A non-USB router : Atmega + MP3 audio decoder ?

[KevinGartner]

Hello !

I have read mightyohm's article about building a DIY wifi radio, and I found that really amazing, interesting and instructive !
I did some researches of electronic solutions for a Wi-Fi DIY system connected on an AVR (Atmega128 for exemple), but I abandoned when I saw it was very difficult to get chips like basebands from electronics producers, and above all when I saw that little Wi-Fi modules for microcontrollers cost more than a complete wifi router !...


I would like to do a similar project .. I haven't bought any wifi router yet, and I had a question about this :

If my router hasn't any USB port, do you think I can route the audio data (from the streaming radio server) from the main chip of the router to an Atmega128 (or other Atmega; this audio data would be routed through the router 4-pin serial port, to the RXD pin of the Atmega), then to a chip like VLSI VS1011 (MP3 audio decoder, who costs about 15-20$) by SPI bus ?



This MP3 decoder so could replace the USB audio card you put in your wifi radio.. But I am not expert enough to understand if it is technically possible to route audio data like this!

If you had a few minutes to spend with my holiday-amateur-project, it would be really great and I would be very happy of that

Thanks in advance

[mightyohm]

Interesting idea!

I wonder how much data processing you would need to do to a shoutcast stream before sending it to the MP3 decoder IC? Potentially not much...

Another approach would be to decode the MP3 data on the router, and somehow turn the audio output into a serial data stream. But I'm not sure if you could get enough bandwidth on the serial port to recreate the audio with reasonable fidelity.

[Sonny80]

Hi,
Few month ago I've played with DIY internet radio receiver based on ATmega16+vlsi1053b+enc28j60...
You can view details on my web page http://alyer.frihost.net/ethradio/eth_radio_en.htm
16MHz ATmega is enough for playing, but more SRAM will give better results.
Next version is based on ATxmega32A @32Mhz is much better.
I don't have an aim to add WiFi functionallity, 'cause not find any Wifi chip ready to connect with Atmega but I think it can be some Wifi router with bridge mode.

[LloydEwing]

Sonny,
Your internet radio project is very interesting! Was it less expensive than building a radio based on router hardware? Do you plan to develop it into a project that someone else could copy? I hope you will let us know about your progress.

Lloyd

[Sonny80]

In Russia new Asus WL-520gU is about $85. My device with LCD is about $40 with DIY PCB board (very hard work...) You can calculate the price for parts:

ATxMEGA32A4-AU TQFP - main MCU@32MHz
FM25V10-G - SPI RAM for MP3/TCPIP buffering
ENC28j60 - Ethernet chip
VS1053b -MP3/OGG decoder

If you need LCD then add WH1604A-YYH-CT price. And also you need some components as chip resistors, caps, xtals, sockets etc...
The most costly part is PCB.

Unfortunally the project is raw 'cause I have not enough time to working on it. I have one PCB radio and one protoboard version both working OK.

The current software can play only Shoutcast/Icecast formats both MP3 and AAC (really cool quality with low bandwidth)!!!

The software is open source and written on plain C (no OS is used) it used original embedded TCP/IP stack by Dmitry Oparin (RST7_cbsie) and have to be compiled by IAR AVR compiller (no GNU version will be available).

The development of this board was a hobby for me plus the desire to understand and touch the embedded TCP/IP solution (web server+client in one small 16MHz chip ) it took a lot of time just for radio listenning ))

At this time I build another Internet Radio Player based on ALIX.3D3 single board PC, with attached USB2LCD 20*4 module and USB IR remote control. I really like it!!! (no fan noice, it playing any audio format with Winamp) and powered up with 12V@2A source. You can install both Linux/Windows depending what you prefer. To add WiFi - just plug USB WiFi stick or PCI-e card.