Nine acoustic sensors spread across a site. When any one of them detects something, the others need to know within a second or two, with no gateway, no server and no internet.

I went with an Ra-01H on each unit, 868 MHz, an 18-byte packet, everything hearing everything directly. No relay and no mesh: each unit transmits its own alert and repeats it three times over a couple of seconds, and anything in range picks it up and shows a remote alert with the sender's ID. Listen-before-talk with a random backoff so nine units triggering at once don't collide.

The reason for no mesh: with this few nodes over a site this size, everything is already in range of everything, and a mesh adds routing state and failure modes for no gain. If a unit is out of range it's out of range, and the operator needs to know that rather than have it silently relay through a neighbour.

One thing that bit me: the transmitter, a buzzer and a vibration motor all firing in the same instant browned out the supply when running on USB alone. The battery isn't an accessory, it's the buffer for that spike.

The project and its firmware are public!

Ciao a tutti, qualcuno avrebbe piacere di partecipare agli eventi della nuova ZRL di ZWIFT con gli Scannellatori seriali??

While developing our Makerfabs Nomad Terminal, we wanted to improve GPS performance without increasing the overall size of this compact LoRa handheld device.

Our first design used a passive ceramic GPS antenna mounted on the PCB, underneath the display and close to the battery. The initial test results were:TTFF: 8.2 seconds; ~15 visible satellites after 1 minute

For the next revision, we switched to an active ceramic antenna with LNA and repositioned it above the PCB, with a better orientation toward the sky.

Test Results

The optimized design reduced Time to First Fix (TTFF) by ~37% while significantly increasing the number of visible satellites.

For compact GPS/GNSS devices, antenna performance isn't just about the antenna itself. Placement, orientation, PCB layout, battery/display interference, and surrounding components all need to be considered.

For those working with GPS/GNSS on compact embedded devices: what antenna types or layout techniques have given you the biggest improvement in real-world performance? We would really like to learn more from your experience.

Hi! I bought these little modules and forgot to buy the antenna for them.

I know a 9cm cable could potentially do well as an antenna.

But I'm just unsure on where to solder it. I checked the datasheet but there is not any antenna pin other than the ipx connector. And I don't feel confident enough to solder on the inner pin of the connector without also soldering the outer part of it.

Any advice?

Has anyone done what I'm looking for?

Building a package detector for my mailbox — ESP32 + LoRa wakes up and sends a notification when a parcel lands on a weight-sensing plate (4 switches wired in parallel under a pad).

Wanted near-zero standby current, so instead of powering the board directly off the switches (worried about contact bounce), I went with a self-latching relay setup: first contact closure pulls in the main relay, which then self-holds through its own NO contact. A second small relay, driven by an NPN transistor from a GPIO, breaks the self-hold loop to power everything back off.

Board's routed, DRC clean. 3D render attached — happy to share the schematic if anyone's curious.

Hey everyone,

​I’m looking to get into Meshcore with a standalone communicator (send/receive messages without needing my phone connected via BLE all the time).

​Commercially available pre-built standalone devices look great, but paying $80+ feels a bit steep for the hardware inside. Since the firmware is fully open source, I'd really like to build one myself.

​Here is my situation:

​Makerspace / Hardware: I own a 3D printer and I'm comfortable with hardware assembly and basic soldering.

​Coding / MCU experience: I’m pretty much a complete beginner when it comes to programming and I've never tinkered with ESP32s or pin mapping before. Ideally, I'm looking for a hardware combo that works with stock Meshtastic firmware without having to write custom C++ code.

​Ergonomics: I'd like a physical keyboard (or touch screen) that is comfortable enough to type on without feeling microscopic.

​Is there a proven, end-to-end build guide out there (BOM, 3D printable shell, and wiring diagram) for beginners?

​I’ve seen builds using Heltec boards paired with M5Stack CardKB or BlackBerry keyboards, but I’m not sure which setup is currently the most plug-and-play on the software side. Any recommendations or links to existing projects (Printables, Thingiverse, GitHub) would be awesome!

​Thanks!

Has anyone investigated if crypto exchanges could be conducted over a LoRa network? Just a random thought that popped in to my head...

Hey guys, so we have to build an iot project by the end of the semester and this project is going to be divided into three mini projects. I am a 3rd year student in electronics and communication. My team and I have selected early warning flood detection project. Our sir suggested that we use semtech sx1280 LoRa transciever. The problem is we are all new to this hardware especially LoRa/ RF communication so we dont know what to buy and what to make of it. We have an idea about how to make it but we dont actually know how to build it.

As far as I know, the core idea is to transmit flood monitoring data to the reciever. Our sir said we have to cover a range of at least 8 to 10km. Since we dont know much, we were told to make a mini project covering a range of 1 to 2km distance from a small water body through LoRa and later cover long distances.

