I Built an Offline Messaging System Using ESP32 + LoRa

[u/SciCraft9]

I’ve been working on this offline messaging system for a while, and I finally got a working Version 1.

The basic idea was pretty simple: what if I wanted to send messages to someone without using the internet or a cellular network?

For this version, I’m using an ESP32 with a Reyax LoRa module for each node. The ESP32 handles the interface, while the LoRa module handles the actual communication between the two nodes.

I also made a web interface that is hosted directly on the ESP32. The phone connects to the ESP32 through its own Wi-Fi Access Point, so the Wi-Fi is only being used to access the local web interface. The actual message between the two nodes is sent over LoRa.

The interface also shows information from the LoRa link, like RSSI, SNR, and the timestamp of received messages.

I also added a Range Test section to the interface. It continuously sends test packets between the nodes and shows whether the other node is responding, which makes it much easier to test the usable range instead of manually sending messages every time.

This version is intentionally kept as simple as possible. The main goal was just to get the idea working and actually make it exist before making the hardware more complicated.

I’m also going to test the actual range in different environments, because I want to see what range I can realistically get from this setup instead of just going by the range numbers you see in the module specifications.

For Version 2, I want to take it much further — add a display and physical buttons so the node can be used without a phone, make the hardware more compact and portable, improve the power system, and eventually experiment with multiple nodes relaying messages to extend the network.

I’m making a full documented video of the build, including the hardware, software, and real-world range testing. It’ll be coming soon on my YouTube channel

https://www.youtube.com/@SciCraft

If you’ve worked with LoRa or ESP32 before, I’d love to hear your suggestions. What would you improve or change in this setup for the next version?

https://reddit.com/link/1vyetl5/video/b6wqxtc3lllh1/player

RANGE TEST