Instructables
Here's a great demonstration of how a motor can be used as a speaker for less than 5 dollars. It took 5 minutes to put this whole thing together, without soldering a thing!
 
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Step 2: The Schematic

Here's a schematic so that it's easier to follow along. If you don't know what a schematic is it's basically like a little map of electronics that tells how things are connected. The big rectangle thing is the chip, and the rest is pretty self explanitory.




numbering of pins on the 2nd picture
R.A.T.M2 years ago
ll you neesis stero no mplfier
gavras3 years ago
can i use instead the motor a relay? to make lights go with music
Sandisk1duo5 years ago
so is the chip a good amplifier? b/c i want to build a bunch of cheap speakers to sell at school
yea but u wanna put a large cap(1000uf or greater) on the output.. i made one and hooked it up to a 4x1" oval speaker w/o the cap and it was all fuzz.. then i put in the cap and it sounded great pretty good.. ive experimented with different speaker sizes, up to around 5 or 6" round, and all have worked good.
i know your post is old but a mega thanks for posting this. my friend has been hassling me ever since hesaw my speakers i had and now he wants some and i dont want to make the extra trip to buy some more. now that you have told me this i can make my own so he can leave me alone.
um lets say pin 5 ran away dont as is there any alternatives plz help thx
Unit0424 years ago
I did this a while back (using a pair of transistors instead of an LM386), using a small fan motor. The idea was, the fan motor would play music with its internal coils while spinning, keeping me cool. Turned out the motor would turn/respond to only the lowest of frequencies, even then, it hardly worked. Sigh...
comodore6 years ago
HI! Me again. :) Earlier I asked you about the headphones. So I just make this schematic and instead of the motor I put an LED? Cool! Shouldn't be too hard. Do I really need the 6V battery??? When I make this I just hook it up to the headphone speaker an it should work, right?
guyfrom7up (author)  comodore6 years ago
you need some sort of voltage supply, such as 5 volts, or 6 volts. I just chose 6 volts cause I had that lantern battery lying around. It won't work without the extra power good luck :)
I would use the power supplied from a USB cable(I'm all out of batteries, and don't feel like killing myself with 120V), since it generates about 5.25 to 5.75 V of voltage and about 100 to 500-600mA of current. And like you said, I just had the severed USB cable lying around.
Braeburn5 years ago
all you have to do is put headphone wires onto a motor and plug it into an ipod
If you connect it directly to the motor the music player, the large inductance of the motor will damage it. Like connecting a transistor directly to a relay, the voltage spike will damage the transistor. Normally you would add a diode, but sound is AC so it wont work.
i tried similar stuff with way bigger inductoprs (about 1.5 HY) and did not damage the player you may add 2 very fast diodes in parallel to the motor in both directions. i think itll be relatively good protection. unless the voltage is above 0.7 V i dont think theyll affect the sound much. for higher allowed voltage connect some diodes in series
It's just like connecting a relay to a transistor. You have to add a protection diode to block reverse-EMF signals from damaging the transistors. Unless the player has it own protection, it will damage it.
i guess you are right here. i just say that i did something more severe and did not blow up my player since diodes open only at 0.7 V maybe you can use them in both directions for protection. and maybe connect in series to get freedom up to 1.4 or 2.1 V etc
MJTH5 years ago
The guy below me Kenny94 is absolutely right, all you have to do is chuck the headphone wires to the motor ones. The chip doesn't really do anything. Ive done this before and the only reason why the motor sounds so loud is because it is on top of the metal which echoes it through that and through the table. If he took it off you would hardly be able to hear it.
Padlock MJTH5 years ago
If you connect it directly to the motor the music player, the large inductance of the motor will damage it. Like connecting a transistor directly to a relay, the voltage spike will damage the transistor. Normally you would add a diode, but sound is AC so it wont work.
srhadaham5 years ago
from my experiences adding extra power to the audio in of any device is a bad idea. fried my last mp3 this way
Sandisk1duo5 years ago
Can you hoock up a speaker to it?
You can hook the speaker to to the player without the chip.
ya, but doesn't the chip amp the volume?
Thats true, but it's a low voltage amp anyway. Not gonna do much with a speaker.
but still, it makes it louder then it was originally
Goldtechnic5 years ago
Hi guyfrom7up, what kind of motor is classified as "slow"? Can i use those tamiya plasma dash type of motors? thanks.
o_k_boy6 years ago
Hi, thanks very much for this. just a quick question - in step 9 where you connect the battery to the chip, should it really be connected to pin 5? nobody else seems to have any trouble but on the datasheet i've got for the lm386 it looks like it should be pin 6.
guyfrom7up (author)  o_k_boy6 years ago
.... huh, that's weird. Well I hooked it up to pin 5 and it worked fine, lol
Trekky 17006 years ago
Does the motor spin?
guyfrom7up (author)  Trekky 17006 years ago
yep
of course! I've had much trouble with stripping fine wires in the past. Good tip.
I have the same earbuds.... they work really bad.. :( :P
It would be interesting to hook up your system to a small electric car :)
rocking
pablo6 years ago
That's fwicked! Do you reckon this would work with a drill?
Kiteman6 years ago
Sorry, but I can't hear anything on the video My speakers are a bit iffy - is all the sound on one channel?
guyfrom7up (author)  Kiteman6 years ago
The project is mono, but the video is stereo. It's kind of a quiet video, but whenever I editted it I made it twice as loud. If I'm not listening it through headphones I have to put my speakers at about 1/4 power. And I have the cheap kind of speakers that come with the computer. The loudest thing in the video is a phone ringing in the begining, so you shhould at least be able to here that.
guyfrom7up (author)  guyfrom7up6 years ago
actually I see what you mean. With background noise and if you're not really listening for it you can miss it. Here's 2 options 1) put on headphones 2) crank up your speakers, don't worry nothings too lound, like I said before, the phone ringing in the beginning is the loudest part. I might upload a different video (same video, just making it louder.
guyfrom7up (author)  guyfrom7up6 years ago
New video, made the audio much much louder, you should have no problem now
Wow, that is rather cool.

(My "to do" list is sooooo long, and I'm back at school on Monday!)
Pyrowuzzup6 years ago
lol nice. now you just need to make it stereo. you can also use a lighter to melt uninsulate earbud wires
guyfrom7up (author)  Pyrowuzzup6 years ago
I usually use a lighter, but there's 2 problems in this situation: 1) Would be safe for younger kids (for a SCIENCE FAIR type of thing) 2) These earbuds were so cheap (worse than dollar store quality) that as soon as you light it the whole wire falls apart in a black and white cidery ash. Thanks for the suggestion though!
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