EyeTrackVR · m-RNA · Jan 10, 2026
diff --git a/components/Monitoring/CMakeLists.txt b/components/Monitoring/CMakeLists.txt
@@ -9,14 +9,30 @@
 # +-----------------------+
 # |   ESP-IDF ADC HAL     | ← Espressif official driver
 # +-----------------------+
+#
+# Supported platforms (must support ESP-CAM):
+# - ESP32:    Tested
+# - ESP32-S3: Tested
+# - ESP32-S2: UNTESTED - Based on datasheet
 
 set(
   requires
   Helpers
 )
 
+# List of supported ADC platforms (aligned with ESP_CAMERA_SUPPORTED)
+set(ADC_SUPPORTED_TARGETS "esp32" "esp32s3" "esp32s2")
+
+# Check if current target supports ADC
+list(FIND ADC_SUPPORTED_TARGETS "$ENV{IDF_TARGET}" ADC_TARGET_INDEX)
+if (NOT ADC_TARGET_INDEX EQUAL -1)
+  set(ADC_SAMPLER_SUPPORTED TRUE)
+else()
+  set(ADC_SAMPLER_SUPPORTED FALSE)
+endif()
+
 # Platform-specific dependencies
-if ("$ENV{IDF_TARGET}" STREQUAL "esp32s3" OR "$ENV{IDF_TARGET}" STREQUAL "esp32")
+if (ADC_SAMPLER_SUPPORTED)
 list(APPEND requires
             driver 
             esp_adc
@@ -32,22 +48,20 @@ set(
 )
 
 # BSP Layer: ADC sampler implementation
-if ("$ENV{IDF_TARGET}" STREQUAL "esp32s3" OR "$ENV{IDF_TARGET}" STREQUAL "esp32")
-# Common ADC implementation
-list(APPEND source_files
-  "Monitoring/AdcSampler.cpp"
-  )
-
-# Platform-specific GPIO-to-channel mapping
-if ("$ENV{IDF_TARGET}" STREQUAL "esp32s3")
+if (ADC_SAMPLER_SUPPORTED)
+  # Common ADC implementation
   list(APPEND source_files
-    "Monitoring/AdcSampler_esp32s3.cpp"
+    "Monitoring/AdcSampler.cpp"
   )
-elseif ("$ENV{IDF_TARGET}" STREQUAL "esp32")
-  list(APPEND source_files
-    "Monitoring/AdcSampler_esp32.cpp"
-  )
-endif()
+
+  # Platform-specific GPIO-to-channel mapping and calibration
+  if ("$ENV{IDF_TARGET}" STREQUAL "esp32s3")
+    list(APPEND source_files "Monitoring/AdcSampler_esp32s3.cpp")
+  elseif ("$ENV{IDF_TARGET}" STREQUAL "esp32s2")
+    list(APPEND source_files "Monitoring/AdcSampler_esp32s2.cpp")
+  elseif ("$ENV{IDF_TARGET}" STREQUAL "esp32")
+    list(APPEND source_files "Monitoring/AdcSampler_esp32.cpp")
+  endif()
 endif()
 
 

diff --git a/components/Monitoring/Monitoring/AdcSampler.cpp b/components/Monitoring/Monitoring/AdcSampler.cpp
@@ -3,14 +3,15 @@
  * @brief BSP Layer - Common ADC sampling implementation
  *
  * This file contains platform-independent ADC sampling logic.
- * Platform-specific GPIO-to-channel mapping is in separate files:
- * - AdcSampler_esp32.cpp
- * - AdcSampler_esp32s3.cpp
+ * Platform-specific implementations are in separate files:
+ * - AdcSampler_esp32.cpp   (Tested)
+ * - AdcSampler_esp32s3.cpp (Tested)
+ * - AdcSampler_esp32s2.cpp (UNTESTED)
  */
 
 #include "AdcSampler.hpp"
 
-#if defined(CONFIG_IDF_TARGET_ESP32S3) || defined(CONFIG_IDF_TARGET_ESP32)
+#if ADC_SAMPLER_SUPPORTED
 #include <esp_log.h>
 
 static const char* TAG = "[AdcSampler]";
@@ -22,11 +23,7 @@ AdcSampler::~AdcSampler()
 {
     if (cali_handle_)
     {
-#if defined(CONFIG_IDF_TARGET_ESP32S3)
-        adc_cali_delete_scheme_curve_fitting(cali_handle_);
-#elif defined(CONFIG_IDF_TARGET_ESP32)
-        adc_cali_delete_scheme_line_fitting(cali_handle_);
-#endif
+        delete_calibration(cali_handle_);
         cali_handle_ = nullptr;
     }
 }
@@ -66,29 +63,8 @@ bool AdcSampler::init(int gpio, adc_atten_t atten, adc_bitwidth_t bitwidth, size
     }
 
