All the pro bikes at the USA pro challenge had a transponder attached to the non drive chain stay secured with zip ties, so if you must pose, zip a sensor on, lol.

I use cyclemeter with the IPhone Wahoo bike pack, speed/distance/cadence ($129) voice announcements, iPhone display off. I have gone for 2 hours on less than half battery. They also have an extended battery that mounts between the phone case and bike mount. I have to have my phone with me anyway.