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libraries/audio-tools/examples/examples-basic-api/base-adc-serial/README.md

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+# Stream Analog input to Serial  
+
+We can read an analog signal from a microphone and and write it out to Serial so that we can check the result in the __Arduino Serial Plotter__. To test the functionality I am using a MCP6022 microphone module.
+
+![MCP6022](https://pschatzmann.github.io/Resources/img/mcp6022.jpeg)
+![MCP6022](https://pschatzmann.github.io/Resources/img/mcp6022-1.jpeg)
+
+The MCP6022 is a anlog microphone which operates at 3.3 V
+We sample the sound signal with the help of the ESP32 I2S ADC input functionality.
+
+### Pins:
+ 
+| MCP6022 | ESP32
+|---------|---------------
+| VCC     | 3.3
+| GND     | GND
+| OUT     | GPIO34
+
+
+## Serial Plotter
+
+![Serial](https://pschatzmann.github.io/Resources/img/serial_plotter.png)
+
+
+

libraries/audio-tools/examples/examples-basic-api/base-adc-serial/base-adc-serial.ino

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+/**
+ * @file adc-serial.ino
+ * @author Phil Schatzmann
+ * @brief see https://github.com/pschatzmann/arduino-audio-tools/blob/main/examples/adc-serial/README.md
+ * 
+ * @author Phil Schatzmann
+ * @copyright GPLv3
+ * #TODO retest is outstanding
+ */
+ 
+#include "Arduino.h"
+#include "AudioTools.h"
+
+/**
+ * @brief We use a mcp6022 analog microphone on GPIO34 and write it to Serial
+ */ 
+
+AnalogAudioStream adc;
+const int32_t max_buffer_len = 1024;
+uint8_t buffer[max_buffer_len];
+// The data has a center of around 26427, so we we need to shift it down to bring the center to 0
+ConverterScaler<int16_t> scaler(1.0, -26427, 32700 );
+
+// Arduino Setup
+void setup(void) {
+
+  delay(3000); // wait for serial to become available
+
+  Serial.begin(115200);
+  // Include logging to serial
+  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Info); //Warning, Info, Error, Debug
+  Serial.println("starting ADC...");
+  auto adcConfig = adc.defaultConfig(RX_MODE);
+
+  // For ESP32 by Espressif Systems version 3.0.0 and later:
+  // see examples/README_ESP32.md
+  // adcConfig.sample_rate = 44100;
+  // adcConfig.adc_bit_width = 12;
+  // adcConfig.adc_calibration_active = true;
+  // adcConfig.is_auto_center_read = false;
+  // adcConfig.adc_attenuation = ADC_ATTEN_DB_12; 
+  // adcConfig.channels = 2;
+  // adcConfig.adc_channels[0] = ADC_CHANNEL_4; 
+  // adcConfig.adc_channels[1] = ADC_CHANNEL_5;
+
+  adc.begin(adcConfig);
+}
+
+// Arduino loop - repeated processing 
+void loop() {
+  size_t len = adc.readBytes(buffer, max_buffer_len); 
+  // move center to 0 and scale the values
+  scaler.convert(buffer, len);
+
+  int16_t *sample = (int16_t*) buffer; 
+  int size = len / 4;
+  for (int j=0; j<size; j++){
+    Serial.print(*sample++);
+    Serial.print(", ");
+    Serial.println(*sample++);
+  }
+}