Kit Review – adafruit industries waveshield kit

Hello readers

Today we are going introduce another useful kit from adafruit industries – their waveshild Arduino shield kit. The purpose of this shield is to play audio files sourced from a computer, at the request of an Arduino sketch. It is an interesting product in that it meets one of the needs of the original concept of Arduino, that is:

… It’s intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments. (

Yes – yes indeed. For a while I had seen this kit, and though that there wasn’t much point to it. But if you spend a few moments contemplating how the control of sounds or recorded voice could be used, suddenly you have a “light bulb moment” and come up with all sorts of things, both crazy and sensible.  Once again, this kit arrives in typical adafruit packaging, a simple reusable antistatic bag:


and emptying the contents onto the desk reveals the following:


And before anyone asks me, no the parts don’t arrange themselves as they fall out of the bag. If they did, we’d have some much larger problems in the world. At first glance I was worried that not all of the parts had been included, however this is kit version 1.1, and there will be empty spaces on the PCB. Speaking of which, once again it is a nice thick, solder-masked and nicely silk screened PCB.

The pre-assembly checklist, assembly instructions and all other documentation and required software links can be found on the adafruit website. After checking off the included parts against the adafruit bill of materials, it was time to start. You will need a few extra things, for example a speaker if necessary, an SD memory card (up to one gigabyte in size) – and in my case two 8-pin IC sockets. When you live in an area where finding specialised ICs is difficult or just time-consuming, IC sockets are very cheap insurance.

The first item to solder in is the SD card, and this is a surface-mount part. But don’t let that worry you, it ‘clicks’ into the PCB, and you then just hold it down with one hand while holding some solder, and with the other hand heat each pad for two seconds and let some solder flow over the pads:


And you don’t need to solder in the last three, narrower contacts of the reader – they are not used. Everything else is standard through hole, nothing much to worry about apart from burning yourself while listening to the radio. Except for one resistor, R6 – the one next to IC4. If you solder in the resistor first, even though it sits normally – it is about one millimetre too close to the IC. So if you are going to assemble this, solder in IC4 before R6:


However it isn’t anything to panic about, just something to keep an eye out for. Moving forward, everything else went in easily:


The last basic soldering to take care of is the expansion pins for the shield to able to mate with other shields. The easiest way to solder these in is to first drop the new pins into an existing, matching board – as such:


Then drop the waveshield on top of the pins and solder away:


And finally, some links from the circuit to the digital pins… Then lo and behold, we’re finished:


During the initial testing and experimenting, I was going to use a set of earphones to listen to the output, however instead ended up installing a small 0.25 watt 8 ohm speaker. The solder pads for the speaker are between the rear of the headphone socket and C9. If you decide to use both headphones and a speaker, the circuit is designed in such a way as the headphone socket will cut off the speaker when headphones are in use. adafruit also sell the waveshield party pack which includes a memory card and speaker to save you shopping around.

Note that this shield will need digital pins 2~5 and 10~13 – as noted in Jon Oxer’s new website –

Now that the hardware has been taken care of, let’s get our Arduino talking and grooving. The first thing to do is install the wavehc library into your Arduino IDE software. The library and related buffering use a fair amount of memory, so if you are running an Arduino with the old ‘168 MCU, it’s time to find the $6 and upgrade to the ATmega328.

Next, visit the tronixstuff file repository. Download the waveshieldtest.pde sketch; and also download this audio file onto the SD card. Finally, insert the SD card, upload the sketch, insert your headphones and the board should play the file. Don’t forget to turn the volume up a little, yours may be set to off by default.

Now that we know it is working, it is time to examine how we can control things in more detail. The most important thing is to have your .wav sound files in the correct format. The maximum sampling rate is 22 kHz, depth of 16-bit, and in mono PCM format. You can download an open-source audio editor package to do the conversions for you here. ladyada has also written a good conversion tutorial for you here.

Apart from converting audio files for playback, if you want to get some backchat you will need to find a speech-synthesiser. You can make use of the AT+T Labs Natural Voices (R) Text to Speech demo website for this. Just enter some text, and then you can download the .wav file:


Now let’s have a quick look at how we can play files on demand, to let our own projects make some noise. Please download the sketch waveshieldtest2.pde. Although there is a large amount of code in there, what we’re interested in is just the void loop(); function. To play a .wav file, such as “wisdom.wav”, just use

So you can just mash that sketch and your own code together to get some files playing, however don’t forget your attributions to the original authors. Here is a … longer demonstration of waveshieldtest2.pde:

You can purchase the waveshield kit directly from adafruit industries.  High resolution images are available on flickr.

