Go Down

Topic: * MP3 Shield * - Rogue Robotics rMP3 (Read 47427 times) previous topic - next topic

Lee Sylvester

L and R provide accurate activity for that sort of thing ;-) Why not branch from there for both output and route to analog input in the Arduino? I don't know what the upper or lower values for those pads are (maybe in the docs?), but it's surely a valid option. Just make sure it doesn't exceed the pins impedance.

mowcius

#16
Apr 08, 2010, 09:03 pm Last Edit: Apr 08, 2010, 09:04 pm by mowcius Reason: 1
You mean speaker L & R?
That requires all the annoying circuitry in between to get that to work...
I suppose i am more asking about a frequency visualiser which is more complicated...

Mowcius

Lee Sylvester

Not necessarily. The analog input in the Arduino can take any value between 0v - 1v (I believe), so, as long as you limit the voltage (using the correct resistance), then you have a simple variable source right there. The biggest issue is making sure your querying of that source doesn't use the potential that would otherwise drive your speaker output (though you could increase that with an amp).

mowcius

Quote
0v - 1v (I believe)

You mean 0 - 5v (well it's more like 0 - 5.5 but that's pushing it a bit.)

Lee Sylvester

Yeah, 5v... That's what I meant ;-)  Well, you're okay, then, seeing as 5v is the maximum voltage anywhere past the regulator! Hook even one of those pads into the Arduino and use it as an input. Actually, you could also average the highs and lows so as to get better results, as those highs and lows will be quite similar in value.

bhagman

#20
Apr 09, 2010, 12:45 am Last Edit: Apr 09, 2010, 12:47 am by bhagman Reason: 1
You have to be careful when using audio signals.  The output from the rMP3 on the L and R pins are actually AC signals (because of the filter capacitors on the outputs).  This means that the voltage with respect to ground on those pins can be negative, if you connect them to the analog inputs on the Arduino.  This can damage the ADC on the Atmel chip.

You could introduce a DC offset, but that will require extra components which I think mowcius is trying to avoid.  :)

I'd stay away from connecting the audio output to one of the analog inputs, unless you know what you're doing.

mowcius - your wish is my command.  Here is the updated documentation on the input interface:

http://www.roguerobotics.com/wikidocs/rmp3/documentation/input_interface

b

Lee Sylvester

Hadn't thought about it being AC (which should be as obvious as the nose on my face), but it's nothing that a handful of diodes couldn't fix. In fact, one could always route the negative edge to a separate pin as a positive feed. :P

mowcius

#22
Apr 09, 2010, 10:58 am Last Edit: Apr 09, 2010, 11:03 am by mowcius Reason: 1
Quote
mowcius - your wish is my command.  Here is the updated documentation on the input interface:

http://www.roguerobotics.com/wikidocs/rmp3/documentation/input_interface

Oooh, I do feel powerful :p

I presume it is still on the list but what do all the other pads do? From the looks of it, some could be for an FTDI header?

Quote
You could introduce a DC offset, but that will require extra components which I think mowcius is trying to avoid.

Aye, I will look into it with as few components as I can get away with though :p

Mowcius

bhagman

All the connections are described in detail here:

http://www.roguerobotics.com/wikidocs/rmp3/documentation/connectors

It's got:

Arduino compatible shield connectors
FTDI/SFE-DEV-09115 cable connector
Digital trigger connector (trigger with digital inputs)
... among others

b

Sannin

I was wondering if you guys plan on coming up with a cheaper version of your MP3 shield. Like Sparkfuns?

Lee Sylvester

Sparkfun's MP3 breakout is far less functional. I really had to search high and low for a "high quality" and flexible MP3 board for my JukeBox project I'm building. There just aren't that many out there. It was pure luck that this one was already arduino compatible, because I was quite prepared to fashion one into an arduino ready product.

Sannin

#26
Apr 18, 2010, 11:36 pm Last Edit: Apr 18, 2010, 11:39 pm by Sannin Reason: 1
Sometimes less is more. ;)

for example
http://www.micro4you.com/store/Arduino-MP3-Shield/prod_122.html


bhagman

I never had a problem with that shield - until I tried to use it.  You pay less for more work (and more headaches, and more technical jargon, and so on).  If that turns your crank, go for it.  The adage always holds true: "You get what you pay for".

I'll put forward a challenge to you though.  If you can explain the differences between that board and the Rogue Robotics rMP3 shield, I'll send you a free rMP3 shield.  [Offer only valid for Sannin ;) ]

b

P.S. I'll steer clear of the fact that they also use Arduino in their product name when it clearly isn't endorsed by the Arduino Team.


miliatov

sorry if the question is silly...

I am building a small installation where PIR sensor will detect presence and start playback of two audio files simultaneously at two different locations.

If I stack two rMP3 players on top of one arduino board, will both of the players start playback simultaneously when 'play' command is sent through pin 6, or do I need to rewire pins on the second shields and have a second 'play' command sent through the rewired pin.

thanks,
M.

Go Up