Documentation

// PAM8406 Amplifier - Arduino Example (tone melody)
// D9 -> 1k -> INL, INL -> 100nF -> GND, speaker across +L/-L

const int audioPin = 9;

// Simple startup jingle: note frequency (Hz) and duration (ms)
const int melody[][2] = {
  {262, 200}, {330, 200}, {392, 200}, {523, 400},
  {392, 200}, {523, 600},
};

void setup() {
  Serial.begin(9600);
  Serial.println("Playing jingle on PAM8406...");
}

void loop() {
  for (unsigned int i = 0; i < sizeof(melody) / sizeof(melody[0]); i++) {
    tone(audioPin, melody[i][0]);
    delay(melody[i][1]);
    noTone(audioPin);
    delay(30);
  }
  delay(2000);
}

// PAM8406 Amplifier - ESP32 Example (DAC sine sweep)
// INL -> GPIO 25 (DAC1), input GND -> GND, VCC -> VIN(5V)

#include <math.h>

const int SAMPLES = 64;
uint8_t sine[SAMPLES];

void setup() {
  Serial.begin(115200);
  for (int i = 0; i < SAMPLES; i++) {
    sine[i] = 128 + 100 * sinf(2 * PI * i / SAMPLES);  // 8-bit sine
  }
  Serial.println("Sweeping 200 Hz - 2 kHz on DAC1...");
}

void playTone(float freq, int ms) {
  // per-sample delay in microseconds for the target frequency
  int us = (int)(1000000.0f / (freq * SAMPLES));
  long end = millis() + ms;
  int i = 0;
  while (millis() < end) {
    dacWrite(25, sine[i]);
    i = (i + 1) % SAMPLES;
    delayMicroseconds(us);
  }
}

void loop() {
  for (float f = 200; f <= 2000; f *= 1.12f) {
    playTone(f, 120);
  }
  dacWrite(25, 128);          // rest at midpoint = silence
  delay(1500);
}

#!/usr/bin/env python3
# PAM8406 Amplifier - Raspberry Pi Example
# Audio out (3.5mm or USB dongle) -> INL/INR/GND, VCC -> 5V
# Plays a test file and sweeps the system volume.
# Install: sudo apt install alsa-utils; put test.wav in the same folder

import subprocess
import time

def set_volume(percent):
    subprocess.run(
        ["amixer", "sset", "Master", "{}%".format(percent)],
        stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)

print("Sweeping volume up while playing test.wav...")
player = subprocess.Popen(["aplay", "test.wav"])

try:
    vol = 20
    while player.poll() is None:
        set_volume(vol)
        print("Volume: {}%".format(vol))
        vol = min(90, vol + 10)
        time.sleep(1)
    print("Done.")
except KeyboardInterrupt:
    player.terminate()
    print("Stopped by user")

# PAM8406 Amplifier - Pico MicroPython Example (PWM melody)
# GP15 -> 1k -> INL, INL -> 100nF -> GND, speaker across +L/-L

from machine import Pin, PWM
import time

spk = PWM(Pin(15))

MELODY = [
    (262, 200), (330, 200), (392, 200), (523, 400),
    (392, 200), (523, 600),
]

def play(freq, ms):
    spk.freq(freq)
    spk.duty_u16(32768)       # 50% duty = loudest square tone
    time.sleep_ms(ms)
    spk.duty_u16(0)           # silence between notes
    time.sleep_ms(30)

print("Playing jingle on PAM8406...")
while True:
    for freq, ms in MELODY:
        play(freq, ms)
    time.sleep(2)