Add ADC sampling method option (#8131)

Co-authored-by: Djordje Mandic <6750655+DjordjeMandic@users.noreply.github.com>

esphome/components/adc/__init__.py

@@ -36,6 +36,14 @@ ATTENUATION_MODES = {
     "auto": "auto",
 }
 
+sampling_mode = adc_ns.enum("SamplingMode", is_class=True)
+
+SAMPLING_MODES = {
+    "avg": sampling_mode.AVG,
+    "min": sampling_mode.MIN,
+    "max": sampling_mode.MAX,
+}
+
 adc1_channel_t = cg.global_ns.enum("adc1_channel_t")
 adc2_channel_t = cg.global_ns.enum("adc2_channel_t")
 

esphome/components/adc/adc_sensor.h

@@ -28,6 +28,21 @@ static const adc_atten_t ADC_ATTEN_DB_12_COMPAT = ADC_ATTEN_DB_11;
 #endif
 #endif  // USE_ESP32
 
+enum class SamplingMode : uint8_t { AVG = 0, MIN = 1, MAX = 2 };
+const LogString *sampling_mode_to_str(SamplingMode mode);
+
+class Aggregator {
+ public:
+  void add_sample(uint32_t value);
+  uint32_t aggregate();
+  Aggregator(SamplingMode mode);
+
+ protected:
+  SamplingMode mode_{SamplingMode::AVG};
+  uint32_t aggr_{0};
+  uint32_t samples_{0};
+};
+
 class ADCSensor : public sensor::Sensor, public PollingComponent, public voltage_sampler::VoltageSampler {
  public:
 #ifdef USE_ESP32
@@ -54,6 +69,7 @@ class ADCSensor : public sensor::Sensor, public PollingComponent, public voltage
   void set_pin(InternalGPIOPin *pin) { this->pin_ = pin; }
   void set_output_raw(bool output_raw) { this->output_raw_ = output_raw; }
   void set_sample_count(uint8_t sample_count);
+  void set_sampling_mode(SamplingMode sampling_mode);
   float sample() override;
 
 #ifdef USE_ESP8266
@@ -68,6 +84,7 @@ class ADCSensor : public sensor::Sensor, public PollingComponent, public voltage
   InternalGPIOPin *pin_;
   bool output_raw_{false};
   uint8_t sample_count_{1};
+  SamplingMode sampling_mode_{SamplingMode::AVG};
 
 #ifdef USE_RP2040
   bool is_temperature_{false};

esphome/components/adc/adc_sensor_common.cpp

@@ -6,6 +6,59 @@ namespace adc {
 
 static const char *const TAG = "adc.common";
 
+const LogString *sampling_mode_to_str(SamplingMode mode) {
+  switch (mode) {
+    case SamplingMode::AVG:
+      return LOG_STR("average");
+    case SamplingMode::MIN:
+      return LOG_STR("minimum");
+    case SamplingMode::MAX:
+      return LOG_STR("maximum");
+  }
+  return LOG_STR("unknown");
+}
+
+Aggregator::Aggregator(SamplingMode mode) {
+  this->mode_ = mode;
+  // set to max uint if mode is "min"
+  if (mode == SamplingMode::MIN) {
+    this->aggr_ = UINT32_MAX;
+  }
+}
+
+void Aggregator::add_sample(uint32_t value) {
+  this->samples_ += 1;
+
+  switch (this->mode_) {
+    case SamplingMode::AVG:
+      this->aggr_ += value;
+      break;
+
+    case SamplingMode::MIN:
+      if (value < this->aggr_) {
+        this->aggr_ = value;
+      }
+      break;
+
+    case SamplingMode::MAX:
+      if (value > this->aggr_) {
+        this->aggr_ = value;
+      }
+  }
+}
+
+uint32_t Aggregator::aggregate() {
+  if (this->mode_ == SamplingMode::AVG) {
+    if (this->samples_ == 0) {
+      return this->aggr_;
+    }
+
+    return (this->aggr_ + (this->samples_ >> 1)) / this->samples_;  // NOLINT(clang-analyzer-core.DivideZero)
+  }
+
+  return this->aggr_;
+}
+
 void ADCSensor::update() {
   float value_v = this->sample();
   ESP_LOGV(TAG, "'%s': Got voltage=%.4fV", this->get_name().c_str(), value_v);
@@ -18,6 +71,8 @@ void ADCSensor::set_sample_count(uint8_t sample_count) {
   }
 }
 
+void ADCSensor::set_sampling_mode(SamplingMode sampling_mode) { this->sampling_mode_ = sampling_mode; }
+
 float ADCSensor::get_setup_priority() const { return setup_priority::DATA; }
 
