Hello
So I want to make a radio, but also I want to include mp3 Df player mini so I can listen to my favourite songs on the Sd card. But right now I am stuck on the Si470 part. I got it working with my headphones and pc powered speakers, but not with my normal 4 Ohm speaker. I don't know how to connect the 3.5 mm cable to speaker in the image. I searched online but cant find what I want. My Si470 doesn't have the "lout" and "rout" pins so I dont know if that will cause problems or they Just replace the headphone jack. I found on one of the forums that you shouldn't connect it to 4ohm speaker so I am a bit confused. If it is possible to connect(which Im sure it is) could you please explain how, or Just send a link Where it is explained? I am sure Its not the code because it works great with headphones and "normal" speakers.
I found on one of the forums that you shouldn't connect it to 4ohm speaker so I am a bit confused. If it is possible to connect(which Im sure it is) could you please explain how,
Yes it is possible to connect a 4 ohm speaker to an Arduino pin, but it will draw in excess of the maximum permitted current from the Arduino pin. The big problem is when it is silent. So it is best not to.
You can use a 33 ohm speaker with a 120 ohm series resistor, this will give you moderate volume if it is in an enclosure. Otherwise you have to use an audio amplifier between the Arduino pin and the speaker.
Anyway, I managed to connect the speaker to the 3.5 mm cable. I just switched the wires the first time. And yes, it is really quiet, so you were right I need an amplifier. Will 2n2222 do the job? At the moment I only have those laying around.
Only if you build it into an amplifier circuit, by itself it will not help.
There are some seriously crap designs out on the net. Look for one with a capacitor connecting the output to the speaker. Do not touch with a barge pole those that do not.
If it is not loud enough then try reducing that resistor connected to the collector more in the 100R range, keeping in mind the 500 mA limit on your transistor.
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