This is a product a friend of mine has made and thought people here may be interested in it!
We took it on our hike of the JMT (and an ascent of Mt Langley) and it was pretty sweet....
http://code.google.com/p/backwoods-logger/
The Backwoods Logger is a programmable device for measuring and graphing temperature, air pressure, and altitude. It's designed for hikers, backpackers, climbers, skiers, trail runners, cyclists, kayakers, snowmobilers, horseback riders, and other outdoorsy people interested in environmental data logging over timescales from an hour to a few weeks.
Features
Graphs of temperature, pressure, and altitude over time
Three graph time scales: past 2 hours, past 10 hours, past 2.5 days
Current rate of ascent/descent
Estimated time of arrival at a user-defined altitude
Weather forecast
Station pressure and pressure at sea level
Snapshot feature – make a permanent record of date, time, altitude, temperature, and pressure at important waypoints
Current date and time display
Imperial or metric units option
Battery voltage indicator
Sound on/off control
3 to 6 month battery life, depending on usage
Temperature measurements in 0.5 degree steps, from -10F to 117.5F (-23C to 48C)
Air pressure measurements in 0.01 in-Hg steps, from 5.9 to 36.12 in-Hg (170 to 1250 millibars)
Altitude (calculated from air pressure) measurements in 2 ft steps, from -1384 ft to 14999 ft (-300 to 4500 meters)
Download graph data to your PC using the optional Blsync adapter
