I’ve been working on Particle devices, specifically trying to build RFM69 gateways with them for battery-powered sensors. This cool guy forked the LowPowerLab.com library for use with the Particle Photon, which works perfectly. However, I want to use the Particle Boron, which is an LTE-enabled microcontroller (I can’t access wifi where it’s meant to be deployed). The Boron is a 3rd Gen Particle device and is does not compile with the aforementioned library, which stinks (and I’m not knowledgeable enough on RFM69 to fix it). But – I am able to use an RFM69 breakout with an Arduino Nano, and I am able to have the Nano communicate with the Boron via serial – so, I chained them up that way. And it works!
So the impetus for all of this is that I need a reliable (and enterprise-friendly) backend to sensor networks, and Particle seems really great. But, I need my sensors to be able to run on batteries (a wall plug isn’t always available) for a long time and be able to communicate readings back from a decent distance while still not using much energy from the batteries (RFM69 is good in this regard, wifi is bad, both on energy and distance). I am using Moteino right now for the sensors (although the idea is to eventually create custom PCB’s). The sensor below is using a VL53L0X breakout to measure distance – in the previous screenshot you can see the data being transmitted:  (node #) 30.00(mm distance), -32 (RSSI). When the sensor is actually in the field, it won’t have the FTDI connector, it’ll have two lithium AA’s.
I realize that this isn’t any great breakthrough, but I was pretty happy that I can now deploy the gateway and maybe attack the library issue later.