Your Raspberry Pi computer is like an electronic brain - and with the Adafruit Voice Bonnet you can give it a mouth and ears as well! Featuring two microphones and two 1 Watt speaker outputs using a high quality I2S codec, this Pi add-on will work with any Raspberry Pi with a 2x20 connector - from the Pi Zero up to the Pi 4 and beyond (basically all but the very first ones made).

The on-board WM8960 codec uses I2S digital audio for great quality recording and playback - so it sounds a lot better than the headphone jack on the Pi (or the no-headphone jack on a Pi Zero). We put ferrite beads and filter capacitors on every input and output to get the best possible performance, and all at a great price.

We specifically designed this bonnet for use with making machine learning projects such as DIY voice assistants - for example see this guide on creating a DIY Google Assistant. But you could do various voice activated or voice recognition projects. With two microphones, basic voice position can be detected as well.

With the extra space on the PCB we also added some bonus extras!

No assembly required! Simply pop it onto your Pi and install the microphone/speaker card using our installer script. Your Pi will then have stereo input and output for use in any software - they appear as any other speaker/mic would. Play music or record audio with ease. For audio input, the two microphones are built into the Bonnet. For audio output, you can either use the Line-out/Headphone 3.5mm stereo jack or you can plug in one or two of our enclosed speakers. For DIY speakers, solder any 1W+ speaker to one of these JST 2-PH cables. If you'd like to stack another HAT or bonnet on top, use a 2x20 stacking header to feed through the 2x20 connector.

Power

  • 5.0V - Connected to power on the audio amp
  • 3.3V - Connected to the STEMMA QT / Qwiic connector
  • GND - Ground for everything

Sound

  • GPIO #18, GPIO#19, GPIO #20, GPIO #21 - I2S Digital Audio.
  • Speakers - The two speaker connectors are located on the bottom in the middle, labeled Right and Left. Plug in an enclosed speaker or  use a JST 2PH cable to attach custom speakers.
  • Microphones - The two mics are in the middle of each side, labeled L Mic and R Mic.
  • Headphones/Line Out - 3.5mm headphone jack located on the bottom right. Use any headphones or Line-Out to another audio system.
  • On/Off Switch - Located towards the left in the middle of the board, switches audio on and off.

Button

This pin has a 10K pullup to 3.3V so when the button is pressed, you will read a LOW voltage on this pin.

  • GPIO#17 - Button

STEMMA QT Connector

DotStar LEDs

Three fully color RGB addressable LEDs can provide feedback or a light show. Uses DotStar protocol (not NeoPixel) so any microcomputer can easily control the lights.

  • GPIO #5 - DotStar LED data pin.
  • GPIO #6 - Dotstar LED clock pin.

Digital/Analog Connector

GPIO#12 - 3-pin JST digital or analog connector. Easily connect things like NeoPixels or servos using this 2mm connector. You can also use a generic JST cable to connect to a breadboard.

OK now you have all your parts in order, it's time to get your Raspberry Pi computer set up with the HAT or Bonnet.

Step 1 - Burn SD Card

Use Etcher or the Raspberry Pi Imager to burn the latest Raspbian Lite to an SD card (you can use full but we won't be using the desktop software and it takes up a bunch of room.

Step 2 - Configure log-in access

You'll need to be able to log into your Pi, either enable SSH access (and use and Ethernet cable), use a USB to serial cable, or connect a monitor and keyboard. Basically get it so you can log in.

We have a quickstart guide here and here that you can follow, or there's dozens of online guides. it is assumed by the next step you are able to log in and type commands in - ideally from a desktop computer, so you can copy and paste in some of the very long commands!

Step 3 - Log in & Enable Internet

Once you've logged in, enable WiFi (if you have built in WiFi) with sudo raspi-config so you can ssh in.

Enable SSH as well if you haven't yet, also via sudo raspi-config

After you're done, reboot, and verify you can log into your Pi and that it has internet access by running ping -c 3 raspberrypi.org and seeing successful responses.

