plug audio speaker to arduino
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plug audio speaker to arduino

by alex_hurz on Fri Nov 23, 2012 12:01 pm

hello there,

am currently working on a small public project due next month. basically a shooting game where the player throw some kind of a ball at a board with a central button (how more boring could it sound...) then once hit, a servo, a RGB LED and a piezo go crazy like there's no tomorrow.
so far so good. everything's working...but now i would like to increase the volume of the playing tune.
the piezo i'm using is the one from the kit... it's cute and nice but i really need louder...so basically swapping it with a bigger speaker...

so now i have this speaker 5W 8ohm in my hand (like litterally i'm holding it right now in my hand...and typing with the other...and it's just taking too much time...so i'll just leave it on the table). am using an arduino uno and i just don't want to fry my new baby toy...

i posted "on arduino cc forum" and the best advice i could get was "Ohm's law isn't that difficult"... i mean seriously? if cross-multiplication was ever an issue i wouldn't have dared to post anything...nor show my face on the street.
ok so far (nod if correct) here's my understanding of it: some current (the rest that isn't being used from the led, servo, button) will go to the speaker?...
but then what? what am i suppose to equate in my calculation? how much current is needed to produce noise with this speaker...

i'm sure you can tell i'm pretty lost. please help me. i will dance for you if you do. thanks

ps: i've already checked the arduino/tutorial/tone...it shows a speaker but doesn't indicate the watts...so i just got scared...i know lame.
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Joined: Fri Nov 23, 2012 11:29 am

Re: plug audio speaker to arduino

by adafruit_support_bill on Fri Nov 23, 2012 1:42 pm

You won't be able to drive that speaker direct from an Arduino pin effectively. In fact, you risk burning out the pin due to excess current draw. What you need is an amplifier such as this one: http://www.adafruit.com/products/987. You will want to add a volume-control pot between the output pin and the amp and use the lowest gain setting. Otherwise, the 5v signal out of the pin will overdrive the amp.

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