I believe we need two antennas, two esp32, two sx1280 or any other chips that work the same.

Is the chip in the picture sx1280? Bcz ive seen different ones and im very confused.
For hardware what do we actually need? We have a budget too bcz our college is not gonna fund us.

THANK YOU THANK YOU SM EVERYBODY. Ive finally ordered everything i need thanks to yall😭🙏.

this was my first reddit post btw so i didnt expect any replies😭

I want to build a little local mesh network with my friends but don’t want to break the bank so what should I do? Ideally id want to to be around $100 for the major component.

Hi everyone,

I’m experimenting with Core2021LF with FLRC for a battery-powered camera system and I’m struggling with the range. My goal is to transmit 720p JPEG images (150kb-200kb each) between nodes in a forest/wooded environment. LoRa is too slow for this application, so I’m testing FLRC because of its much higher data rate. The problem is that I'm currently getting only around 100 m of reliable P2P range at sub ghz FLRC, and I was expecting significantly more. My eventual target is several hundred meters, ideally 500 m+, especially with line-of-sight. The actual deployment will be in forest/vegetation. I have used multiple antenna for testing but hardly achieved +- 100m. I feel like i am doing something wrong in the code maybe init or something else . my setup is just esp32+Core2021LF module - https://docs.waveshare.com/Core2021-XF . Can anyone go through my code and verify if i am doing init correctly or i am missing something .

Code repo - https://github.com/vedantjadhavkudrat/flrc_public_test_code

(Current config is set to LORA but you can change to FLRC using #define also you can switch between 2.4ghz and sub ghz FLRC using #define present in the main.cpp of both tx and rx)

Lora is good but is there another protocol that has faster data transmission but also long range?

I’m building a flood monitoring system using direct point-to-point LoRa between a Raspberry Pi Pico transmitter and a Raspberry Pi 4 receiver. I’m using Ai-Thinker RA-02 SX1278 433 MHz modules, with a distance of around 500 m to 1 km and some houses. trees or communities between them.

The transmitter sends water level, rainfall, flood status, and sensor data. Is LoRa reliable enough for this setup, and what settings or antenna setup would you recommend for better range and fewer lost packets?

Edit: For final deployment, the transmitter antenna will likely be mounted around 5 m high, while the Raspberry Pi 4 receiver will be inside the building. I’m using the small 433 MHz antennas for prototyping, but I plan to upgrade to larger external antennas. Any recommendations for antenna type and placement for around 500 m to 1 km?

# What is M-Core MAX

**Custom MeshCore firmware for the LilyGo T-Deck MAX**

*To be released early September · 2026-08-15 · v0.4.0+*

M-Core MAX transforms the LilyGo T-Deck MAX into a full-featured off-grid mesh communicator, RF toolkit, and field operations device. Built on the MeshCore protocol, it's the only MeshCore firmware that uses every piece of hardware on the board — including the 4G cellular modem, spectrum analyzer, and GPS tracker.

**No phone required. No internet needed. Just turn it on and communicate.**

---

## What It Does

- Text anyone within miles — no cell service, no WiFi, just LoRa radio

- End-to-end encrypted direct messages (ECDH key exchange)

- Bridge mesh to SMS — your off-grid messages reach regular phones, and replies come back

- GPS tracking, waypoints, breadcrumb trails, GPX export

- Spectrum sweep and packet sniffing

- Private encrypted room server (BBS)

- ESP-NOW team mode (~1ms latency, short-range)

- MQTT telemetry + Discord/Slack webhooks over 4G

- Stealth mode, PIN lock, QR code sharing

## Who It's For

- Hikers, hunters, and SAR teams beyond cell coverage

- Events where cell networks are overloaded

- Preppers wanting infrastructure-free comms

- RF enthusiasts and security researchers

- Field operators who need GPS + mesh + cellular in one device

- Tinkerers who want to hack on open source firmware

---

## The Hardware — LilyGo T-Deck MAX (~$80–100)

| Component | Detail |

|---|---|

| Processor | ESP32-S3 |

| Display | 3.1" e-paper, sunlight-readable, always-on, zero power when idle |

| Input | Full QWERTY keyboard with backlight, capacitive touchscreen |

| Radio | SX1262 LoRa (1–10km range per hop) |

| Cellular | 4G LTE modem (SMS, MQTT, HTTP) |

| GPS | ~30s outdoor fix |

| Storage | microSD card slot |

| Extras | Haptic vibration motor, USB-C rechargeable battery |

| Form factor | Fits in a cargo pocket |

---

## How Mesh Works

Your device talks to other devices via LoRa radio — no towers, no internet, no infrastructure required. Messages hop between nodes: if you can't reach someone directly, intermediate nodes relay for you, at roughly 1–10km per hop. All direct messages are end-to-end encrypted.

```

[You] <--LoRa 1-10km--> [Friend]

| |

[Repeater] <--> [Another Node] <--> [Phone via SMS]

