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libraries/audio-tools/examples/examples-stream/streams-generator-analog/README.md

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+# I2S Analog Output Test
+
+This is a simple basic test for the ESP32 __analog output__ using I2S.
+
+We just send a generated sine wave and expect to hear a clean signal.
+Please note the log level should be set to Warning so that there is no disturbing output!
+
+Make sure that you do not use any noisy power supply!
+
+### Output Device: Earphones
+
+You can also use some simple earphones
+
+![DAC](https://pschatzmann.github.io/Resources/img/earphones.jpg)
+
+On the ESP32 the stereo output is on the Pins GPIO25 and GPIO26
+
+| Earphone|  ESP32           | UNO R4  |
+| --------| -----------------|---------|
+| Left    |  GPIO25          | A0      |
+| Righ    |  GPIO25          | GND     |
+| GND     |  GND             | GND     |
+
+
+### Output Device: Piezo Electric Element
+
+To test the output I am using a piezo electric element
+
+![DAC](https://pschatzmann.github.io/Resources/img/piezo.jpeg)
+
+
+On the ESP32 the stereo output is on the Pins GPIO25 and GPIO26
+
+| PIEZO   |  ESP32           | UNO R4  |
+| --------| -----------------|---------|
+| +       |  GPIO25          | A0      |
+| -       |  GND             | GND     |
+
+

libraries/audio-tools/examples/examples-stream/streams-generator-analog/streams-generator-analog.ino

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+/**
+ * @file streams-generator-analog.ino
+ * @author Phil Schatzmann
+ * @brief see https://github.com/pschatzmann/arduino-audio-tools/blob/main/examples/examples-stream/streams-generator-analog/README.md 
+ * @author Phil Schatzmann
+ * @copyright GPLv3
+ **/
+ 
+#include "AudioTools.h"
+
+AudioInfo info(8000, 1, 16);
+SineWaveGenerator<int16_t> sineWave(32000);                // subclass of SoundGenerator with max amplitude of 32000
+GeneratedSoundStream<int16_t> sound(sineWave);             // Stream generated from sine wave
+AnalogAudioStream out; 
+StreamCopy copier(out, sound);                             // copies sound into i2s
+
+// Arduino Setup
+void setup(void) {  
+  // Open Serial 
+  Serial.begin(115200);
+  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Info);
+
+  // start the analog output
+  auto config = out.defaultConfig(TX_MODE);
+  config.copyFrom(info); 
+  out.begin(config);
+
+  // Setup sine wave
+  sineWave.begin(info, N_B4);
+  Serial.println("started...");
+}
+
+// Arduino loop - copy sound to out 
+void loop() {
+  copier.copy();
+}