Requirements are.
Stereo.
Input: any file like WAV, MP3, PCM, custom data format on SD card or EEPROM.
Input data will be prepared before end.
Output: Right channel, line level. Left channel,
medium/low power speaker.
Immediate turn on / off. In other word no implementation asking to wait for booting / shut down.
Wishes.
Low cost, using ready made proven modules.
Power supply included.
There are many solutions, from using parts reinventing everything up to using a microcomputer as long as, OS booting and shut down is not needed ( stand alone, using BIOS would be fine ).
I would like as little as possible hardware development. Programming is fine.
Ultra low cost is the challenge.
Stereo.
Input: any file like WAV, MP3, PCM, custom data format on SD card or EEPROM.
Input data will be prepared before end.
Output: Right channel, line level. Left channel,
medium/low power speaker.
Immediate turn on / off. In other word no implementation asking to wait for booting / shut down.
Wishes.
Low cost, using ready made proven modules.
Power supply included.
There are many solutions, from using parts reinventing everything up to using a microcomputer as long as, OS booting and shut down is not needed ( stand alone, using BIOS would be fine ).
I would like as little as possible hardware development. Programming is fine.
Ultra low cost is the challenge.
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With a google search "MP3 player module" I found DFPlayer Mini that fills the bill.
I found other modules that presumably are variants around the same IC.
I could not identify the used IC to know exactly what they are selling.
I found other modules that presumably are variants around the same IC.
I could not identify the used IC to know exactly what they are selling.
Having tried out a few of the very cheap MP3 players on Taobao, I've found this one to be the best overall. Most resilient in practice - you can pull the card out while it plays and it'll just mute for example - although a very long way from being the cheapest. In the general scheme of things though, $12.5 is incredibly cheap for what's on offer.
??/????WAV/APE/FLAC??AK4495???I2S?SPDIF????-???
??/????WAV/APE/FLAC??AK4495???I2S?SPDIF????-???
This BT module will also play mp3, wav, wma, and flac files if microSD card or USB memory stick/HD is inserted. The sound quality is very good. Needs 5v power. Only $6.
SANWU bluetooth Audio Receiver Digital Amplifier Board With USB Port TF Card Slo | eBay
SANWU bluetooth Audio Receiver Digital Amplifier Board With USB Port TF Card Slo | eBay
What is the IC on the board .. seems to be only one IC on the board taking care of all the functionality..
It must be a custom ASIC from Sanwu. Stamped JL AC1648DAB244-2 (Google does not turn up a match). It is indeed the only IC on the board, paired with an external Xtal oscillator.
No, the USB port is just for reading thumb drives (or USB card readers). If you want to connect a DAC you'll need the board in post #3 as that has I2S output (no USB out).
From memory I think it was under 100mA (from a 5V supply) on my most recent purchases - it varies depending on whether you use BT or play from SD. I do recall when I first got my hands on one (over two years ago) I noticed that it ran fairly hot. But when I bought some again earlier this year the thing surprised me in that it ran pretty cool. Perhaps the firmware got an upgrade in the meantime.
What is the pitch accuracy from these very cheap MP3 player ?
I see no clock or external clock input. I fear, the internal clock oscillator is not so good.
I need better than 1%frequency accuracy.
On the DFPlayer Mini manufacturer site, I see the chip comes in two flavors where the only difference is, one has "high quality".
What different quality could this be ?
There's a crystal above the microcontroller on that picture, a 5x7mm or 3x5mm low profile package. There's always a quartz crystal reference for audio DACs.
As for the absolute accuracy that's another matter, but even cheap crystals these days are +/-50ppm.
As for the absolute accuracy that's another matter, but even cheap crystals these days are +/-50ppm.
I see, my question can be confusing.
I am ont talking of the microcontroller Xtal clock.
I am talking of the chip in the DFPlayer Mini module. This has no visible Xtal.
Here is a link to the manufacturer of the DFPlayer Mini.
YX5200-24SS MP3 Chip
DFPlayer Mini MP3 Player Module for Arduinio Manufacturer
I am ont talking of the microcontroller Xtal clock.
I am talking of the chip in the DFPlayer Mini module. This has no visible Xtal.
Here is a link to the manufacturer of the DFPlayer Mini.
YX5200-24SS MP3 Chip
DFPlayer Mini MP3 Player Module for Arduinio Manufacturer
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My guess is the 'high quality' one is new, the other is of dubious provenance. Could be a pull for example.
@Mark Tillotson - I took my verniers to the XTAL package on the CPU module, its 3.1mm * 2.4mm.
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Pitch accuracy might be an issue with the cheap MP3 player I have in mind.
DFPlayer Mini.
YX5200-24SS MP3 Chip
DFPlayer Mini MP3 Player Module for Arduinio Manufacturer
As said in the OP, I need 1% accuracy.
This chip decodes mp3 using an internal clock. Who knows about this clock, presumably a silicon based clock, may be ceramic, not as good as a Xtal clock.
All I could find:
Maxim chips silicon based clock with 2% accuracy.
Ceramic resonator said to be 0.5%.
DFPlayer Mini.
YX5200-24SS MP3 Chip
DFPlayer Mini MP3 Player Module for Arduinio Manufacturer
As said in the OP, I need 1% accuracy.
This chip decodes mp3 using an internal clock. Who knows about this clock, presumably a silicon based clock, may be ceramic, not as good as a Xtal clock.
All I could find:
Maxim chips silicon based clock with 2% accuracy.
Ceramic resonator said to be 0.5%.