Adafruit RP2040 Prop-Maker Feather - Staser sound effect

This uses the Prop-Maker Feather'’s I2S audio amplifier to generate a sound effect, in this case a Gallifreyan Staser sound effect.

For testing purposes, the sound is triggered by the use of the Boot button on the board (the Boot button on the Prop-Maker Feather is connected to GPIO7 and named board.Button in CircuitPython)

For use as a prop, the trigger would be wired to the Button terminal and the Ground terminal shared with the NeoPixel.

Getting your sound effect.

The Prop-Maker Feather requires a PCM 16-bit Mono WAV files at a sample rate of 22KHz. This can be created using Audicity by following the Adafruit instructions.

Code

# Staser sound effect

import board

import digitalio

import time

import neopixel

import random

import audiocore

import audiobusio

import audiomixer

import pwmio

import keypad

keys = keypad.Keys((board.BUTTON,), value_when_pressed=False, pull=True)

# One of the features of the prop-maker is that the Neopixel

# (and the amplifier and the speaker) can be switched on and off

external_power = digitalio.DigitalInOut(board.EXTERNAL_POWER)

external_power.direction = digitalio.Direction.OUTPUT

external_power.value = True

audio = audiobusio.I2SOut(board.I2S_BIT_CLOCK, board.I2S_WORD_SELECT, board.I2S_DATA)

def play(filename, audio):

    # i2s playback

    wave_file = open(filename, "rb")

    wave = audiocore.WaveFile(wave_file)

    mixer = audiomixer.Mixer(voice_count=1, sample_rate=22050, channel_count=1,

                         bits_per_sample=16, samples_signed=True)

    audio.play(mixer)

    mixer.voice[0].play(wave, loop=False)

    mixer.voice[0].level = 0.5

    print("Fire")

    wave_file

while True:

    event = keys.events.get()

    # event will be None if nothing has happened.

    if event:

        if event.pressed:

            play("staser.wav",audio)

print("Done")

References

https://learn.adafruit.com/adafruit-rp2040-prop-maker-feather/overview

https://learn.adafruit.com/key-pad-matrix-scanning-in-circuitpython/keys-one-key-per-pin

https://learn.adafruit.com/microcontroller-compatible-audio-file-conversion

https://learn.adafruit.com/lightsaber-rp2040/code-the-lightsaber

Raspberry Pi sound not working on HDMI

By default the Raspberry Pi will channel sound through the HDMI connection to a suitable television/monitor.

Most of the time that will work automatically (if it thinks the television/monitor is not equipped with a speaker or speakers, it routes it through the headphone socket).

The key thing is the "sometime".

Some television/monitors do not appear to tell the Raspberry Pi they have a speaker. This may be due to the monitor, or due to the HDMI cable in use.

The easiest way of forcing the sound to be output via one of the channels is to right click on the loudspeaker icon. The drop down will show available audio output devices, the tick indicating the selected one. Make your choice there.

You can also use the command line:
amixer cset numid=3 2

The parameter 2 sets output to HDMI, 1 sets it to the headphone socket and 0 sets it to default.

It is also possible using the configuration screen and by editing the /boot/config.txt file. See the reference for details.

References:
https://www.raspberrypi.org/documentation/configuration/audio-config.md