Smartphone LoRa connection DIY

Software

Here's how to connect your phone to a LoRa module using standard components, along with an example chat program.

This project will help you create a connection between your phone and a LoRa module using the USB port and an Arduino Lilypad USB. There is an example chat app for point to point communication, and, you can modify it to make even a TTN sensor out of a smartphone :)

Step 1: Hardware

You can chose between these two Atmega32U4 3.3v 8MHz models, although the black one seems to be a little bit better, the blue one stops working sometimes with my black phone ...

It is important to use OTG cable adapters

Note about the PCB

there are 2 options, left or right

Choose one depending on what side you want to solder your chips

Since it is going to be in touch with your phone, I make use of a sandpaper and transparent tape to make it smoother and protect it from short circuits

there actually is transparent tape covering the contacts :)

Setup Arduino IDE for development

Code is hosted in github.com, it is open source, feel free to contribute, reporting bugs or making suggestions would be great :)

Download it and open:

ArduinoIDE/USBRFMApp/USBRFMApp/USBRFMApp.ino

Change Sketchbook location under file --> preferences

If needed add additional boards under file --> preferences... I've been using:

https://adafruit.github.io/arduino-board-index/package_adafruit_index.json

Now select your board under tools --> Board (maybe not the same as the picture, chose yours)

It should now compile, upload it to your board and configure it using the web interface

That's it, I hope it is clear enough... if you have problems, feel free to ask any question

Step 3: Custom App

If you want to get rid of the chat system and read/write raw bytes from/to the RFM module open the Android Studio Project, edit the following file and add your logic.

AndroidStudio/USBRFMApp/app/src/main/assets/USBRFMApp/app/App.js

I hope it is clear enough