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Hey, /diy/. I'm working with a Raspberry Pi project to turn an old FM radio modeled after a PC into a fully functioning computer. I have removed the speaker grill and sanded it, but now I'm looking to attach the original speaker to the Pi's audio output with adjustable volume. I'm using the Adafruit 2.5w amplifier (pictured with speaker) which works great, but now I need to figure out what resistance of variable resistor I need to adjust the volume properly.
The speaker is 8ohm 2.5w. Would I use a 5k ohm resistor for this? Or a 1k ohm? I'm new to electricity so I'm confused of what I would need to calculate. I cannot use the original potentiometer unfortunately because turning it about 1/4 inch of its range just kills the audio volume to 0. Any help would be appreciated.
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You need an audio / log taper pot. Put it in front of the amp, wiper goes to the input of the amp, audio output and ground across the pot.
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>>1165364
Okay noted. Would there be any you would recommend for such a low power situation?
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fucking 4chan just nuked my long post. not gonna write all that shit again, so here is the condensed version:
use any old audio pot, like the one salvaged from the radio or from an old set of computer speakers, or a new one like this: http://ca.mouser.com/ProductDetail/Bourns/51AAA-B28-D15L/?qs=sGAEpiMZZMtC25l1F4XBU7rZyhV5cpJRUp4dZxkFMSk%3d
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>>1165391
Would 5k ohm pots do the trick? I can get metal-body ones pretty cheap on ebay. Or should I stick with 10k ohm? Does it even really matter I guess is my whole question.
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anything from 500 to 50K should be fine. all you really care about the angle of the knob, which corresponds to the output signal ratio. the actual resistance value is not important, as long as it's reasonable.
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>>1165345
WTF am I looking at? PC shaped speaker tower? Why? When did they make those?
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>>1165415
Woops, I meant to get the audio version. Hope this works
>>>/wsg/1649705
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>>1165416
That is actually pretty fkn sweet man.
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http://hackaday.com/2014/07/15/raspberry-pi-turns-a-novelty-radio-into-a-real-computer/
and the gallery
http://imgur.com/a/5xiPJ
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>>1167730
No I understand, thats where I got the idea from + a teacher in the school district I work at has a novelty radio like that. His guide is utter shit now because he used a very first Pi model and as such, he hacked a shitload of stuff together that isnt necessary anymore. He doesn't even have a volume control
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