_raw)
-{
-    esp_adc_cal_characteristics_t adc_chars;
-    esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_12, ADC_WIDTH_BIT_12, 1100, &adc_chars);
-    return esp_adc_cal_raw_to_voltage(adc_raw, &adc_chars);
+    return y;
 }