Note* For now we are considering a low voltage range from 0-5volts. Which is properly supported by Arduino. To measure high Voltages, we have to add a resistance voltage divider network and change the code accordingly the values of resistance. Every thing is mentioned in the code given below.

Components required:

1) Arduino Nano

2) Pam8403 (Class D amplifier)

3) 100k Resistor

4) Speaker

5) 100nf capacitors

6) Breadboard and wires

Circuit diagram:

Circuit description:

We are using Arduino Nano in this project which is RISC AVR based 8-bit Microcontroller and here we are using talkie libraries to operate the audio functions. And a class D audio stereo 3W module(PAM8403) to amplify the signal for the speaker. There is a voltage in the digital pin of Arduino which is sensible by the code so a 100k- 1M (High value) resistor is used in parallel of the leads. There should be some voltage drop across the sensor so try to use a bigger value resistor.

Breadboard schematics:

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Code:

The code is separated in 3 different parts(2 supported files and one main file). You can Download full code for this project from HERE.

#include <Arduino.h>
#include <Talkie.h>
#include <TalkieUtils.h>
#include <Vocab_Special.h>

#if defined(__AVR__)

#include "ADCUtils.h" // for getVCCVoltage()

#elif defined(ARDUINO_ARCH_SAMD)

// On the Zero and others we switch explicitly to SerialUSB

#define Serial SerialUSB

#endif

#if defined(ESP32)

/*

 * Send serial info over Bluetooth

 * Use the Serial Bluetooth Terminal app and connect to ESP32_Talkie

 */

#include "BluetoothSerial.h"

BluetoothSerial SerialBT;

#define Serial SerialBT // redirect all Serial output to Bluetooth

#endif


/*

 * Voice PWM output pins for different ATmegas:

 *  ATmega328 (Uno and Nano): non inverted at pin 3, inverted at pin 11.

 *  ATmega2560: non inverted at pin 6, inverted at pin 7.

 *  ATmega32U4 (Leonardo): non inverted at pin 10, inverted at pin 9.

 *  ATmega32U4 (CircuitPlaygound): only non inverted at pin 5.

 *

 * As default both inverted and not inverted outputs...