Well this guys build a wireless guitar interface, they talk about ~2.5 ms latency, 15 hours operation per charge. But it's expensive 430GBP. http://www.stagecl

Well this guys build a wireless guitar interface, they talk about ~2.5 ms latency, 15 hours operation per charge. But it's expensive 430GBP. http://www.stageclix.com/images/stories/PDF-Files/PerformingMusician_stageclix_review-2.pdf http://www.stageclix.com/images/stories/PDF-Files/Performing... But they are using basically $2 microcontorllers(from nordic semi) and a bit of analog electronics - so the potential for cost reduction is quite large.