Fred 453 Posted June 6, 2013 Share Posted June 6, 2013 There's a few threads on MSP430 audio playback and they've prompted me to wonder what's the best way to actually play the audio (i.e. drive a speaker, piezo) for a simple battery-powered kid's toy? A lot of stuff I can find on audio generation stops at the output to an amplifier. I've seen a few examples of directly driving a speaker (via a low pass filter) from a microcontroller pin but that doesn't seem ideal. The background to this: My 1.5 year old son likes sitting on and starting my motorbike and I've just got him his first balance bike. I'm sure he'd love a starter button and some engine noises on his bike. I'm obviously not after great audio quality, just reasonable (ideally adjustable) volume and battery life for a toy. Quote Link to post Share on other sites
simpleavr 399 Posted June 6, 2013 Share Posted June 6, 2013 I am gonna say for toy sound (which is lo-fi but need to be "loud"), you will need some kind of amp. A TDA2822M would do nicely, LM4871 would give better quality (low THD, I used it for bluetooth speaker). There are many more better chips. These two I had used successfully at 3V and very low cost at ebay. But for your purpose, you may consider a "recordable greeting card" module, cost you $5.00 at ebay. No worry on eeprom, amp, pwm, etc. Just "clone" the sound from your bike and stick the module to your son's vehicle. Fred and bluehash 2 Quote Link to post Share on other sites
rockets4kids 204 Posted June 6, 2013 Share Posted June 6, 2013 The "jellybean" amp/speaker driver is the LM386. This chip is perfect paired to your generic 3" 8 ohm speaker. You should be able to find plenty of information on the web about how to drive it. If you need a little more volume, there are a huge number of options. Unfortunately, I don't have any specific recommendations here. I have been scrapping old CRT TVs for parts, and this is a great source for audio amplifiers and speakers. Almost invariably the amplifier chip is a TDAxxxx part and a datasheet can easily be found with a web search. Fred and bluehash 2 Quote Link to post Share on other sites
Fred 453 Posted June 6, 2013 Author Share Posted June 6, 2013 Thanks. I'll take a look at those amps. Whilst I'd like to do it myself (and perhaps monitor wheel speed to generate an engine sound at appropriate RPM) the greetings card module might be a nice quick win. I just ordered one. Quote Link to post Share on other sites
spirilis 1,265 Posted June 6, 2013 Share Posted June 6, 2013 One of my tinker projects on my plate is to try using my F5172 launchpad with a lowpass filter and see how well it can produce PCM audio ... I think it should be fast enough to do CD quality albeit at 10 bit only. This chip also has 5V / 20mA drive capability on its DVIO ports, that might be able to drive a speaker better. Definitely going to look at some of the chips mentioned here. Quote Link to post Share on other sites
Fred 453 Posted June 6, 2013 Author Share Posted June 6, 2013 It was you wav music player thread that prompted me to ask - I just didn't want to drag that thread off topic. I have so many "tinker projects" going and half finished that using the recordable greetings card is probably the best idea. I'm distracted and spread too thin already. Quote Link to post Share on other sites
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