Hello,
I am completely new to using an Arduino in combination with frequencies en speakers.
I want to use the Arduino (in combination with a Raspberry Pi or my MacBook) to send frequencies to a speaker. I will use a 8Ω, 150W speaker or a 8Ω 200W speaker. What kind of amplifier do I need and is there a change that I'll overload the Arduino in some way?
I'm looking for a code to send the frequencies to the Arduino as well, perhaps with the use of a potentiometer to changes the frequency.
All suggestions are welcome!
If you have Raspberry Pi or MacBook either of those can easily send audio to speakers through an amplifier. What would an Arduino add to what they can already do?
Steve
What are the Pi and Macbook doing?
You can use the tone() command to make the frequencies.
How loud do you want the output?
I'd start with some simple self-powered computer speakers to start.
I have an old pair of Gateway 2000 speakers like this that I use
Run the Arduino thru a 1uF or 10uF cap to remove any DC from the signal (makes the output look like +/- 2.5V signal), and a resistor divider to bring the level down and prevent distortion (say by half or less, to around +/- to 1.0 to 1.25V).
Can use a potentiometer for that as well.
I want to use the Arduino (in combination with a Raspberry Pi or my MacBook) to send frequencies to a speaker.
In your head you know what that phrase means but to us it can mean many things. So what exactly are you trying to do? What you put is not what you want to do, but how you think you should do it.
I will use a 8Ω, 150W speaker or a 8Ω 200W speaker. What kind of amplifier do I need and is there a change that I'll overload the Arduino in some way?
If you use an amplifier you won't overload the Arduino. (Without an amplifier an 8-Ohm speaker will draw excess current and you can damage the Arduino... The minimum resistance on an Arduino output is 125 Ohms for the "absolute maximum" current of 40mA.)
The speaker's wattage rating is it's maximum peak "program material" rating. It's OK to use a lower-power amplifier... You can use a 1W amplifier with a 200W speaker if its loud enough for you. And, 1W may be louder than you think... A 1W constant tone should be loud enough to annoy everybody in the room! 
Music and voce ("program material) has a peak-to-average ratio of 10:1 and with a 200W speaker you can use a 200W amplifier that's hitting 200W on the peaks and averaging about 20W. If you run 200W constant-tones into a 200W speaker, you'll fry it! If you have a 2-way or 3-way 200W speaker, the tweeter has a much lower power rating than the woofer and you can blow the tweeter with high-frequency tones at a couple of watts.
I'm looking for a code to send the frequencies to the Arduino as well, perhaps with the use of a potentiometer to changes the frequency.
Ignoring Wi-Fi and all that for the moment -