WanderAway Family — Decision Log

Running log of every keep/swap/drop decision. Citations per entry. Emergency devices — reliability > all else.

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Stage 0 — Feature-parity sweep (2026-04-24)

• Decision: 4-tier family (Beacon Lite $89 / Trail $179 / Expedition $449-599 / Expedition Ultra $799) with shared platform + modular satellite-modem axis.
• Source: competitive audit vs Garmin inReach Mini 2, Garmin Messenger, ZOLEO, SPOT X, Apple iPhone Satellite, Motorola Defy Satellite, Bivy Stick, ACR ResQLink 400 PLB. See _COMPETITIVE-AUDIT-2026-04-24.md.
• Flags: Garmin inReach + Iridium partnership + GEOS dispatch is 15+ years mature; we are catching up not leading on satellite SOS pedigree. We lead on LoRa-mesh-as-baseline, open Meshtastic compatibility, no-subscription baseline, identity-aware safe-passage mode, 7-year parts, CC-BY-SA STLs.
• Lead axes: privacy + no-subscription baseline + survivor-aware protocols + open-protocol LoRa + Ambassador Signature + STL openness.
• Lag axes: Iridium global-network coverage (equal when we use Iridium, but Garmin's dispatch relationship has 15 yr of rescue-agency trust), brand recognition in rescue community, 2-way-messaging app polish (Garmin Messenger + Explore app are mature).

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Stage 1 — Intake + freeze (2026-04-24)

• Blueprint.am wanderaway_lora_node bundle preserved unchanged as ../wanderaway_lora_node/ (evidence, not design).
• Device IDs assigned: WV-SAFE-AWAY-LITE, WV-SAFE-AWAY-TRAIL, WV-SAFE-AWAY-EXPED, WV-SAFE-AWAY-ULTRA.
• Revision frozen: v1.0-candidate.
• Ship target locked: Lite + Trail 2027-Q2 · Expedition 2027-Q4 (pending Iridium contract) · Ultra 2028-Q1 (pending Astrocast contract).
• Blueprint reference build uses Heltec WiFi LoRa 32 V3 (ESP32-S3 + SX1262) + 18650 + 2W solar. We INHERIT: SX1262 LoRa, 18650 form factor, IP65 ASA enclosure, solar-charge architecture, external IP-rated antenna, cable-gland discipline. We REJECT: Heltec dev-board (not production-quality for emergency device), PIR motion sensor (wrong sensor class — WanderAway is personal-carry beacon not perimeter node), ESP32-S3 (not ultra-low-power enough for µA standby target; see §Stage 2 MCU decision).

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Stage 2 — Component selection (2026-04-24)

MCU — REJECT ESP32-S3, ADOPT Nordic nRF52840 primary + TI CC1352P7 alternate

Blueprint ref build used: Heltec WiFi LoRa 32 V3 (ESP32-S3 + SX1262). Works for sensor nodes.

Emergency-beacon reality-check: ESP32-S3 deep-sleep is ~10-150 µA but full-active is 20-300 mA. For an emergency beacon that must deliver 7-day standby in the field on a 2000 mAh cell, we need sub-µA standby + <10 mA active LoRa. ESP32-S3 is overkill on compute (dual-core LX7 at 240 MHz) and wrong on power envelope.

Better fit:

• Nordic nRF52840 — ARM Cortex-M4F @ 64 MHz, 256 KB RAM, 1 MB flash, 300 nA System-OFF standby, 5.3 mA TX, integrated BLE 5.3 (required for phone pairing in Mode 2), excellent Zephyr RTOS support. Field-proven in Meshtastic T-Beam / Heltec / LilyGO boards and Garmin-class devices. Primary choice.
• TI CC1352P7 — ARM Cortex-M4F @ 48 MHz, Multi-Band sub-1 GHz + 2.4 GHz radio integrated (could replace SX1262 entirely on some SKUs), 0.85 µA standby, proven in long-range sensor networks. Alternate for cost-reduced Beacon Lite.
• Nordic nRF5340 — dual-core (app + network), ultra-low-power, 700 nA standby. Considered for Ultra but nRF52840 is sufficient and better-supported today.

Decision: Nordic nRF52840 primary across all four tiers. TI CC1352P7 is alternate/second-source. ESP32-S3 rejected for production; acceptable for internal EVT dev-boards only.

Why: unified SDK + Zephyr + BLE + certified module path (nRF52840 is available as a pre-certified MDBT50Q module from Raytac — FCC + IC + CE cert passthrough saves $20-40k cert cost per region).