     // Try calibration (requires eFuse data)
-    // ESP32-S3 uses curve-fitting, ESP32 uses line-fitting
-    esp_err_t cal_err = ESP_FAIL;
-
-#if defined(CONFIG_IDF_TARGET_ESP32S3)
-    // ESP32-S3 curve fitting calibration
-    adc_cali_curve_fitting_config_t cal_cfg = {
-        .unit_id = unit_,
-        .chan = channel_,
-        .atten = atten_,
-        .bitwidth = bitwidth_,
-    };
-    cal_err = adc_cali_create_scheme_curve_fitting(&cal_cfg, &cali_handle_);
-#elif defined(CONFIG_IDF_TARGET_ESP32)
-    // ESP32 line-fitting calibration is per-unit, not per-channel
-    adc_cali_line_fitting_config_t cal_cfg = {
-        .unit_id = unit_,
-        .atten = atten_,
-        .bitwidth = bitwidth_,
-    };
-    cal_err = adc_cali_create_scheme_line_fitting(&cal_cfg, &cali_handle_);
-#endif
-
-    if (cal_err == ESP_OK)
+    // Platform-specific: ESP32-S3/S2 use curve-fitting, ESP32 uses line-fitting
+    if (create_calibration(&cali_handle_))
     {
         cali_inited_ = true;
         ESP_LOGI(TAG, "ADC calibration initialized");
@@ -193,4 +169,4 @@ bool AdcSampler::configure_channel(int gpio, adc_atten_t atten, adc_bitwidth_t b
     return true;
 }
 
-#endif  // CONFIG_IDF_TARGET_ESP32S3 || CONFIG_IDF_TARGET_ESP32
+#endif  // ADC_SAMPLER_SUPPORTED
diff --git a/components/Monitoring/Monitoring/AdcSampler.hpp b/components/Monitoring/Monitoring/AdcSampler.hpp
@@ -20,7 +20,17 @@
 #include <cstdint>
 #include "sdkconfig.h"
 
-#if defined(CONFIG_IDF_TARGET_ESP32S3) || defined(CONFIG_IDF_TARGET_ESP32)
+// Supported ESP32 platforms with ADC1 oneshot driver
+// - ESP32: Tested
+// - ESP32-S3: Tested
+// - ESP32-S2: UNTESTED - GPIO mapping based on datasheet
+#if defined(CONFIG_IDF_TARGET_ESP32) || defined(CONFIG_IDF_TARGET_ESP32S3) || defined(CONFIG_IDF_TARGET_ESP32S2)
+#define ADC_SAMPLER_SUPPORTED 1
+#else
+#define ADC_SAMPLER_SUPPORTED 0
+#endif
+
+#if ADC_SAMPLER_SUPPORTED
 #include <vector>
 #include "esp_adc/adc_cali.h"
 #include "esp_adc/adc_cali_scheme.h"
@@ -86,10 +96,22 @@ class AdcSampler
 
     /**
      * @brief Platform-specific GPIO to ADC channel mapping
-     * @note Implemented separately in AdcSampler_esp32.cpp and AdcSampler_esp32s3.cpp
+     * @note Implemented in AdcSampler_esp32.cpp, AdcSampler_esp32s3 and AdcSampler_esp32s2.cpp
      */
     static bool map_gpio_to_channel(int gpio, adc_unit_t& unit, adc_channel_t& channel);
 
+    /**
+     * @brief Platform-specific ADC calibration initialization
+     * @note Implemented in AdcSampler_esp32.cpp, AdcSampler_esp32s3 and AdcSampler_esp32s2.cpp
+     */
+    bool create_calibration(adc_cali_handle_t* handle);
+
+    /**
+     * @brief Platform-specific ADC calibration cleanup
+     * @note Implemented in AdcSampler_esp32.cpp, AdcSampler_esp32s3 and AdcSampler_esp32s2.cpp
+     */
+    void delete_calibration(adc_cali_handle_t handle);
+
     // Shared ADC1 oneshot handle (single instance for all AdcSampler objects)
     static adc_oneshot_unit_handle_t shared_unit_;
 
@@ -109,7 +131,7 @@ class AdcSampler
     int filtered_mv_{0};
 };
 
-#else
+#else  // !ADC_SAMPLER_SUPPORTED
 // Stub for unsupported targets to keep interfaces consistent
 class AdcSampler
 {
@@ -131,4 +153,4 @@ class AdcSampler
         return false;
     }
 };
-#endif
+#endif  // ADC_SAMPLER_SUPPORTED
diff --git a/components/Monitoring/Monitoring/AdcSampler_esp32.cpp b/components/Monitoring/Monitoring/AdcSampler_esp32.cpp
@@ -1,6 +1,6 @@
 /**
  * @file AdcSampler_esp32.cpp
- * @brief BSP Layer - ESP32 specific GPIO to ADC channel mapping
+ * @brief BSP Layer - ESP32 specific ADC implementation
  *
  * ESP32 ADC1 GPIO mapping:
  * - GPIO32 → ADC1_CH4
@@ -56,4 +56,20 @@ bool AdcSampler::map_gpio_to_channel(int gpio, adc_unit_t& unit, adc_channel_t&
     }
 }
 
