Just a short post.
1) AMS made a nice lightning sensor chip AS3935
2) Jayson Tautic from TAUTIC ELECTRONICS LLC made even nicer breakout board
3) I made Arduino library to make use of AS3935 easy on this ever so popular platform
4) and tested it on Arduino Mega 2560 and chipKIT MAX32
The code (hopefully) works with most of original boards and clones.
Here is the link again, just in case you missed it – https://github.com/raivisr/AS3935-Arduino-Library