GPS on Bicycles
The bike - Ryan Vanguard long wheelbase recumbent with underseat steering. (= No handlebars to mount stuff on)
What I am using right now
A Garmin eTrex Vista HCX in a RAM mount. The RAM mount clamps to the top tube between my knees.
What I envision
For short rides, a data logging GPS without any map display.
Display: current speed + trip distance
A wheel sensor for detecting when the bike is moving so that the GPS will power down when I stop and power back up when I start moving. Wheel sensor does speed indication and Dead Reckoning when the GPS does not have lock.
Wheel circumference is auto-calibrated by the GPS.
A button to power up GPS on demand.
Bluetooth for upload / download. A button to initiate data transfers. GPS could initiate bluetooth connection; when it senses we have returned home from a trip it would attempt to connect.
A 12v power system made up of 12 AA NiMH cells.
LED headlight and taillight.
Bill Cotton's notes on using Garmin GPS receivers on a drop bar bike