Arduino to earbuds

Hey everyone! I need to hook up earbuds to my Arduino board and I have no idea how to go about doing that. Do I need resistors? Where do I hook it up? etc. I have the Arduino 101. Thanks!

I have the Arduino Galileo/101

What does that mean? As I understand it there is the Arduino Galileo and there is the Arduino 101, they are two different boards.

Do I need resistors?

Yes. Although it is best to use an amplifier as this puts a lot less load on the pins.

Where do I hook it up?

To the pin producing the audio output.

It's the Arduino 101, what amplifiers and resistors do I need?

The minimum resistance on an Arduino I/O pin is 125 Ohms.* If you want to be safe,** put a 125 ohm or greater resistor in series with the output pin. If you are connecting left & right channels to different Arduino pins, use a resistor on each output pin.

If it's too loud, use a higher value resistor. If it's not loud enough you need a headphone amplifier (which you can buy or build). A headphone amp will usually have a volume control so you can make it louder or quieter.

  • The Arduino pins are rated at 40mA absolute maximum. From [u]Ohm's Law[/u], 5V across 125 ohms is 40mA.

** The resistance/impedance of the headphones is added to the resistor value. So for example, if your headphones are 32 Ohms you could use a 100 Ohm resistor and the load would be 132 Ohms, which would be OK. But, a 125 Ohm series will protect the Arduino from any load, including a short (as long as the short is after the resistor).

The minimum resistance on an Arduino I/O pin is 125 Ohms.*

But I don't think this applies to the 101, that is a totally different processor. It uses a 'Intel Curie', I would be surprised if it is as robust as the Atmel chip.

Edit :- None of the data sheets I have managed to find says what the output source or sink current is.