 }  // namespace adc

esphome/components/adc/adc_sensor_esp32.cpp

@@ -78,12 +78,14 @@ void ADCSensor::dump_config() {
     }
   }
   ESP_LOGCONFIG(TAG, "  Samples: %i", this->sample_count_);
+  ESP_LOGCONFIG(TAG, "  Sampling mode: %s", LOG_STR_ARG(sampling_mode_to_str(this->sampling_mode_)));
   LOG_UPDATE_INTERVAL(this);
 }
 
 float ADCSensor::sample() {
   if (!this->autorange_) {
-    uint32_t sum = 0;
+    auto aggr = Aggregator(this->sampling_mode_);
+
     for (uint8_t sample = 0; sample < this->sample_count_; sample++) {
       int raw = -1;
       if (this->channel1_ != ADC1_CHANNEL_MAX) {
@@ -94,13 +96,14 @@ float ADCSensor::sample() {
       if (raw == -1) {
         return NAN;
       }
-      sum += raw;
+
+      aggr.add_sample(raw);
     }
-    sum = (sum + (this->sample_count_ >> 1)) / this->sample_count_;  // NOLINT(clang-analyzer-core.DivideZero)
     if (this->output_raw_) {
-      return sum;
+      return aggr.aggregate();
     }
-    uint32_t mv = esp_adc_cal_raw_to_voltage(sum, &this->cal_characteristics_[(int32_t) this->attenuation_]);
+    uint32_t mv =
+        esp_adc_cal_raw_to_voltage(aggr.aggregate(), &this->cal_characteristics_[(int32_t) this->attenuation_]);
     return mv / 1000.0f;
   }
 

esphome/components/adc/adc_sensor_esp8266.cpp

@@ -31,23 +31,27 @@ void ADCSensor::dump_config() {
   LOG_PIN("  Pin: ", this->pin_);
 #endif  // USE_ADC_SENSOR_VCC
   ESP_LOGCONFIG(TAG, "  Samples: %i", this->sample_count_);
+  ESP_LOGCONFIG(TAG, "  Sampling mode: %s", LOG_STR_ARG(sampling_mode_to_str(this->sampling_mode_)));
   LOG_UPDATE_INTERVAL(this);
 }
 
 float ADCSensor::sample() {
-  uint32_t raw = 0;
+  auto aggr = Aggregator(this->sampling_mode_);
+
   for (uint8_t sample = 0; sample < this->sample_count_; sample++) {
+    uint32_t raw = 0;
 #ifdef USE_ADC_SENSOR_VCC
-    raw += ESP.getVcc();  // NOLINT(readability-static-accessed-through-instance)
+    raw = ESP.getVcc();  // NOLINT(readability-static-accessed-through-instance)
 #else
-    raw += analogRead(this->pin_->get_pin());  // NOLINT
+    raw = analogRead(this->pin_->get_pin());  // NOLINT
 #endif  // USE_ADC_SENSOR_VCC
+    aggr.add_sample(raw);
   }
-  raw = (raw + (this->sample_count_ >> 1)) / this->sample_count_;  // NOLINT(clang-analyzer-core.DivideZero)
+
   if (this->output_raw_) {
-    return raw;
+    return aggr.aggregate();
   }
-  return raw / 1024.0f;
+  return aggr.aggregate() / 1024.0f;
 }
 
 std::string ADCSensor::unique_id() { return get_mac_address() + "-adc"; }

esphome/components/adc/adc_sensor_libretiny.cpp

@@ -23,23 +23,28 @@ void ADCSensor::dump_config() {
   LOG_PIN("  Pin: ", this->pin_);
 #endif  // USE_ADC_SENSOR_VCC
   ESP_LOGCONFIG(TAG, "  Samples: %i", this->sample_count_);
+  ESP_LOGCONFIG(TAG, "  Sampling mode: %s", LOG_STR_ARG(sampling_mode_to_str(this->sampling_mode_)));
   LOG_UPDATE_INTERVAL(this);
 }
 
 float ADCSensor::sample() {
   uint32_t raw = 0;
+  auto aggr = Aggregator(this->sampling_mode_);
+
   if (this->output_raw_) {
     for (uint8_t sample = 0; sample < this->sample_count_; sample++) {
-      raw += analogRead(this->pin_->get_pin());  // NOLINT
+      raw = analogRead(this->pin_->get_pin());  // NOLINT
+      aggr.add_sample(raw);
     }
-    raw = (raw + (this->sample_count_ >> 1)) / this->sample_count_;  // NOLINT(clang-analyzer-core.DivideZero)
-    return raw;
+    return aggr.aggregate();
   }
+
   for (uint8_t sample = 0; sample < this->sample_count_; sample++) {
-    raw += analogReadVoltage(this->pin_->get_pin());  // NOLINT
+    raw = analogReadVoltage(this->pin_->get_pin());  // NOLINT
+    aggr.add_sample(raw);
   }
-  raw = (raw + (this->sample_count_ >> 1)) / this->sample_count_;  // NOLINT(clang-analyzer-core.DivideZero)
-  return raw / 1000.0f;
+
+  return aggr.aggregate() / 1000.0f;
 }
 
