We built 3 Single Channel Gateways(SCG) in San Diego but only one Things Uno nodes and want more. So I used the Arduino Mini-Sensor-HTU21 hardware guide to build up a node from an Arduino ProMini and an RFM95W radio board(US915).
URL to hardware wiring guide:
I found two LMIC libraries for use on Arduino 328 based boards but had to hack them for both the US 915MHz frequency and the fact we just have Single Channel Gateways(SCG). I forked the libraries, updated them for US915 and SCG use. I also tweeked the examples in the libraries and created new Single Channel Node(SCN) examples. You should be able to just open the new examples, add your TTN keys and upload to the SCN.
Those two libraries are on GitHub, one is a C and the other a CPP library.
C library: https://github.com/dlarue/arduino-lmic
CPP library: https://github.com/dlarue/LoRa-LMIC-1.51