Cavechat.org

Was looking at the Spark Electron kickstarter and thought this device would be very useful for cave communications. Imagine a scenario where one of these is hooked up to a ground station HF/LF radio and used to send/receive short messages. Then an in cave radio connected using an earth-current antenna to talk to the ground station could send/receive text messages and weather reports.

https://www.kickstarter.com/projects/sparkdevices/spark-electron-cellular-dev-kit-with-a-simple-data