Eleven/Arduino and Audio

The "Eleven" is our Uno-equivalent Arduino-compatible board, but with a number of improvements including prototyping area, a mini-USB connector, LEDs mounted near the edge, and the D13 LED isolated using a FET. [Product page]
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Sullo321
Posts: 2
Joined: Tue Feb 14, 2017 12:36 am

Eleven/Arduino and Audio

Post by Sullo321 » Tue Feb 14, 2017 12:54 am

Hi,

I have posted seperately about loving the Eleven and making good progress on LED and servo functions for a dollhouse.

The next functionality I would like to add is sound beyond melodies.

I have an SD module from another supplier as Freetronics did not have one but unclear as to how to use with an 8ohm speaker. There are conflicting posts online in relation to being able to plug the 8ohm speaker directly to arduino pins. Some websites appear to show it for the melody option and some use it for "bigger files".

It seems more likely to me that the speaker should not be plugged directly to pins but first have a resistor placed before it.

In any case, I have come across this page on the arduino website but it appears to be for a due rather than an uno.
https://www.arduino.cc/en/Tutorial/SimpleAudioPlayer

My question is, will this set-up work just as well for the Eleven or does it need to be modified.

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stryker
Posts: 268
Joined: Sat Jan 14, 2012 2:44 pm

Re: Eleven/Arduino and Audio

Post by stryker » Wed May 17, 2017 4:52 am

That will work fine with an Eleven. I have often added a LM386 amplifier to Arduino projects. I have a couple of Elevens that form the basis of halloween decorations that play samples off SD using the Adafruit WAV Sheild. One of those I use a small practice guitar amp on the output which is something I built based on LM386. It's a very simple and useful amplifier chip. I honestly don't recall what the impedence on that speaker is, however it was salvaged out of an old TV so it won't be too exotic.

The LM386 datasheet says it's happy for speaker impedence to range between 4 and 32 Ohms so 8 should be just fine.

FWIW the best result I've had with the LM386 was in a car-mounted project. They do appear to enjoy 12V.

Geoff

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