87 lines
2.7 KiB
Arduino
87 lines
2.7 KiB
Arduino
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/*
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This example is only for ESP devices.
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This example demonstrates usage of integrated Digital to Analog Converter (DAC)
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You can display sound wave from audio device, or just measure voltage.
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To display audio prepare circuit found in following link or drafted as ASCII art
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https://forum.arduino.cc/index.php?topic=567581.0
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(!) Note that unlike in the link we are connecting the supply line to 3.3V (not 5V)
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because ADC can measure only up to around 3V. Anything above 3V will be very inaccurate.
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^ +3.3V
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_
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| |10k
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| | |10uF
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GPIO34-------------*------------| |----------- line in
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(Default ADC pin) | +| |
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_
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| |10k
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V GND
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Connect hot wire of your audio to Line in and GNd wire of audio cable to common ground (GND)
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Second option to measure voltage on trimmer / potentiometer has following connection
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^ +3.3V
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_
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GPIO34----------->| |
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(Default ADC pin) |_|
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_
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| | optional resistor
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V GND
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Optional resistor will decrease read value.
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Steps to run:
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1. Select target board:
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Tools -> Board -> ESP32 Arduino -> your board
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2. Upload sketch
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Press upload button (arrow in top left corner)
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When you see in console line like this: "Connecting........_____.....__"
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On your board press and hold Boot button and press EN button shortly. Now you can release both buttons.
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You should see lines like this: "Writing at 0x00010000... (12 %)" with rising percentage on each line.
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If this fails, try the board buttons right after pressing upload button, or reconnect the USB cable.
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3. Open plotter
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Tools -> Serial Plotter
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Enjoy
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Created by Tomas Pilny
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on 17th June 2021
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*/
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#include <I2S.h>
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void setup() {
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// Open serial communications and wait for port to open:
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// A baud rate of 115200 is used instead of 9600 for a faster data rate
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// on non-native USB ports
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Serial.begin(115200);
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while (!Serial) {
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; // wait for serial port to connect. Needed for native USB port only
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}
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// start I2S at 8 kHz with 32-bits per sample
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if (!I2S.begin(ADC_DAC_MODE, 8000, 16)) {
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Serial.println("Failed to initialize I2S!");
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while (1); // do nothing
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}
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}
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void loop() {
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// read a sample
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int sample = I2S.read();
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Serial.println(sample);
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}
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