Came here to say this. If you load your presentation to Drive you're in full control and only need to take the stick and your phone! SICK!
It's like an HDMI usb stick. HDMI doesn't conduct power so you have to charge them and for the $35 it's cheap enough to throw away if you don't dig it. Along with power it requires a TV so not perfect for your answer but I'd carry one everywhere. (and will by next week)