For my thesis I integrated sound playback circuits into portable, battery powered devices. This is a common thing to do in the world of interactive media, but the choices you have in what to use are varied, and the trade-offs are vast. I have spent the last several months accumulating and testing a variety of chips and choices, and I thought I would make that process a little bit easier for the next person by consolidating what I’ve learned in the process. I think my ultimate assesement of the situation is to use the simplest solution possible. If the $12 radio shack circuit works for your application, USE IT.
Intro
When you decide you need audio recording and/or playback in your project, there are several questions to ask yourself:
- Do I need to record AND playback? Or just one or the other?
- What level of sound quality do I need?
- Are the sounds fixed or changing based on some sort of input?
- Do I need to play one sound or many?
- Are the sounds triggered or occur without user input?
- Must I use batteries or can I be plugged in?
- Can I get away with just using a computer?! (this is a BIG one…)
Answering these questions ahead of time will help you focus your search and make the right choice. Here is a list of the sound record/playback solutions I review here:
Cowlacious ISD1700 Kit
ISD15100 Chip and Evaluation Board
Waveshield
Coby Hacked MP3 Player
MOD-MP3 Sparkfun MP3 Player
VMusic2 MP3 Player
SPECS
Price: $27-33 for playback only | $43-49 record/playback
File Format: Wave / Analog Input
Quality: Low / 12khz (best for speech, passable for music)
OVERVIEW
The Chipcorder series of IC’s from Nuvoton is a great place to start with chip research and the ISD1700 Series is particularly flexible and easy to use. Several companies make kits with these chips, which is a real handy way to get making immediately, without pulling your hair out just getting sound playing. Simply buy the kit, record sound in, and trigger to get sound out. Easy.
Note: There are several companies that make kits with the ISD1700 chips, so google around. Cowlacious just makes a particularly easy and robust one, and they come pre-assembled.
PROS:
- Works out of the box. Just power it up and start recording in.
- Easy 5v trigger input for triggering sound playback.
- Can purchase one Record/Playback kit and then as many Playback-only kits as needed
- Speaker and Analog outputs for powered or nonpowered speaker setups.
CONS:
- Sound quality limited to 12khz sampling rate (good for voice, poor for music).
- 8 minutes maximum of playback time (at their lowest quality, 4khz sampling rate).
- Analog input only for getting sounds into device.
COMMENTS:
Having spent a lot of time making custom circuit boards for the chipcorder series of chips in the past, I can say that this is a great kit that instantly lets you record sounds and integrate into a triggered playback system. The documentation is clear and the kit comes pre-assembled and is easy to use. If you need basic, low quality sound recording and triggered playback, this is a great way to go.
LINKS
Cowlacious ISD1700 Kits Products Page
ISD1700 Series Home Page
ISD1700 Series Data Sheet
ISD1700 Digikey Page
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Sparkfun MOD-MP3 Breakout Board for VS1002 MP3/SD Module
OVERVIEW
This is a pretty nice mp3 breakout board that Sparkfun sells. It is based on the VS1002 surface mount chip, and having it all broken out on a board you can use without having to solder surface mount chips is a real plus. On the other hand, getting it to do anything but playback upon receiving power takes some real hacking and might be more trouble than its worth.
PROS
- MP3 Quality Audio
- SD Card for Sound Storage – easy loading of songs / tons of space
- Breakout pins for control via microcontroller
- Hacks for using without microcontroller
CONS
- Very little documentation / No real Sparkfun support
- Difficult to hack your own sensors for it
- Sparse documentation for controlling with microcontroller
COMMENTS
I came very close to using this for my project, but ultimately it was just a bit too cludgy. If you need to use a microcontroller to get it to work well anyway, you might as well use a Waveshield instead.
LINKS
Sparkfun Product Page
Olimex Product Page w/ schematics, sample code, etc
VS1002 Page (MP3 chip at the core of this circuitboard)
Info on using this board without programming or microcontroller (very helpful!)
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OVERVIEW
I bought one of these but didn’t even get around to testing it out. If anyone wants to review it, please drop me a line at mike [at] thetanknyc [dot] org
PROS
CONS
COMMENTS
LINKS
Product Page
Data Sheet
Schematic
Buy Online from Mouser
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ISD15100 Series USB Evaluation Kit
OVERVIEW
So I will start by saying that the size of this evaluation board is insane. It’s huge. But don’t let that throw you. The chip itself is actually a tiny surface mount and is quite versatile. The ISD15100 series of chips is Nuvoton’s highest quality line. The audio quality is fantastic and if you are looking to produce devices on any kind of scale, I’d say they are worth looking into. The evaluation board comes with software that lets you digitally load files to the chip and set pretty much everything under the sun.
PROS
- High quality audio (uncompressed WAV, digitally transferred via USB)
- Small footprint (of the chip itself, not the evaluation board…)
- Low price
- Easy to build a small, targeted circuit around the chip to meet the particular needs of your project
- Well documented
CONS
- Surface mount chip makes for difficult soldering
- Evaluation board is over $200!
- Software is Windows only
COMMENTS
I would say this chip is best for pretty serious projects and not just for the enthusiast or dabbler, or even the midterm project! But if you have a sound record/playback device that you want to ramp up into production, it might be worth checking out.