I would like to add a stereo amplifier to a current project using a Mega 2560 (technically it doesn't even need to be stereo, but whatever). The thing is, the only thing I need the Arduino to control is the volume. I can provide external power to the amplifier (looks like I'd be basing it on an LM386) and I will be playing music from my MP3 player. I can't fit an MP3 shield into the project box, and that doesn't have the capabilities I want anyway. Also, I need it to be LOUD (50-100w speaker).
So what I'm thinking is using my 12v relay to power the amp (I have a relay in the project already with one open spot). I'm looking at this (http://www.instructables.com/id/Know-Your-IC-LM386/?ALLSTEPS) (and yes, I know to take instructables with a grain of salt). I like that style because it has an aux cable that I can use with my MP3 player. Am I on the right track?
So what I'm thinking is using my 12v relay to power the amp (I have a relay in the project already with one open spot).
Sorry no idea what that means. You can not power anything from a relay. Do you mean from the relay's power supply?
The LM386 will act as an audio amplifier. Forget the intsructables, just download the data sheet. You will see on page 6 that driving an 8 ohm speaker takes a few more components than the simple circuit used on page 5 and that link. The problem is keeping things stable. What has the Mega got to do with the project?
Grumpy_Mike:
Sorry no idea what that means. You can not power anything from a relay. Do you mean from the relay's power supply?
Yes, that's what I meant, sorry.
Grumpy_Mike:
The LM386 will act as an audio amplifier. Forget the intsructables, just download the data sheet. You will see on page 6 that driving an 8 ohm speaker takes a few more components than the simple circuit used on page 5 and that link. The problem is keeping things stable.
Fair enough. I'm willing to use more components, as long as they fit within my project box. I was going to use that instructable as a guideline and make something a little more "beefy," so to speak. Like I said, I need it to be loud. Perhaps I should just get a real amp, which is lame.
Grumpy_Mike:
What has the Mega got to do with the project?
I have a TFT with touch that I would use as the power button and for volume control. All the other components driven by the Mega are touch-controlled, so I'd rather just use that instead of physical switches. The volume up and down buttons would replace the pot in the above design.
The volume up and down buttons would replace the pot in the above design.
I think not. Not without something like a digital pot at least.
As to being beefy then that chip can only supply about 1W of power if you drive it with 16V so at 12V it will be some what lower. Is that beefy enough for you?
Grumpy_Mike:
I think not. Not without something like a digital pot at least.
Bummer, I was hoping to do that with a PWM pin.
Grumpy_Mike:
As to being beefy then that chip can only supply about 1W of power if you drive it with 16V so at 12V it will be some what lower. Is that beefy enough for you?
Sure isn't. Looks like I should just get a mini amp off Amazon. They're only like $10. Thanks for all your help!