+bool AdcSampler::create_calibration(adc_cali_handle_t* handle)
+{
+    // ESP32 uses line fitting calibration (per-unit, not per-channel)
+    adc_cali_line_fitting_config_t cal_cfg = {
+        .unit_id = unit_,
+        .atten = atten_,
+        .bitwidth = bitwidth_,
+    };
+    return adc_cali_create_scheme_line_fitting(&cal_cfg, handle) == ESP_OK;
+}
+
+void AdcSampler::delete_calibration(adc_cali_handle_t handle)
+{
+    adc_cali_delete_scheme_line_fitting(handle);
+}
+
 #endif  // CONFIG_IDF_TARGET_ESP32
diff --git a/components/Monitoring/Monitoring/AdcSampler_esp32s2.cpp b/components/Monitoring/Monitoring/AdcSampler_esp32s2.cpp
@@ -0,0 +1,60 @@
+/**
+ * @file AdcSampler_esp32s2.cpp
+ * @brief BSP Layer - ESP32-S2 specific ADC implementation
+ *
+ *  UNTESTED - This implementation is based on ESP32-S2 datasheet.
+ *             Please verify on actual hardware before production use.
+ *
+ * ESP32-S2 ADC1 GPIO mapping:
+ * - GPIO1  → ADC1_CH0
+ * - GPIO2  → ADC1_CH1
+ * - GPIO3  → ADC1_CH2
+ * - GPIO4  → ADC1_CH3
+ * - GPIO5  → ADC1_CH4
+ * - GPIO6  → ADC1_CH5
+ * - GPIO7  → ADC1_CH6
+ * - GPIO8  → ADC1_CH7
+ * - GPIO9  → ADC1_CH8
+ * - GPIO10 → ADC1_CH9
+ *
+ * Note: ADC2 is not used to avoid conflicts with Wi-Fi.
+ *       Same as ESP32-S3 implementation.
+ */
+
+#include "AdcSampler.hpp"
+
+#if defined(CONFIG_IDF_TARGET_ESP32S2)
+
+bool AdcSampler::map_gpio_to_channel(int gpio, adc_unit_t& unit, adc_channel_t& channel)
+{
+    unit = ADC_UNIT_1;  // Only use ADC1 to avoid Wi-Fi conflict
+
+    // ESP32-S2: ADC1 on GPIO1–10 → CH0–CH9
+    if (gpio >= 1 && gpio <= 10)
+    {
+        channel = static_cast<adc_channel_t>(gpio - 1);
+        return true;
+    }
+
+    channel = ADC_CHANNEL_0;
+    return false;
+}
+
+bool AdcSampler::create_calibration(adc_cali_handle_t* handle)
+{
+    // ESP32-S2 uses curve fitting calibration
+    adc_cali_curve_fitting_config_t cal_cfg = {
+        .unit_id = unit_,
+        .chan = channel_,
+        .atten = atten_,
+        .bitwidth = bitwidth_,
+    };
+    return adc_cali_create_scheme_curve_fitting(&cal_cfg, handle) == ESP_OK;
+}
+
+void AdcSampler::delete_calibration(adc_cali_handle_t handle)
+{
+    adc_cali_delete_scheme_curve_fitting(handle);
+}
+
+#endif  // CONFIG_IDF_TARGET_ESP32S2
diff --git a/components/Monitoring/Monitoring/AdcSampler_esp32s3.cpp b/components/Monitoring/Monitoring/AdcSampler_esp32s3.cpp
@@ -1,6 +1,6 @@
 /**
  * @file AdcSampler_esp32s3.cpp
- * @brief BSP Layer - ESP32-S3 specific GPIO to ADC channel mapping
+ * @brief BSP Layer - ESP32-S3 specific ADC implementation
  *
  * ESP32-S3 ADC1 GPIO mapping:
  * - GPIO1  → ADC1_CH0
@@ -36,4 +36,21 @@ bool AdcSampler::map_gpio_to_channel(int gpio, adc_unit_t& unit, adc_channel_t&
     return false;
 }
 
+bool AdcSampler::create_calibration(adc_cali_handle_t* handle)
+{
+    // ESP32-S3 uses curve fitting calibration
+    adc_cali_curve_fitting_config_t cal_cfg = {
+        .unit_id = unit_,
+        .chan = channel_,
+        .atten = atten_,
+        .bitwidth = bitwidth_,
+    };
+    return adc_cali_create_scheme_curve_fitting(&cal_cfg, handle) == ESP_OK;
+}
+
+void AdcSampler::delete_calibration(adc_cali_handle_t handle)
+{
+    adc_cali_delete_scheme_curve_fitting(handle);
+}
+
 #endif  // CONFIG_IDF_TARGET_ESP32S3