Step 4 - Update/Upgrade

Now that you are logged in, perform an update/update:

sudo apt update

sudo apt-get update

sudo apt-get -y upgrade

and

sudo apt-get install -y python3-pip

sudo pip3 install --upgrade setuptools

OK you've now got a nice, clean, connected, and up-to-date Pi!

Blinka is our CircuitPython library compatibility layer. It allows many of the libraries that were written for CircuitPython to run on CPython for Linux. To learn more about Blinka, you can check out our CircuitPython on Linux and Raspberry Pi guide.

We put together a script to easily make sure your Pi is correctly configured and install Blinka. It requires just a few commands to run. Most of it is installing the dependencies.

cd ~
sudo pip3 install --upgrade adafruit-python-shell
wget https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/raspi-blinka.py
sudo python3 raspi-blinka.py

When it asks you if you want to reboot, choose yes.

Finally, once it reboots, there are just a couple CircuitPython libraries to install for the BrainCraft HAT or Voice Bonnet.

The DotStar library is for controlling the 3 on-board DotStar LEDs and the Motor library is for testing out the GPIO pins.

pip3 install --upgrade adafruit-circuitpython-dotstar adafruit-circuitpython-motor adafruit-circuitpython-bmp280

That's it for Blinka and CircuitPython libraries.

Start by making sure you've installed I2C support, see the previous page (Blinka Setup) on how to do it!

Install Voicecard software

Make sure you've got the BrainCraft HAT or Voice Bonnet installed, and I2C support installed as well!

When you run sudo i2cdetect -y 1

you should see an entry under 1A, indicating the hardware sees the audio card. The number may also appear as UU if you already installed software

At the command line run:

Depending on your kernel version, you may need to change your branch. You can check your kernel version by typing uname -r.

If your kernel version is around 5.4, use the following:

  • git checkout v5.5
  • sudo ./install.sh

If your kernel version is 5.10 or higher, use the following:

  • git checkout v5.9
  • sudo ./install.sh

At the end you should see something like this:

Reboot with

sudo reboot

and on reboot run

sudo aplay -l

To list all sound cards, you should see it at the bottom

On a Raspberry Pi 4, your card number may be Card 2 instead of 1 because of the second HDMI port. You'll need to make some changes to some of the commands to reflect this further down.

If your card number differs from the above image, take note of your number.

You can use alsamixer to adjust the volume, dont forget to select the card with F6

A gain of about 60% is plenty loud!

Headphone/Speaker Test

Make sure the Audio On/Off switch is set to ON!

With either headphones plugged into the headphone jack or a speaker attached to the speaker port, run

speaker-test -c2

you will hear white noise coming out of the speakers/headphones!

If you don't hear anything, make sure you have the audio on/off switch set!

Microphone Test

There are two microphones, and now we can test that they work. This test is best done with headphones, not using the speaker port, because it can cause a painful feedback effect if the speakers are next to the mics!

Run:

sudo arecord -f cd -Dhw:1 | aplay -Dhw:1

If your sound card ID is not #1, then replace the number in both of the -Dhw: parameters with your actual number.

Then either gently rub each microphone, or speak to hear yourself echoed!

Control-C to quit when done

Your audio subsystem is now completely tested!

At this point, you should have just about everything already set up.

Besides the audio, the Voice Bonnet has quite a few other useful features on it that can be controlled through Python. We'll go through those and how to control them in Python.

Joystick and Button

The button uses simple digitalio, so it's really simple to control. Here's a little script that will setup the GPIO, create an internal pull up, and then print out the value to the terminal.

import time
import board
from digitalio import DigitalInOut, Direction, Pull

button = DigitalInOut(board.D17)
button.direction = Direction.INPUT
button.pull = Pull.UP

while True:
  if not button.value:
    print("Button pressed")
  time.sleep(0.01)

Go ahead and save the above code onto your Pi as button_test.py and run it with the following command:

python button_test.py

Now try moving the joystick and press the button and you should see it print out what you're pressing.

