Add tip to README

README.md

@@ -84,6 +84,12 @@ If you use the argument `-audio -`, Pi-FM-RDS reads audio data on standard input
 sox -t mp3 http://www.linuxvoice.com/episodes/lv_s02e01.mp3 -t wav -  | sudo ./pi_fm_rds -audio -
 ```
 
+Or to pipe the AUX input of a sound card into Pi-FM-RDS:
+
+```
+sudo arecord -fS16_LE -r 44100 -Dplughw:1,0 -c 2 -  | sudo ./pi_fm_rds -audio -
+```
+
 
 ### Changing PS, RT and TA at run-time