Cup o' Sound - Adafruit Industries

Cup o' SoundCreated by Becky Stern

Last updated on 2021-10-22 11:08:31 AM EDT

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Guide Contents

Guide ContentsOverviewCircuit DiagramLoad Sound and Prepare ComponentsSolder Circuit and AssembleUse it!

© Adafruit Industries https://learn.adafruit.com/cup-o-sound Page 2 of 19

Overview

Bring the productive bustle of ambient coffee shop sounds with you anywhere by building a white noise

machine in a cup! This project uses the Adafruit Audio FX Board to play a 30 minute audio file on repeat.

The circuit is battery powered with the help of a lipoly backpack, which also allows for convenient

recharging over USB and the easy addition of a power switch. A speaker rests inside the lip of the cup,

driven by a class D audio amplifier using a 10K potentiometer for volume control.

The Cup o’ Sound requires no programming and is excellent for practicing your through-hole and free-

wire soldering skills. The result is a satisfyingly compact handful of portable sound that can be reused in

many contexts or rewired to act as a speaker alone.

Before you begin, familiarize yourself with the following guides:

Adafruit Guide to Excellent Soldering (https://adafru.it/drI)

Adafruit Audio FX Sound Board (https://adafru.it/e8Q)

Adafruit Pro Trinket LiPoly/LiIon Backpack (https://adafru.it/iPd)


For this project, you will need:

16MB Audio FX Board (https://adafru.it/2220)

half-size Perma-Proto board (https://adafru.it/dVr)

Adafruit Lipoly Backpack (https://adafru.it/e0A)

Adafruit Mono 2.5W Class D Audio Amplifier - PAM8302 (https://adafru.it/eyg)

lipoly battery (https://adafru.it/dcE)

speaker (https://adafru.it/eyh)

illuminated on/off button (https://adafru.it/eyi)

10K potentiometer (https://adafru.it/eyj)*

knob (https://adafru.it/eyk)

button quick-connect wires (https://adafru.it/eyi) (optional but handy)

stranded wire in various colors (https://adafru.it/egK)

paper coffee cup with lid

pliers and soldering tools

panavise (https://adafru.it/dDJ)

heat shrink tubing (https://adafru.it/dVd)

craft or utility knife

awl

pencil


http://www.adafruit.com/product/2220










https://www.adafruit.com/product/1970



*Yes, we realize this is a linear taper pot. If you've got a logarithmic one, feel free to use that!


Circuit Diagram

Click to enlarge.

The lipoly backpack sits atop the audio FX board with the provided headers. Other connections as

follows:

trigger pin 2 -> GND

potentiometer first leg -> GND

potentiometer second leg -> audio board R

potentiometer third leg -> amp A+

amp A- -> GND

amp Vin -> 5V

amp GND -> GND

switch leads to lipoly backpack (after cutting connecting trace)

switch LED + -> 220 ohm resistor -> 5V

switch LED - -> GND

amp outputs to speaker


Load Sound and Prepare Components

First thing's first-- load some sound on your Audio FX Board! We've formatted a mono OGG file containing

close to 30 minutes of coffee shop white noise:

https://adafru.it/eyl

Follow the Audio FX Board guide (https://adafru.it/e8Q) to transfer the sample file (or a file you make) to

your device.

Next it's time to breadboard the circuit. We highly recommend grabbing two audio boards and saving one

for breadboard prototyping. It saves a lot of time and frustration to work out a circuit on a solderless

breadboard before soldering your components together. Ask us how we know!

Solder the headers and screw terminals onto your amp, and solder wires onto your speaker:

https://adafru.it/eyl


http://blog.adafruit.com/wp-content/uploads/2015/02/T02HOLDL.ogg

On the lipoly backpack, cut the trace connecting the

switch pads, and solder two quick-connect wires in place.

While you're there, add a solder bridge to convert the

charger to 500mA where marked.


https://learn.adafruit.com//assets/23281


Since the switch has to be installed from the outside of the cup, it'll be hard to connect wires to it inside

the cup. That's where these arcade button quick-connects come in handy! See how they tightly grip the

pins without any soldering? Cool. Take a good look now, since we can't quite get our camera lens inside

the cup to see them later:


Solder the lipoly backpack to the audio board with the included long headers. Trim the rest of your

headers and solder them in place on the audio board. See how the lipoly backpack headers come up

short on the underside? You may want to insert the headers from underneath the audio board if you want

them to be the same depth as the others (for inserting into a solderless breadboard). This was the second

board we assembled for this project, and in prep for the final circuit the header depth descrepency wasn't

a problem.


After prototyping, remove the potentiometer from the

solderless breadboard and solder on three wires (with

heat shrink tubing) to prepare for installing in the coffee

cup.




Solder Circuit and Assemble

Position the audio board with the USB port at the edge of the Perma-Proto. Solder the leads in place:

Next add the amp as shown, and solder up the rest of the components according to the circuit diagram.

Remember to use quick-connect wires for the LED inside the pushbutton.



Mark and cut a hole for the on/off switch at the base of

the cup. Remove the switch's screw-ring and install the

switch, reattaching the screw-ring on the inside.





Likewise make a hole for the volume adjustment knob at

the side of the cup. The potentiometer attaches from the

inside with a washer and nut on the outside, and the

knob slips over from the outside.





Use a pair of pliers to bend the flanges on the speaker to achieve a good fit inside the coffee cup.

Attach the quick connect wires to the power switch and click it on! Be sure your circuit is working properly

before packing it all up inside the cup:



Use it!

Enjoy your new ambient bliss. Power up and get cracking on your novel, or code up that new hot app!

You can optionally cut a hole in the base of the cup for USB recharging. Battery life will vary based on

audio content and volume.


© Adafruit Industries Last Updated: 2021-10-22 11:08:31 AM EDT Page 19 of 19

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Cup o' Sound - Adafruit Industries