Continuing my previous post on adding streaming audio from the ROV using icecast and darkice2 I have tried again! This time using a raspberry pi and a wolfson sound card that plugs in to the pi. It looks pretty good so far. The bad audio latency and buffer underrun problems I had before trying to pull from the webcam mic with the beaglebone are gone, and I boosted up the quality to 44khz and 128kbit. It will need a test streaming some music from an audio input like a CD player or Ipod though to really see what's going on but the delay is down to a little over 1 second from whistling in my kitchen to the onboard mics picking it up. I'm no vanderbelt so there could a nicer solution than adding a 2nd computer just for audio....but I really want audio for a more immersive driving experience for kids!
So how would you add this to the ROV? Well, if you shorten up the USB cable and clean things up a bit there should be plenty of room under the camera. I will have to do a fit test to see though. We will also need a switch or multi-port homeplug adapter so this audio server can run alongside the beaglebone black on the network. Mark has parts for this and says it should not be a problem. Eventually the ROV will be a whole computer network of it's own with multiple cameras on the network along side the control server and hopefully audio too if everything goes well!
To start with I would just want to use the onboard mics for simplicity sake, but then we could connect this to a hydrophone with some extra wires going through the endcap. So there's not much to see yet, but I am happy with this test and getting the darkice stuff to compile and get data from the wolfson mems microphones.
Thanks to Mark for parts.