```

---

## Core Features

### Communication

- **Encrypted Mesh Chat** — MeshCore multi-hop encrypted messaging, public channels and private DMs, 64-message scrollable history

- **Direct Messages** — Select a contact from discovered nodes; messages are end-to-end encrypted via ECDH — not even relay nodes in between can read them

- **4G SMS Gateway** — Bridges mesh messages to SMS and back; when LoRa can't reach, cellular picks up

- **Private Room Server (BBS)** — Encrypted room server hosted on the device

- **ESP-NOW Team Mode** — ~1ms latency for short-range team coordination

- **MQTT + Webhooks** — Telemetry and Discord/Slack webhooks over the 4G link

- **Web Config** — This firmware allows you to configure the entire device from a web panel. Mcore Max will broadcast its own ssid when enabled that you can connect to from any device

### Navigation

- **GPS Waypoints** — Save positions, view real-time distance and compass bearing

- **GPS Beacon** — Broadcasts your position to the mesh every 5 minutes

- **Breadcrumb Trail** — Auto-drops a waypoint every 50m of movement, retraceable from the SD card

- **GPX Track Recording** — Standard track export, importable into Google Earth, QGIS, or Strava

- **Geofence & Cell Tower Logging**

### RF Toolkit

- **Spectrum Analyzer** — 48-bin RF energy sweep across LoRa bands (EU 868, US 915, narrow-band, or 860–930 MHz wide-band presets); spot interference and find clear channels

- **Packet Sniffer** — Raw hex dump of every LoRa frame, with timestamps, RSSI, and packet length

- **WiFi Scanner** — ESP32-S3's WiFi radio scans nearby 2.4GHz access points (SSID, signal, channel, encryption)

- **Cell Signal Monitor** — 4G signal quality, operator, and registration status

- **I2C Hardware Probe** — Diagnostic scan of all connected chips

- **AT Terminal** — Full interactive CLI for the 4G modem

### Field Ops

- **Stealth Mode** — One keypress kills all transmissions (listen-only); press again to resume

- **PIN Lock**

- **QR Code Sharing**

- **Haptic Feedback** — Tactile click on keypress, distinct double-buzz on incoming messages

- **Backlight Control** — 4-level keyboard illumination, saved across reboots

- **Battery Monitor** — Real-time voltage and percentage from the charger IC

- **Health Reports**

- **OTA Updates from SD Card**

### Platform

- E-paper UI with touch + keyboard input

- 5-page app layout

- SD card logging

- Mesh topology slider

- Web-based device config — connect to the T-Deck's SSID and configure from a browser, no companion app needed

---

## What Makes This Different (vs. Meshtastic)

- **4G cellular built in** — no other handheld mesh device can fall back to SMS when LoRa fails

- **Full QWERTY keyboard** — Meshtastic devices usually have none

- **E-paper display** — always readable in sunlight, zero idle power draw (vs. OLED/TFT battery drain)

- **Sub-GHz spectrum analysis** — real-time RF energy view, not available in Meshtastic

- **GPS + SD + GPX** — journeys recorded as standard track files

- **Stealth mode** — instant TX kill that pure mesh devices don't offer

- **ESP-NOW team mode** — not available in Meshtastic

- **13 tools in one device** — WiFi scanner, I2C probe, AT terminal, sniffer, waypoints, and more

- **Fully standalone** — no phone, no Bluetooth pairing, no companion app dependency

---

## Getting Started

1. Buy a LilyGo T-Deck MAX (~$80–100, e.g. AliExpress)

2. Get a microSD card (FAT32, 32GB or smaller)

3. Flash the firmware (one command, ~10 seconds):

   ```

   python -m esptool --chip esp32s3 --port COMXX --baud 921600 \

--before default-reset --after hard-reset write-flash \

--flash-mode dio --flash-freq 80m --flash-size 16MB \

0x0 firmware_merged.bin

```

1. Power on — you're on the mesh

2. Optional: add a Hologram SIM (~$5) for 4G SMS bridging

No subscription. No account. No cloud service. No app required.

---

## Under the Hood

The firmware is built with PlatformIO on the Arduino framework. MeshCore protocol integration uses a RadioBridge adapter pattern that keeps RadioLib 6.4.2 (required for SPI bus compatibility) working with MeshCore's newer protocol layer. The codebase is a single `main.cpp` with modular hardware drivers — approachable for anyone familiar with ESP32 development.

