DIY Turntable

You always wanted to be a Disc-Jockey. You know nothing about beats, delays or mixing but, damn, scratching is like the coolest thing ever invented!

If this is also your case, follow this instructable to build a low-fi DJ set: the DIY Turntable as featured on Gizmodo and Engadget, and take the chance to recycle your old cassette player into a new cool instrument.

Step 1 Materials

Minimum:
- Cassette player (better if it's an old one)
- Wire and wire strippers
- Prototyping breadboard
- Soldering iron + solder
- Screwdriver
- 5 to 9V battery with battery holder
- Some kind of variable resistor or potentiometer

Advanced:
- Arduino with its USB cable
- IRF540 Mosfet (transistor)
- 5 LEDs
- 5 220ohm resistors (brown-red-red)
- one 1kohm resistor (red-black-brown)
- Computer cooling fan
- Box or some kind of enclosure

This project is divided in two parts. By doing only the basics you’ll be able to control the speed of the music  without even having to touch an Arduino or write a line of code. Almost zero budget and quite fun.

If you decide to follow to the advanced part, you’ll be able to have the pc fan act as a turntable (although it won’t be real scratching because the gears of the walkman won’t let you play backwards). You'll have total control over the speed of the music and will add whatever effects you like, like the LED indicator.

So, let’s get started!

Comments

[McMchriis]

Any Videooo!!!!

[samuelhtrowbridge]

I made all the connections, doubled checked the code to make sure I had the right pins, but the motor wont spin. I checked the motor and it works fine. I used the IRF540 Mosfet, could it be something with my fan? Or is there something else?

[araid]

Thanks for trying it. It's hard to tell what's wrong from here... I suggest you test things separately. Try to analogWrite a specific vaue on the motor pin, without using the fan. Then try to print the readings from the fan.

You can also try to plug it directly to the arduino pin and the ground, without the IRF540, and see if you can write enough power to run it.

Values will be different for every hardware, so you might have to play a little with them before getting the right effect.

[samuelhtrowbridge]

Thanks for the quick response. I tried reading the fan with analogRead, it only read 0 so i think the fan might be busted.

What's really strange is I tried plugging the motor directly to the arduino pin and the ground (i tried digtal and power to make sure) , but the motor doesnt budge. I tried digital and analog write with all different values but I know there should be no problem because I tested the motor with a D battery which is about 1.5V.

The arduino runs fine with everything else. What do you think?
Sorry to be a pest but this is really weird.

[araid]

I found the current to be as important than the voltage when trying to power motors, so, although you can power it with a 1.5V battery, yo might not be able to do it directly from the Arduino pin, since it provides different current.

From the Arduino website:
DC Current per I/O Pin 40 mA

On another note, although you can connect small motors to the Arduino, it's usually not recommended. That's why you would use a transistor inbetween. You can check out this tutorial if you want to know a bit more http://itp.nyu.edu/physcomp/Tutorials/HighCurrentLoads

Hope it helps

[ghurse]

If you are concerned that the Fan may generate more than 5V: insert a 5V Zener Diode from the Positive to ground, and a series limiting resistor. As input is a high impedance.. there should be no problem with that resistor being 47k but even a 4k7 will provide current limiting and allow the pulses from the fan motor. May I also recommend a .01uF ceramic or Poly cap across the motor as well as the zener.. some motors (typically the brush type) can generate some very potent spikes this will keep you from upsetting the Arduino input.

[araid]

Yes, the zener diode is a very good idea. As for the resistors, I initially placed them like a voltage divider (there are some equations if you google it) but I found the signal to be so weak that there was no way to exceed 5V.

But, again, it will depend on your fan, so it's always good to prevent!

[samuelhtrowbridge]

What's an easy way to see how much voltage the fan makes? Just attach to a multimeter and spin?

[araid]

Yes, spin as fast as you can an that's the maximum it will generate. Although it's quite jittery and can be hard seeing it with a multimeter. Maybe it's better to record it with the Arduino.

[soshimo]

You could also tie the arduino pin to the base of a tip120. Tie the ground of the fan to ground, and the positive terminal to the emitter of the tip120. Tie the collector of the tip120 to the fans positive supply (up to 12vdc for computer fans). You drive the fan using PWM to the base of the TIP120. You could also just write a digital one to the port tied to the transistor for 100% duty cycle.

[agis68]

wow.....is that a joke or what?....where are the LP's with the black shiny silked surface? where is the vermouth drink, the smooth lights....omg i belong to an old era.....ura! new turntables in shops doing what?????......omg

[DougtheMugDIY]

Twenty first century.
Get with the program brother....

[blinkyblinky]

Do I have to use a MOSFET?

[araid]

The IRF540 Mosfet is the one I'm used to, but you could probably use a similar transistor, like IRF510 or IRF520 or TIP120... just try with what you have.

[blinkyblinky]

Thanks.

[nigelh]

That makes three of us :D

[dokcal]

LOL! I'm so old, I think a turntable is a thing you play vinyl records on...

[crapier]

I think it is. I really wondered how he was going to get the capstan motor to spin a 12"

[WVvan]

That makes two of us.

[vincent7520]

more : at least three if you accept to count me in !!!.
;D

[DarkRubyMoon]

That is awesome! I've been trying to think of a use for an old cassette player! Now if I only still had cassette tapes lol

[araid]

Haha, I also had to go buy them at the thrift store

[jresqyr]

Groovy!