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LoRa / Meshtastic mesh — canonical radio config

The Scottina mesh: stock Meshtastic firmware + this one config, identical on every node. This file IS the "note the choice so all nodes match" record — if a value here changes, it changes for the whole roster at once, via tools/provision_mesh.sh.

Scope: diagnostics only. The E-Stop LoRa diagnostic is a separate raw-radio firmware on its own band (EByte 433) and is deliberately not part of this mesh — nothing here touches it.

The pinned radio config (every node, no exceptions)

Setting Value Why
Region EU_433 The T3s are the 433 MHz hardware variant; EU_433 is Meshtastic's 433 band plan. A 433 front-end set to US-915 transmits nothing (bench fact 2026-07-17 — cost a full e2e run). Region/band mismatch = silent no-mesh, the #1 bring-up failure. Verify first, always.
Modem preset LONG_SLOW Alerts + short commands, not streaming: the slow preset buys link margin over water. Must be identical everywhere — a preset mismatch is as dead as a region mismatch.
Firmware stock Meshtastic ≥ 2.5 2.5+ gives PKI remote admin (Prime governing the sensor node over the air).

Channels (PSK-encrypted, purpose-separated)

Slot Name PSK Purpose
0 (primary) ScotTel TEL_PSK in mesh-secrets.env Telemetry + pager: sensor metrics, CAN-trigger alerts from Light's companion.
1 (secondary) ScotCmd CMD_PSK in mesh-secrets.env Command plane only (MICROKVM-PROTOCOL.md). Its PSK membership is the coarse auth boundary around execution — never shared with sensor chatter, never given to a node that doesn't command.

PSKs are 256-bit, generated once by tools/provision_mesh.sh into /opt/kilodash/mesh-secrets.env (git-ignored, per-boat). Which node carries which channel:

Node ScotTel ScotCmd
Prime radio (T3 #1) ✔ ✔
Sensor node (T3 #2) ✔ —
Light's companion (ESP32) ✔ —
Pager/commander (phone) ✔ ✔

Expected node IDs (fill in at bench bring-up; the ScotCmd column feeds config.json → microkvm.allowed_nodes):

Node Node ID On ScotCmd?
Prime radio !ea244ad4 (BLE E8:6B:EA:24:4A:D6, TLORA_V2_1_1P6 433 MHz, fw 2.7.26) yes (the executor's own radio)
Sensor node "Kate" !ea245c80 (BLE E8:6B:EA:24:5C:82, TLORA_V2_1_1P6 433 MHz) yes — dual duty: sensor node AND the phone's pager/commander seat until a dedicated commander radio exists; her ID is in microkvm.allowed_nodes. Owner name kept as "Kate (KATE)" (deliberately named — the roster's "Scottina Sensor" was a placeholder).
Light companion !________ no
Phone rides Kate (no radio of its own) via Kate

E2E proven 2026-07-17: status / snap answered and tile correctly rejected disarmed over the air (Kate → LoRa 433 → PRIM → BLE → executor); remote admin read of Kate's telemetry interval via PRIM with the PKI admin key. When a dedicated commander radio arrives: move ScotCmd + allowed_nodes membership off Kate.

Prime radio public key (2026-07-16, feeds the sensor node's security.admin_key for over-the-air admin): C+JFlde3fGzpUUMgVGRsDgbsraZwbmcG+BG3FsOfr2s=

Node roster + names

Set names deliberately before deploy — never ship the MAC-default cosmetic name (the CanTick naming trap).

Node Long name Short Role
T3 #1 Scottina Prime Radio PRIM BLE-linked to Prime; carries the command plane and relays pager/telemetry. WiFi off — Prime's WiFi is reserved for the web app; this node talks BLE only.
T3 #2 Scottina Sensor SENS Standalone; exposed I2C port for drop-in sensors, remote-governed from Prime over the air. Doubles as Light's temporary UART companion during bench work.
ESP32 + LoRa Scottina Light Companion LGHT Wired to Scottina Light over UART, Serial module in TEXTMSG mode. Light (SAMD51 — cannot run Meshtastic itself) formats CAN-trigger strings; this node puts them on ScotTel.
Phone (Meshtastic app default) — Pager (alerts in) + off-grid commander (canned command frames out).

Sensor node specifics

  • telemetry.environment_measurement_enabled true — Meshtastic auto-detects supported I2C sensors at startup: plug into the exposed I2C port, reboot the node, confirm it appears. Power metrics likewise (power_measurement_enabled) for voltage/current sensors.
  • Send interval: 1800 s (30 min) default — airtime is shared and duty-limited; loose telemetry starves the alerts and commands that actually matter. Tighten deliberately, per sensor, not by habit.
  • Remote admin from Prime: the sensor node's security.admin_key is set to the Prime radio's public key, so Prime can enable/disable telemetry and change intervals over the air (meshtastic --ble <prime> --dest '!<sensor>' --set …). That's the "adequate user control" path for drop-in sensors.
  • Exotic (unsupported) sensor → Meshtastic custom-I2C firmware boilerplate; that's a firmware sub-task, only if a real sensor forces it.

Light's companion specifics

  • Serial module: serial.enabled true, serial.mode TEXTMSG, 38400 baud; RX/TX pins per board silk (script defaults GPIO 13/14 — check before wiring).
  • Wire Light ↔ companion UART crossed (TX→RX both ways), common ground.
  • The trigger-string format (short key=value pairs, one line) is the Light→mesh contract; it lives with Light's CAN trigger logic — keep both ends pointing at the same note so they don't drift.
  • Bench shortcut: T3 #2 can serve as the companion (same config, UART broken out) until the dedicated ESP32 exists — then move it, and re-check names.

Pager (phone)

  • Join both channels by QR from the Prime radio (provision_mesh.sh qr).
  • Alerts that matter → DM to your node (delivery-acks); broadcast is for the merely-informative. Save command frames as canned messages.

Bring-up order (per node)

  1. ⚠ ANTENNA BEFORE POWER — always. Transmitting into an open load can cook the PA. Bench habit, not optional.
  2. Flash stock Meshtastic (web flasher), plug into the Pi by USB.
  3. tools/provision_mesh.sh <prime|sensor|companion> --port /dev/ttyACM0
  4. Verify: meshtastic --port /dev/ttyACM0 --info → region US, preset LONG_SLOW, expected channels; record the node ID in the table above.
  5. End-to-end sanity: phone → ScotCmd → Prime radio → BLE → status reply (executor side: MICROKVM.md); sensor metric visible on phone; Light trigger string arrives as text.

Prime-side tiles (cross-refs)

  • Telemetry/pager metrics as kilodash tiles: autopopulate when streamed, with a freshness indicator (reuse the Signal K freshness pattern — LoRa is slow and bursty; live-vs-stale matters more here than on a wired bus). Not built yet — tracked in To-DoLists/LoRa-Mesh-Nodes-Setup.md.
  • The command-plane tile (armed/dormant + session log) ships with MICROKVM.md.

Known gotchas (the short list that costs evenings)

  • Region/preset mismatch = silent no-mesh. Check both, on every node, before debugging anything else.
  • SAMD51 can't run Meshtastic — that's why Light has a companion; no "just flash Light" shortcuts.
  • Channel PSK is the auth boundary. Command channel: separate, strong, never on sensor nodes.
  • Airtime is duty-limited. Default intervals long; tighten deliberately.
  • Antenna before power. Repeated because it kills hardware.
  • Names before deploy. MAC-default names are how you end up with three nodes called Meshtastic 4f2a.