Minature loudspeaker with Arduino

Hi all, I need to connect a speaker to my Arduino that needs to give more sound than a buzzer does. However, I don't know what one I can get away with from this website:

Can anybody shed some light on the situation? Thanks in advance.

Update: I just got a 8ohm 0.5W speaker from a mate that works. I assume it is safe to use?

No not straight off. :frowning:
If you connect an 8 ohm speaker to 5V it will want to draw 625mA. The output can only supply 65mA, after that although it will limit the current you might find the output commands don't work due to the reading back problem.

You should connect this up through a transistor and couple it up through a capacitor.

Ah, thanks for your reply Grumpy_Mike. I don't know if it makes any difference but I'm not actually connecting it to the 5V pin. I have the red wire going into pin 8 and the black wire into a ground pin?

Thanks again.

it doesnt really matter where you connect it. if theres a connection to ground and a pin that is high (+5 volts) it will try to draw 625ma. an alternative to the transistor capacitor method is using a lm386. its overkill, but you can hook up other sound sources to it to play around.

Thanks weirdo557.

Do you know what value transistor and capacitor I will need? Also, do you know of any diagrams on how to hook it all up?

Thanks in advance.

try a radioshack TIP120 NPN-D transistor. overkill, but itl keep you from blowing it up.
Transistor Circuits <- this site shows you how to use it like a switch, just substitute the +9v for your 5 volt power rail and connect that to the emitter. connect the base of the transistor to the arduino pin with a ~200 ohm resistor, and for the load, connect your speaker in series with a capacitor ~220uF between the collector pin and the ground