guys, anyone knows how to build/DIY a USB OTG but capable of charging the phone at full fledged 2.1amp? Not necessary need MHL but I need it to connect to a USB hub. Major will be USB-DAC, some USB peripheral to control the phone. Hope sifu here can shed some light.

Means opt for custom kernel is the only solution? I've found the below links but it's too complicated. I'm asking this because I try to charge my phone using the car adapter (cigarette adapter rated 2.1a), the phone discharges slowly when i use waze or other gps software. I'm looking for solutions to prob this problem. Charge the phone while using.

http://forum.xda-developers.com/showthread.php?t=1953061

Thanks guys. yeah. I'm planning to tap the audio out via DAC at the same time charge the phone. Phone got tonnes of song and updating the libraries on the phone is much better than using USB on the head unit.

I'm eager to work on method 2 but as always, no base line electronic knowledge. Some told me arduino is probably my best bet. Hope some of you can share a bit of knowledge.cheers

What's the best barometer app? comes with weather alert. if got widget even better.