Personal Project

LoRA Messenger

I started this project with the goal of learning how to use the ESP32 microcontroller. With help from YouTube and ChatGPT, I created "Brolocator", a device that lets you send messages over long distances without internet. It can also perform crude full-duplex 2-way voice transmissions within range of ESP-NOW.

Built with

GitHub Demo video 3D model

Demo Video

Functionality

Use LoRA for long distance messaging
2-way voice communication when in range of ESP-NOW
Powered off rechargeable LiPo batteries
2 displays
A mode for range testing
Decent and simple to use UI

The two radios trade off against each other: LoRa reaches kilometres but only carries text a packet at a time, while ESP-NOW is a short hop that is fast enough for live voice. Try the link below to feel the difference.

You

PICK A MESSAGE“On my way, give me 10”

Friend

STANDING BY···

Pick a message

LoRa

RangeKilometresopen ground, line of sight

CarriesOne slow packet at a time

Long, lazy radio waves trade reach for bandwidth, so messages travel far but arrive a character at a time.

ESP-NOW

Range~150 metresthrough a wall or two

CarriesLive, two-way audio

A short, direct hop between the two ESP32 radios keeps latency low enough for real conversation.

Project Development

Brolocator is my first deep dive into microcontrollers, and also my first attempt at designing a PCB. I used PlatformIO to code the ESP32, and with some help from YouTube and ChatGPT, I was able to learn how to use each component to build the Brolocator.

Code

Based on my research, PlatformIO was the best choice for developing code for the ESP32. You can download the PlatformIO project files below.

PlatformIO Project FilesDownload the full PlatformIO project for the Brolocator ESP32 firmware.

Download Project

Brolocator on GitHubThe full source for the Brolocator firmware, hosted alongside the PlatformIO project.

View GitHub Repo

PCB Design

I used KiCAD to design a PCB for all the components. You can download the KiCAD files below.

KiCAD schematic for Brolocator PCB — Schematic

KiCAD PCB FilesDownload the full KiCAD project for the Brolocator PCB design.

Download KiCAD Files

3D Design

I used Onshape to design a case for the board. You can get the files and view a live preview of the model below.

Design iterations for the Brolocator case — Design iterations

Design failures and lessons learned — Learning from design failures

Onshape 3D ModelView the live interactive 3D model of the Brolocator case on Onshape.

View on Onshape

Assembly

Assembly of all components together.

All components soldered to the PCB and working

Fitting PCB into the case — Fitting PCB into case

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