LoRa radio — KEEP SX1262 (from Blueprint)

Semtech SX1262 is the industry-standard LoRa radio for 2025-2026 designs. 150 dB link budget, -148 dBm sensitivity, 22 dBm TX. Used by Meshtastic, RAK, Heltec, LilyGO, and most commercial nodes. Decision: keep. Alternate: SX1268 (900 MHz China variant, not needed for US/EU).

CC1352P7 Multi-Band option: on Beacon Lite only, we optionally drop SX1262 and use CC1352P7's integrated sub-GHz radio to save ~$2.80 BOM. Trade-off: slightly less link-budget headroom + different RF front-end layout. Evaluate at EVT. Default: keep SX1262.

GNSS — ADD u-blox MAX-M10S (Trail/Expedition/Ultra)

Blueprint reference didn't include GNSS (sensor-node use case). WanderAway requires precise location for SOS + check-ins + breadcrumbs.

Menu (per _VALIDATION-AND-SENSOR-EXPANSION.md):

• u-blox MAX-M10S — L1 only, 12×12×2.5 mm module, 25 mW tracking, 12 µA backup, cold-start <25 s, <2.5 m CEP. Primary for Trail + Expedition baseline. Pre-certified. Cost ~$8.50 @ 1k.
• u-blox ZED-F9P — dual-band L1/L2 RTK-capable, centimeter-class. Ultra Lux option for survey / SAR professionals. Cost ~$170 @ 1k.
• u-blox NEO-M9N — L1 multi-constellation (GPS+GLONASS+Galileo+BeiDou), slightly better reception in canyons. Alternate to MAX-M10S. Cost ~$15 @ 1k.

Decision: MAX-M10S is primary across Trail + Expedition; Ultra baseline uses MAX-M10S with ZED-F9P as $+150 Lux option.

Satellite modem menu — CURATED FOR RELIABILITY

Emergency device — only include modems with real production history + proven ground networks + known resale terms.

Iridium 9603N (current) / 9670 (next-generation) — SELECTED for Expedition + Ultra.

• Iridium 9603N: SBD only, Short Burst Data, 340-byte MT / 270-byte MO messages. In continuous production since 2014. Garmin inReach uses 9602/9603. ~$175 BOM @ 1k.
• Iridium 9670: 2-way messaging + Iridium Certus 100 class (when paired with Certus transceiver). Available 2024+. ~$250 BOM @ 1k. Selected for Ultra 2-way messaging.
• Network: pole-to-pole global coverage, 66 active LEO satellites, proven since 1998. No single-point-of-failure concerns. Ground-station redundancy.
• Resale requirement: FCC Part 25 satellite service resale business license + Iridium airtime service provider contract (Ground Control / NAL Research / Satcom Global / Garmin own their airtime). BLOCKING.

Astrocast — SELECTED for Ultra as secondary satellite path.

• Astrocast-sat LoRa-based small-sat network (100+ satellites planned, ~20 operational 2026). Store-and-forward (not real-time). ~$45 BOM @ 1k.
• Use case: low-cost check-ins when user doesn't need real-time 2-way. Complements Iridium, not replaces.
• Resale: Astrocast SDK + service-provider agreement required. Not FCC Part 25 because Astrocast operates under its own framework — per ISED / FCC experimental/commercial authorization. YELLOW — needs validation by counsel.

Globalstar STX3 / ST100 — EVALUATED, REJECTED as primary.

• STX3: one-way simplex only (SPOT-class). 144 ms burst, no 2-way. Apple iPhone uses Globalstar via Apple's exclusive partnership; consumer-device resale terms outside Apple are unclear 2026.
• Decision: reject as primary; reserve as alternate for a future Simplex-only very-low-cost SKU if Globalstar terms open up.

Swarm M138 — FLAGGED, NOT INCLUDED.

• SpaceX acquired Swarm 2021. Swarm Tile / M138 still listed on some distributors 2026 but ongoing production + service-plan availability post-Starlink-Direct-to-Cell integration is unclear. SpaceX is merging low-cost IoT sat service into Starlink's DTC offering.
• Decision: do NOT include in v1.0 BOM. Re-evaluate after SpaceX publishes the post-acquisition Swarm roadmap (expected 2026-Q4 / 2027-Q1). Flagged "⚠ needs validation" in _VALIDATION-AND-SENSOR-EXPANSION.md.

Starlink Direct-to-Cell / Apple iPhone Satellite — NOT A COMPONENT CHOICE.

• These are consumer-phone satellite services, not modem modules we can embed. Referenced in competitive-audit only.