DotStar LEDs

The 3 DotStar LEDS can be controlled with the DotStar CircuitPython Library. Here's a little script that will setup the DotStar LEDs and then color cycle them.

import time
import board
import adafruit_dotstar

DOTSTAR_DATA = board.D5
DOTSTAR_CLOCK = board.D6

dots = adafruit_dotstar.DotStar(DOTSTAR_CLOCK, DOTSTAR_DATA, 3, brightness=0.2)

def wheel(pos):
    # Input a value 0 to 255 to get a color value.
    # The colours are a transition r - g - b - back to r.
    if pos < 0 or pos > 255:
        return (0, 0, 0)
    if pos < 85:
        return (255 - pos * 3, pos * 3, 0)
    if pos < 170:
        pos -= 85
        return (0, 255 - pos * 3, pos * 3)
    pos -= 170
    return (pos * 3, 0, 255 - pos * 3)

while True:
    for j in range(255):
        for i in range(3):
            rc_index = (i * 256 // 3) + j * 5
            dots[i] = wheel(rc_index & 255)
        dots.show()
        time.sleep(0.01)

Go ahead and save the above code onto your Pi as dotstar_test.py and run it with the following command:

python dotstar_test.py

The DotStar LEDs should start color-cycling in a rainbow.

GPIO JST connector

GPIO 12 is accessible with the JST connector on the bottom edge of the Voice Bonnet.

Parts

For this script, we'll just need one part that isn't included with the Voice Bonnet:

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Wiring

  • Connect the JST PH 3-pin plug into the GPIO #12 on the Voice Bonnet

Code

import time
import board
import pulseio
from adafruit_motor import servo

SERVO_PIN = board.D12
pwm = pulseio.PWMOut(SERVO_PIN, frequency=50)
servo = servo.Servo(pwm, min_pulse=750, max_pulse=2250)

while True:
    for angle in range(0, 180, 5):  # 0 - 180 degrees, 5 degrees at a time.
        servo.angle = angle
        time.sleep(0.05)
    for angle in range(180, 0, -5): # 180 - 0 degrees, 5 degrees at a time.
        servo.angle = angle
        time.sleep(0.05)

Go ahead and save the above code onto your Pi as servo_test.py and run it with the following command:

python servo_test.py

The servo should start sweeping back and forth in 5 degree increments.

Stemma QT

For the Stemma QT port, you can use any of our 50+ sensors, but we're going to use a script that demonstrates using the BMP280 because it's so simple.

Parts

For this script, we'll just need a BMP280 and a Stemma QT cable:

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Wiring

  • Connect one side of the Stemma QT cable to either port on the BMP280
  • Connect the other side to the Stemma QT port on the Voice Bonnet

Code

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

"""Simpletest Example that shows how to get temperature,
   pressure, and altitude readings from a BMP280"""
import time
import board

# import digitalio # For use with SPI
import busio
import adafruit_bmp280

# Create library object using our Bus I2C port
i2c = busio.I2C(board.SCL, board.SDA)
bmp280 = adafruit_bmp280.Adafruit_BMP280_I2C(i2c)

# OR create library object using our Bus SPI port
# spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
# bmp_cs = digitalio.DigitalInOut(board.D10)
# bmp280 = adafruit_bmp280.Adafruit_BMP280_SPI(spi, bmp_cs)

# change this to match the location's pressure (hPa) at sea level
bmp280.sea_level_pressure = 1013.25

while True:
    print("\nTemperature: %0.1f C" % bmp280.temperature)
    print("Pressure: %0.1f hPa" % bmp280.pressure)
    print("Altitude = %0.2f meters" % bmp280.altitude)
    time.sleep(2)

Go ahead and save the above code onto your Pi as bmp280_simpletest.py and run it with the following command:

python bmp280_simpletest.py

The terminal should start printing out the detected measurements.

This guide was first published on Oct 28, 2020. It was last updated on Oct 28, 2020.