From d7d71bf12fd28df817189ecda45f64410620e6f8 Mon Sep 17 00:00:00 2001
From: Adam Benhassen <adambenhassen@hotmail.com>
Date: Sun, 8 Mar 2026 01:37:01 +0100
Subject: [PATCH] feat: implement calibrated adc battery reading

---
 esp32_marauder/BatteryInterface.cpp | 19 +++++++++++++++++--
 esp32_marauder/BatteryInterface.h   |  1 +
 esp32_marauder/configs.h            |  5 +----
 3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/esp32_marauder/BatteryInterface.cpp b/esp32_marauder/BatteryInterface.cpp
index 6dc1863..3b53c29 100644
--- a/esp32_marauder/BatteryInterface.cpp
+++ b/esp32_marauder/BatteryInterface.cpp
@@ -26,7 +26,13 @@ void BatteryInterface::RunSetup() {
 
   #ifdef HAS_BATTERY
 
-    #ifndef HAS_AXP2101
+    #ifdef BATTERY_ADC_PIN
+      analogReadResolution(12);
+      pinMode(BATTERY_ADC_PIN, INPUT);
+      this->has_adc_battery = true;
+      this->i2c_supported = true;
+      Serial.println(F("Battery: ADC mode"));
+    #elif !defined(HAS_AXP2101)
       Wire.begin(I2C_SDA, I2C_SCL);
 
       Wire.beginTransmission(IP5306_ADDR);
@@ -59,13 +65,22 @@ void BatteryInterface::RunSetup() {
       this->i2c_supported = true;
       this->has_axp2101 = true;
     #endif
-    
+
     this->initTime = millis();
   #endif
 }
 
 int8_t BatteryInterface::getBatteryLevel() {
 
+  #ifdef BATTERY_ADC_PIN
+    if (this->has_adc_battery) {
+      int voltage_mv = analogReadMilliVolts(BATTERY_ADC_PIN) * 2; // voltage divider ratio 2:1
+      if (voltage_mv <= 3300) return 0;
+      if (voltage_mv >= 4150) return 100;
+      return (int8_t)(((voltage_mv - 3300) * 100) / 850);
+    }
+  #endif
+
   if (this->has_ip5306) {
     Wire.beginTransmission(IP5306_ADDR);
     Wire.write(0x78);
diff --git a/esp32_marauder/BatteryInterface.h b/esp32_marauder/BatteryInterface.h
index d5748c9..0d684c2 100644
--- a/esp32_marauder/BatteryInterface.h
+++ b/esp32_marauder/BatteryInterface.h
@@ -34,6 +34,7 @@ class BatteryInterface {
     bool has_max17048 = false;
     bool has_ip5306 = false;
     bool has_axp2101 = false;
+    bool has_adc_battery = false;
 
     BatteryInterface();
 
diff --git a/esp32_marauder/configs.h b/esp32_marauder/configs.h
index 7e3ba79..85f7fc4 100644
--- a/esp32_marauder/configs.h
+++ b/esp32_marauder/configs.h
@@ -138,6 +138,7 @@
     #define HAS_MINI_KB
     #ifdef MARAUDER_CARDPUTER_ADV
       #define HAS_BATTERY
+      #define BATTERY_ADC_PIN 10
     #endif
     #define HAS_BT
     #define HAS_BUTTONS
@@ -2673,10 +2674,6 @@
       #define I2C_SDA 5
     #endif
 
-    #ifdef MARAUDER_CARDPUTER_ADV
-      #define I2C_SDA 8
-      #define I2C_SCL 9
-    #endif
   #endif
 
   //// MARAUDER TITLE STUFF