 }  // namespace adc

esphome/components/adc/adc_sensor_rp2040.cpp

@@ -34,24 +34,28 @@ void ADCSensor::dump_config() {
 #endif  // USE_ADC_SENSOR_VCC
   }
   ESP_LOGCONFIG(TAG, "  Samples: %i", this->sample_count_);
+  ESP_LOGCONFIG(TAG, "  Sampling mode: %s", LOG_STR_ARG(sampling_mode_to_str(this->sampling_mode_)));
   LOG_UPDATE_INTERVAL(this);
 }
 
 float ADCSensor::sample() {
+  uint32_t raw = 0;
+  auto aggr = Aggregator(this->sampling_mode_);
+
   if (this->is_temperature_) {
     adc_set_temp_sensor_enabled(true);
     delay(1);
     adc_select_input(4);
-    uint32_t raw = 0;
+
     for (uint8_t sample = 0; sample < this->sample_count_; sample++) {
-      raw += adc_read();
+      raw = adc_read();
+      aggr.add_sample(raw);
     }
-    raw = (raw + (this->sample_count_ >> 1)) / this->sample_count_;  // NOLINT(clang-analyzer-core.DivideZero)
     adc_set_temp_sensor_enabled(false);
     if (this->output_raw_) {
-      return raw;
+      return aggr.aggregate();
     }
-    return raw * 3.3f / 4096.0f;
+    return aggr.aggregate() * 3.3f / 4096.0f;
   }
 
   uint8_t pin = this->pin_->get_pin();
@@ -68,11 +72,10 @@ float ADCSensor::sample() {
   adc_gpio_init(pin);
   adc_select_input(pin - 26);
 
-  uint32_t raw = 0;
   for (uint8_t sample = 0; sample < this->sample_count_; sample++) {
-    raw += adc_read();
+    raw = adc_read();
+    aggr.add_sample(raw);
   }
-  raw = (raw + (this->sample_count_ >> 1)) / this->sample_count_;  // NOLINT(clang-analyzer-core.DivideZero)
 
 #ifdef CYW43_USES_VSYS_PIN
   if (pin == PICO_VSYS_PIN) {
@@ -81,10 +84,10 @@ float ADCSensor::sample() {
 #endif  // CYW43_USES_VSYS_PIN
 
   if (this->output_raw_) {
-    return raw;
+    return aggr.aggregate();
   }
   float coeff = pin == PICO_VSYS_PIN ? 3.0f : 1.0f;
-  return raw * 3.3f / 4096.0f * coeff;
+  return aggr.aggregate() * 3.3f / 4096.0f * coeff;
 }
 
 }  // namespace adc

esphome/components/adc/sensor.py

@@ -1,11 +1,9 @@
 import logging
 
 import esphome.codegen as cg
-import esphome.config_validation as cv
-import esphome.final_validate as fv
-from esphome.core import CORE
 from esphome.components import sensor, voltage_sampler
 from esphome.components.esp32 import get_esp32_variant
+import esphome.config_validation as cv
 from esphome.const import (
     CONF_ATTENUATION,
     CONF_ID,
@@ -17,10 +15,14 @@ from esphome.const import (
     STATE_CLASS_MEASUREMENT,
     UNIT_VOLT,
 )
+from esphome.core import CORE
+import esphome.final_validate as fv
+
 from . import (
     ATTENUATION_MODES,
     ESP32_VARIANT_ADC1_PIN_TO_CHANNEL,
     ESP32_VARIANT_ADC2_PIN_TO_CHANNEL,
+    SAMPLING_MODES,
     adc_ns,
     validate_adc_pin,
 )
@@ -30,9 +32,11 @@ _LOGGER = logging.getLogger(__name__)
 AUTO_LOAD = ["voltage_sampler"]
 
 CONF_SAMPLES = "samples"
+CONF_SAMPLING_MODE = "sampling_mode"
 
 
 _attenuation = cv.enum(ATTENUATION_MODES, lower=True)
+_sampling_mode = cv.enum(SAMPLING_MODES, lower=True)
 
 
 def validate_config(config):
@@ -88,6 +92,7 @@ CONFIG_SCHEMA = cv.All(
                 cv.only_on_esp32, _attenuation
             ),
             cv.Optional(CONF_SAMPLES, default=1): cv.int_range(min=1, max=255),
+            cv.Optional(CONF_SAMPLING_MODE, default="avg"): _sampling_mode,
         }
     )
     .extend(cv.polling_component_schema("60s")),
@@ -112,6 +117,7 @@ async def to_code(config):
 
     cg.add(var.set_output_raw(config[CONF_RAW]))
     cg.add(var.set_sample_count(config[CONF_SAMPLES]))
+    cg.add(var.set_sampling_mode(config[CONF_SAMPLING_MODE]))
 
     if attenuation := config.get(CONF_ATTENUATION):
         if attenuation == "auto":

tests/component_tests/sensor/test_sensor.yaml

@@ -10,5 +10,6 @@ sensor:
     pin: A0
     id: s_1
     name: test s1
+    sampling_mode: min
     update_interval: 60s
     device_class: voltage