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wifiaudio:start [2015/12/23 14:01]
tschulz [Requirements]
wifiaudio:start [2018/11/12 14:01] (current)
tschulz [Transmitter]
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 ===== How it Works ===== ===== How it Works =====
-  * Essentially we are using NETCAT to pipe audio from a mic input on one computer to the audio output of another computer. +  * Essentially we are using **NETCAT** to pipe audio from a mic input on one computer to the audio output of another computer. 
-  * It appears that ssh adds a lot of latency around 1-2 secs which is not acceptable more most instances+  * It appears that **ssh** adds a lot of latency around 1-2 secs which is not acceptable more most instances
   * Netcat on the receiver need to starts before the transmitter starts to send otherwise the transmitter script will exit with a connection refused. ​   * Netcat on the receiver need to starts before the transmitter starts to send otherwise the transmitter script will exit with a connection refused. ​
  
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   * Obviously some sort of tcp/ip must be running to for the netcat communication to work.    * Obviously some sort of tcp/ip must be running to for the netcat communication to work. 
  
 +===== Wifi Setup =====
 +
 +<file bash /​etc/​network/​interfaces>​
 +...
 +auto wlan0
 +iface wlan0 inet dhcp
 +        wpa-ssid ssid
 +        wpa-psk ####
 +
 +...
 +</​file>​
 +
 +===== Audio setup =====
 +
 +  * By default the usb audio adapter is detected as card 1 not card 0(default). ​ I tried disable the bcm sound module but for some reason that disables the mixer of the usb audio adapter.
 +  * I was able to set the default card using asound.conf
 +
 +<file bash /​etc/​asound.conf>​
 +pcm.!default {
 +    type hw
 +    card 1
 +}
 +
 +ctl.!default {
 +    type hw
 +    card 1
 +}
 +</​file>​
  
 ====== Receiver ====== ====== Receiver ======
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 PORT="​8080"​ PORT="​8080"​
-RATE="5+RATE="2
-BUFFER="​50"+BUFFER="​10"
 FORMAT="​cd"​ FORMAT="​cd"​
  
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 ====== Transmitter ====== ====== Transmitter ======
 +  * **RECV_ADDR** will need to changed to something valid like a ip address or a hostname/​fqdn.
 <file bash wifi_audo_send.sh>​ <file bash wifi_audo_send.sh>​
 #!/bin/sh #!/bin/sh
  
 PORT="​8080"​ PORT="​8080"​
-RATE="5+RATE="2
-BUFFER="​50"+BUFFER="​10"
 FORMAT="​cd"​ FORMAT="​cd"​
  
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 arecord -B ${BUFFER} -r ${RATE} -f ${FORMAT} | netcat ${RECV_ADDR} ${RECV_PORT} arecord -B ${BUFFER} -r ${RATE} -f ${FORMAT} | netcat ${RECV_ADDR} ${RECV_PORT}
 </​file>​ </​file>​
 +
 +====== Audio Passtrough ======
 +  * Check mixer controls for input ampifcation if clipping occurs
 +<​file>​
 +arecord ​ -f S16_LE -c2 -r48000 -f dat | aplay -f S16_LE -c2 -r48000 -f dat
 +</​file>​
 +
 +
 +====== Price List ======
 +
 +[[https://​docs.google.com/​spreadsheets/​d/​1jROjZBKDP32I1MQKS9gV2c9oLo5q8K8QiZUgWr6fepo/​edit#​gid=333349986|Price List]]
 +
 +====== Parts List ======
 +  * Arm Computer
 +  * Wifi Adapter
 +  * Audio Adapter
 +  * Power Supply
 +  * Flash Card (Storage)
 +
 +====== Raspberry Pi Issues ======
 +  * I get this error whenever I try to change either the buffer size, buffer time, or interrupt period on both the R Pi 1 and R Pi 2<​file>​aplay:​ set_params:​1305:​ Can't use period equal to buffer size (256 == 256)</​file> ​
 +  * I picked up a C-Media CM108 Chipset usb audio adapter and it fixed the problem. ​ I able to adjust the sample and buffer size [[http://​www.amazon.com/​External-Adapter-Windows-Drivers-Needed/​dp/​B00V9E9YRG|Link]]
 +====== Other Notes ======
 +  * The "​Chip"​ microcomputer looks really promising it includes storage, wifi, and audio all on board and is selling for $9.  Their website says they will be shipping in June 2016 [[http://​getchip.com/​]]
wifiaudio/start.1450900862.txt.gz · Last modified: 2015/12/23 14:01 by tschulz