A rugged, solar-capable, dual-radio environmental telemetry node built on the Meshtastic + LoRa stack.
Submission: Seeed Studio Meshtastic Build-Off 2026
Status: Design complete & verified — routed, DRC-clean (0 errors), Gerbers exported. Pre-fabrication (first article not yet ordered).
Hardware revision: v1.0
License: Multi-license open source — CERN-OHL-S-2.0 (hardware), GPL-3.0-or-later (Meshtastic firmware variant), MIT (tooling). See LICENSE and NOTICE.md.
3D render (top). Bottom: assets/chameleon_mesh_node_v1_bottom.png. Renders are generated headlessly from the KiCad project via kicad-cli pcb render; the XIAO ESP32-C5 (U2) has no 3D model assigned and renders flat.
The Chameleon Mesh Node is a single-board, battery-and-solar-powered field appliance for long-duration off-grid telemetry. It joins a Meshtastic mesh on sub-GHz LoRa for resilient long-range messaging, reads local environment with an on-board sensor, and exposes a Wi-Fi / BLE side-channel for short-range provisioning and bulk-data offload.
Designed to be deployed once, walked away from, and forgotten about for months.
Most off-the-shelf Meshtastic nodes pick one path: a LoRa-only board that needs a phone to provision, or a Wi-Fi-only "smart sensor" that needs an AP within range. Neither survives a real off-grid deployment where the closest infrastructure is hours away.
This board pairs two complementary radio subsystems on one PCB:
| Subsystem | Role | Module |
|---|---|---|
| Long-range mesh | Meshtastic LoRa + GNSS time-sync + Wi-Fi scan for opportunistic uplink | Seeed Wio-WM1110 (Semtech LR1110 + Nordic nRF52840) |
| Local-area + provisioning | Wi-Fi 6 / BLE 5 / 802.15.4 for setup, OTA, and bulk data offload to a passing operator's phone | Seeed XIAO ESP32-C5 |
Both radios cohabit one ~60×40 mm 2-layer board, with explicit RF zoning and a shared ground pour designed to keep mutual desense within acceptable limits for an environmental-sensing-class duty cycle.
| Dimensions | ~60 × 40 mm, 2-layer FR-4 |
| MCU | Nordic nRF52840 (Meshtastic firmware host) + Espressif ESP32-C5 (companion) |
| Radios | Semtech LR1110 (sub-GHz LoRa, GNSS, passive Wi-Fi scan); Wi-Fi 6 / BLE 5 / 802.15.4 |
| Power input | USB-C 5 V / LiPo single-cell 3.7 V |
| Charger | Texas Instruments BQ24074 (USB-priority, solar-compatible up to 6 V VIN) |
| Battery connector | JST-PH 2-pin |
| Environmental sensor | Bosch BME280 (temperature, humidity, barometric pressure, I²C) |
| Quiescent target | < 50 µA in deep-sleep between Meshtastic transmissions |
| Operating temperature | -20 °C to +60 °C (designed; pending environmental test) |
chameleon_mesh_node/
├── README.md — this file
├── LICENSE — multi-license map (see also LICENSES/, NOTICE.md)
├── LICENSES/ — full license texts (CERN-OHL-S-2.0, GPL-3.0, MIT)
├── NOTICE.md — third-party attribution
├── SUBMISSION_CHECKLIST.md — Build-Off submission readiness gate
├── assets/ — 3D renders
├── docs/
│ ├── architecture.md — block diagram, radio zoning, antenna feeds
│ ├── build-guide.md — BOM, assembly notes, first-power-on checklist
│ └── power-design.md — solar input, charger, fuel-gauge, sleep budget
├── hardware/
│ ├── kicad/ — KiCad 10 project (schematic, PCB, footprints, gerber zips)
│ ├── gerbers/ — extracted v1.0 Gerbers + Excellon drill (fab-ready)
│ └── scripts/ — Python composers that regenerate schematic + PCB from source
├── firmware/ — Meshtastic nRF52840 variant (variant.h + platformio.ini) + ESP32-C5 stub
└── enclosure/cad/ — 3D-printable case (planned, post-fab)
The KiCad project is fully regenerable: python3 hardware/scripts/build_schematic.py rebuilds the schematic from the Python composer, and python3 hardware/scripts/build_pcb.py rebuilds the pre-placed PCB. You can wipe the .kicad_* files and reproduce the design from source.
The Chameleon Mesh Node is a Meshtastic node. The Nordic nRF52840 core of the Wio-WM1110 runs the Meshtastic firmware; the Semtech LR1110 is its sub-GHz LoRa radio (plus GNSS time-sync and passive Wi-Fi scan). It joins a Meshtastic mesh, announces itself, relays messages, and publishes its BME280 environmental readings as Meshtastic telemetry — provisioned over BLE with the standard Meshtastic mobile app.
Because the base board (Seeed Wio-WM1110 / nRF52840 + LR1110) is already supported
upstream, this project ships as an incremental hardware variant, not a new port.
The board-specific deltas (BME280 at I²C 0x76, an ESP32-C5 companion-wake GPIO)
are captured in firmware/variant.h +
firmware/platformio.ini, layered on the upstream
Wio-WM1110 build environment. See firmware/README.md.
- Schematic ERC: 0 errors / 0 warnings (KiCad 10).
- PCB: routed (2-layer, GND-stitching vias), 3 GND zones poured, RF-zoned placement.
- Post-route DRC: 0 errors / 14 warnings (silkscreen/courtyard advisories on dense modules; reviewed and accepted — see
docs/). - Gerbers + Excellon drill exported (
hardware/gerbers/, also zipped inhardware/kicad/gerbers_v11.zip). - Board outline: ~60 × 40 mm, 2-layer FR-4; RF-zoned placement (radios on opposite edges) over a shared GND pour.
- Schematic netlist + ERC clean
- PCB placement (RF-zoned) + routing + GND pour
- DRC clean (0 errors) + Gerber/drill export
- 3D render verification (headless)
- Order first-article prototype (JLCPCB / PCBWay)
- Bring-up: power smoke test, Meshtastic flash (SWD), mesh-join test
- Measure deep-sleep current vs. <50 µA target
- Upstream the Meshtastic variant (PR to meshtastic/firmware)
- Enclosure CAD
Multi-license open source — see LICENSE for the per-component map and
LICENSES/ for full texts. Hardware: CERN-OHL-S-2.0. Meshtastic
firmware variant: GPL-3.0-or-later. Tooling/generators: MIT. Third-party
components retain their upstream licenses (NOTICE.md).
- Seeed Studio for the Wio-WM1110 module, the XIAO ESP32-C5, and the Meshtastic Build-Off platform
- The Meshtastic project for the firmware and the mesh protocol
- Semtech, Nordic, Espressif, Bosch, TI for the silicon
- KiCad for the EDA toolchain (v10.0.3 used)
See repository issues for design questions, build reports, or fork notifications.