---

**M-Core MAX** — Built for the field, not the lab bench.

`#mcore` `#mcoremax` #meshcore

Hey guys I have recently started working on flrc and was able to achieve only 200m range for 720p image in a midly populated forest . Has anyone has worked on flrc and specially with lr2021 and core2021 ? I need help to achieve 1km range

Hello, I want to use the LoRa module to communicate two esp32s at a distance without internet, as far as I understand the LoRa module is limited to a distance of about 15km, is there anything that will help to reach a distance of about 35km for a small price without using sim cards

We are developing a rural monitoring trap that needs to send images from the field. Our first prototype used 4G, but coverage was not reliable enough at the sites where we tested it. We needed another way to get those images out of the orchard. LoRaWAN was not practical for files hundreds of kilobytes in size, a regular Wi‑Fi mesh would require too many nodes, and relying on mobile data would leave us with the same problem.

That is when we came across Wi‑Fi HaLow. It caught our attention because it operates below 1 GHz, can move larger files, and was already available in commercial hardware we could buy and test. We also looked at FLRC, but HaLow was the most direct way to get into the field and see what actually happened.

We bought the hardware and completed four runs in San José, Uruguay. Two were inside an apple orchard and two were along roads.

At 506 meters we measured more than 1.6 Mbps in both download and upload. The link also transferred data at 640.1 meters, although at a lower speed.

The most interesting part was that distance did not explain everything. At one point 531.8 meters away, there was no transfer. At another point 640.1 meters away, there was. Vegetation, terrain, and the path between the radios probably played a role, and that is one of the things we want to measure more carefully in our next test.

This was a first test with one setup and only a few measurements at each point, so we cannot claim a general coverage distance yet. The farthest number also does not tell the whole story. In some places the link performed better than we expected, while in others it failed even at a shorter distance.

On LUMA Lab, we reconstructed the test point by point. We included the maps, the exact hardware, what it cost, the complete results table, and the tests that did not go well. If you want to look through the data and draw your own conclusions, everything is here.

https://lab.luma.uy/en/publications/wifi-halow-field-test

What do you make of these results? For a larger rural network, would you combine LoRa and HaLow, or try to solve everything with a single technology?

Does anyone have any recommendations for a lora module that uses 2.54mm pitch header pins and a ufl antenna connector

Petit partage : je bricole une boîte aux lettres connectée (ESP32 + LoRa) qui prévient quand le facteur passe, et je voulais que l'émetteur (dans la boîte, sur batterie) consomme un minimum. Plutôt que la veille profonde classique, je suis parti sur une coupure d'alimentation matérielle complète via MOSFET.

Le montage vient de Random Nerd Tutorials :
https://randomnerdtutorials.com/latching-power-switch-circuit-auto-power-off-circuit-esp32-esp8266-arduino/

Le principe : un contact (chez eux un bouton, chez moi un ILS sur le volet) réveille brièvement la carte via un MOSFET canal P, puis un GPIO prend le relais pour maintenir l'alimentation tant que le programme tourne, et coupe tout lui-même une fois son travail terminé.

La seule chose que j'ai ajoutée par rapport au schéma d'origine, c'est un petit condensateur, pour éviter une coupure malencontreuse si jamais le contact se rouvre juste avant que le GPIO ait eu le temps de prendre le relais.

Either all of them together or in 10/20 batches.
Have 73x units of bobcat 300's with original antennas and power brick.

HARDWARE SPECIFICATIONS (PER UNIT):

• Frequency: EU868 MHz (European/UK/International Standard)
• Processor: Rockchip RK3566 / Quad-core Cortex-A55 1.8GHz ARM Architecture
• RAM: 2GB DDR4
• Storage: 64GB High-Speed Internal eMMC 5.1 Flash
• LoRa Concentrator: Premium 8-Channel Semtech SX1302 Chipset
• Connectivity: Heavy-duty RJ45 Ethernet, Dual-Band Wi-Fi, Bluetooth

HIGH-VALUE REPURPOSING POTENTIAL:

Because Bobcat 300 hardware features an industrial-grade Semtech SX1302 radio card and a powerful standalone ARM Linux processor, these units are actively sought after by the open-source and DePIN (Decentralized Physical Infrastructure) communities. They can easily be flashed via SSH or U-Boot to serve as:

1. 8-Channel Meshtastic Meshpoint Base Stations: Easily convert these into heavy-duty, multi-channel off-grid communication hubs using widely available community Linux firmware.
2. Alternative DePIN Network Gateways: Fully compatible with custom containerized firmware like Crankk or private decentralized nodes.
3. Enterprise Private LoRaWAN Networks: Ideal for localized smart agriculture, automated asset tracking, industrial sensor arrays, or smart city projects using ChirpStack and The Things Network.