As always, thank you for reading and I look forward to your comments and so on. Furthermore, don’t be shy in pointing out errors or places that could use improvement. Please subscribe using one of the methods at the top-right of this web page to receive updates on new posts. Or join our Google Group.

[Note – The kit was purchased by myself personally and reviewed without notifying the manufacturer or retailer]

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John Boxall

Person. Founder and original author for VK3FJBX

11 thoughts on “Kit Review – adafruit industries waveshield kit

  1. Marcel

    I’ve had one of these for aaaaages.

    My project is a music jukebox for my wife’s toddler group. I put it all together when I first got the waveshield kit but came to ground when I realised that I needed more pins on the Arduino for more selection buttons — she needs something like 16 buttons so the project got shelved. (well, kinda. It actually became an 8 button controller for a jukebox app written in Director and running on an old Mac laptop)

    Until now! The game is back on since I’ve been getting into shiftIN and shiftOUT chips that allow me multiples of 8 buttons and 8 LEDs off just three Arduino pins! (as you know).

    Presently I’m sourcing buttons. Nice big buttons with LEDs built in cost a fortune so I’m trying to look for salvage options. An old Sony video switcher turned up at our scrap yard yesterday – the buttons are great but there’s only 8 of them plus red and green ones for on/off. I could do a sort of ‘two banks of eight’ arrangement but that’s not as immediate as 16 ready to go buttons. The search continues.


    1. John Boxall

      Hi Marcel
      Good on you for re-using the old Sony gear. I must admit sometimes it us just easier tp use the Mega when the extra i/o is needed, but I feel like a cheat when thinking that way!
      Your shiftIN/shiftOUT solution is a winner though. Nice one.
      enjoy the weekend

  2. Tom

    Hi John,

    Good review. Getting a WAV file to play was one of the first things i ever did on a microcontroller. Except i just hard wired a pair of ear plugs to the outputs on the microconroller and read straight off an SD card. Used the propeller micro to get the 44kHz in 16bit stereo. Worked well except it sounded very “raw” and scratchy. But when i connected to my home amp it was perfect.

    So I’m wondering that WAV shield must smooth the audio slightly.

    You should also try the VS1002 MP3 chip. That worked very well.

    1. John Boxall

      Hi Tom
      Thanks for your comments. The wavshield is somewhat more basic, I chose it for a talking clock project I’m slowly making… it just has to read out the numbers and “Hey, wake up!” etc. You’re right about the VS1002, I have been thinking about getting one of these The problem is too many things to do, not enough time 🙂

  3. Pingback: Waveshield kit review… « adafruit industries blog

  4. Forrest

    I like Yyour review! I was wondering could the arduino be multitasked? I mean, could you use an expansion shield to control servos while being a jukebox? or is that wishful thinking?

    1. John Boxall

      Perhaps, it depends on what you need to accomplish. For example, if your sketch tells the waveshield to play a tune, the waveshield will do so and the arduino sketch can carry on and do other things (such as run servos). Some careful programming should see your idea be a success. Best bet is to try a waveshield for yourself and experiment with it.

  5. Nicola

    I’ve run the waveshieldtest.ino sketch (the sketch extension has changed from pde to ino due to the new update) and I get the following error message:

    Wave test!
    Free RAM: 656
    Card init. failed!

    SD I/O error: 1, 0

    This suggests that it’s stopping when it get to this part of the code:

    // if (!card.init(false)) { //play with 4 MHz spi if 8MHz isn’t working for you
    if (!card.init()) { //play with 8 MHz spi (default faster!)
    putstring_nl(“Card init. failed!”); // Something went wrong, lets print out why
    while(1); // then ‘halt’ – do nothing!

    I do not understand why as I have formated the SD card to be FAT 16 and used the given audio file.

    Can anybody help or shed any light on this? and what does card.init mean?

    1. John Boxall

      The sketch may be incompatible with v1.0… there were many changes made from v23>v1.0. Try it again in v23. If that fails, ask for help in the support forums.

  6. Justin Things

    I bought this shield but was not happy to find that even the most basic sketch used around 1400 bytes of the arduinos 2k of SRAM.

    Cant get much else done using this shield. A cheaper and better option would be using the ‘Rugged’ brand Audio shield, or the BeatVox shield by the same company.

    Of course now you could also easily use the VS1053 breakout kit available at . It even costs the same as the now very ancient wave shield.


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