speakers and resistance

Hi there!

I'm trying to do this: Play a Melody using the tone() function and this is the hardware required:
Arduino board
8 ohm small speaker
100 ohm resistor
hook-up wire

But I only have 2 speakers made of 4 Ohm and a resistances of R. 470 ohm, R. 1 K and R. 10K.

I think I have managed to put the speakers connected in series to get 8 Ohm but now I don't know which resistance I could use to get the best results.

I would be very pleased if someone could clarify that.

Thanks in advance!

Use four 470s, connected in parallel, will be a little over 117 ohm. With the 8 ohms from the speakers, will be at 40mA, right at the edge of the pin output limits.

Use a blocking capacitor so the speaker only sees AC. Arduino pin to 150 ohm resistor, the to 47uF cap (+ve),
-ve side of cap to speaker, other side of speaker to ground.

You can use multiple pins each with 150 ohm resistor to the cap's +ve terminal to increase the power - just
drive the pins in unison to get more current to speaker.

Thank you very much, that's nice!

I'm just trying to put the resistances.

Cheers

It works! Tones of thanks :wink: