- CD drive motor
- Spacer to place the record on
- Power supply (3-12v)
- sewing needle
- 1k pot
- stiff wire or flexible metal for the needle
- receipt for the "speaker"
- A pumpkin
- And of course a record to play
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Step 1: CD Drive Motor and Spacer
this is pretty straight forward, you put the motor on a table and place the spacer on top. this motor i salvaged from an old DVD player that quit working, its not very powerful as far as torque goes so its not the best choice for this application but it will work. it can run on a little as 1.5 volts without a "load" on it but we will need alot more power to make this record spin. then i placed a plastic conduit washer on the top of the motor as my spacer. you can use anything for this, but this is what i had available.
Step 2: Powering the Record Player
To power the motor i used a 6 volt wall adapter. you can use anywhere from 5-12 volts for this once the 1k pot is connected. I connected the pot into the negative line between the motor and the wall adapter. i got this pot off a computer motherboard. it has 3 legs on it but you only need 2 of them, so if youre not familiar with pots then you might want to ohm it out with a meter to see which 2 are the adjustable ones since 1 is a constant. then once you have the pot wired up the wiring should be from the wall: positive to motor, negative to pot, then pot to negative on motor. The pot will need to be adjusted after the record player is ready so you can find out the correct speed for the player.
Step 3: The Needle and Speaker
the hardest part of making the thing was figuring out how to make sound come from it. you need the smallest needle you can get otherwise you will damage the record and it wont sound good because it will try to play multiple paths on the record at the same time. i used a sewing needle for this, it seems to be small enough to "read" the record and it doesnt damage it as far as i can tell. you will need to devise a way to let the needle follow the paths on the record as well, the needle cant be in a fixed position because it wont follow the path. i used some stiff copper wire to do this. i wrapped it around the needle and then wrapped another end around a pumpkin's stem.(you can substitute anything in place of the pumpkin) i left it loose enough so it can move from side to side to follow the record. it cant be too flexible though otherwise it will move back and forth on the record while its playing making the sound speed up and slow down. so alot of trial and error happend here for me.
next is the speaker. this could be any piece of scrap laying around your house really, anything from tin foil to plastic and styrofoam cups, to paper. different materials sound different, so play around and have fun with this part. i attached a receipt from walmart as my speaker. all you need to do to attach it is put the needle through it. thats really it! then to make it more stable and look better, just secure it the whatever you have holding the needle to the pumpkin is.
Step 4: Put It Together and Enjoy!
now for the fun part! put your motor on a flat surface and place the spacer on top of the motor. i didnt glue it or tape it, i just set it on there. place the record on the spacer. you can look through the hole of the speaker to to center the record so it wont be unbalanced and spin off the motor. the weight of the record hold it in place.
next place the pumpkin near the record and set up your needle and speaker. it needs to have enough pressure pushing the needle on the record to follow the paths but not too much where it will knock the record off the motor. thats why i used the copper wire, because its easy to adjust.
once the needle is set up, go ahead and power on the motor, making sure the pot is at its most resistance which means lowest voltage going to the motor. alot of power can kill this motor easily so be careful. with the power on, you can adjust the pot slowly until the record spins at a decent speed you think it should be. so now you can place the needle on the record and adjust the pot accordingly so the speed is right.
like i said before, there is alot of trial and error in this part. mainly the speed of the record and and pressure on the needle. too fast of a speed and the record sounds like chipmunks and such, too slow and it wont sound right either. the needle pressure and speaker material is also a factor. with some tinkering you can get the pressure right and speaker making noise, so just adjust the speed and youre good to go.
there is alot of fun in this project and the best part is that you can make it with almost any parts you have and make it your way. my way isnt the best out there by any means but it works for what i want it to . so enjoy and have fun!
Participated in the
The Mad Science Fair