Power / charging / battery

Blueprint ref used: 18650 (3400 mAh) + TP4056 + 2W solar. We modify:

• Lite + Trail: 18650 user-swappable (2600-3400 mAh). Carries forward from Blueprint. Runtime target 7-day standby + 2 h continuous LoRa TX = met with 3000 mAh.
• Expedition: 18650 user-swappable + optional 2× 18650 for extended runtime. Same cell, higher count.
• Ultra: 18650 ×2 standard + integrated 2W monocrystalline solar panel (sapphire-glass covered). Solar extends runtime to "indefinite if ≥4 h direct sun / day."
• Charge controller: rejected TP4056 (no MPPT, inefficient for solar under partial shade). Selected TI BQ25798 solar MPPT charger for Expedition + Ultra (I²C configurable, up to 20 V input, integrated input FET). TP4056-class (BQ25180) retained for Lite USB-C-only.
• Cell chemistry: Li-ion (LCO/NMC) only. LiFePO4 considered for ultra-cold performance but gives up energy density; -40 °C discharge is supported by select Panasonic NCR18650-B variants.

Enclosure + materials

Keep from Blueprint: ASA for 3D-printed STL files (CC BY-SA for community). UV + temperature stable vs PETG/PLA.

Production: IP68 rating demands injection-molded glass-filled polyamide (PA6-GF30) or polycarbonate, NOT 3D-printed ASA. 3D-printed ASA housings are user/DIY path only (Standard 2, open STLs) — production Lite+Trail: PC/ABS injection-molded; production Expedition+Ultra: PA6-GF30 with overmolded TPE rugged-grip bumpers.

Seal architecture:

• Single O-ring face seal on main enclosure (Shore 70A silicone, UL-approved food-grade).
• Gore-Tex pressure-equalization vent (prevents thermal-cycling suction failure of O-ring — critical for -40 to +70 °C operation).
• Overmolded button + USB-C cover: Shore 60A TPE.
• Antenna pigtail: potted at entry point (2-part epoxy — Ambassador Tier-2 workstation).

Display + UI

• Lite / Trail: 0.96″ or 1.3″ OLED (128×64 or 128×128) for status, menu, message preview. ~$3.50 BOM.
• Expedition / Ultra: 1.54″ monochrome memory-LCD (Sharp LS013B7DH05, sunlight-readable, <50 µA operating) + 3 tactile buttons + rotary encoder. Mem-LCD is the Garmin inReach choice. ~$14 BOM.
• Ultra adds: second 1.0″ monochrome e-paper for persistent breadcrumb / status even when device is asleep (~$8 additional).

Buttons

• Lite: 2 tactile buttons (power / select) + SOS button under screw-retained cover (deliberate activation only).
• Trail + Expedition: 4 tactile buttons (up/down/select/back) + dedicated SOS button (red, recessed, cover) + check-in button (green).
• Ultra: 4 tactile + SOS + check-in + dedicated 2-way-messaging quick-reply button + rotary encoder for message composition.

All SOS buttons: 3-second hold + haptic confirmation + 10-second cancel window to avoid false triggers.

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Stage 2b — Configurator axes (2026-04-24)

10 axes per tier. See CONFIGURATOR.md for full matrix.

Stage 3 — Compatibility (2026-04-24)

Resolved:

• LoRa 915/868 MHz + BLE 2.4 GHz + Iridium 1616-1626 MHz L-band + Astrocast UHF 400 MHz + GNSS L1 1575 MHz + optional cellular LTE bands — all separate frequency bands. Antenna isolation is the issue, not frequency coexistence. Single-antenna shared-path is NOT possible; 4 separate antennas needed on Ultra (LoRa + BLE + Iridium + GNSS), 5 if cellular added.
• Nordic nRF52840 + SX1262 + SAM-M10Q GNSS: shared SPI bus with per-peripheral CS. Verified in Meshtastic T-Beam reference.
• BQ25798 MPPT + 18650 cell + solar panel: I²C config + programmable charge curve.
• Power budget: LoRa TX 120 mA @ +22 dBm; Iridium 9603N TX 1.5 A @ 5 V peak (burst 8.3 s); Astrocast TX 400 mA. Peak-current design for Iridium dictates minimum battery C-rate — 18650 with ≥2 C continuous rating is required (Samsung 30Q / Sony VTC6 class, NOT low-C-rate 3500+ mAh cells).

Deferred to Stage 5 (PCB layout):

• Antenna placement + ground-plane isolation for 4-antenna Ultra layout.
• Iridium modem SIM-card retention (emergency devices must not lose SIM under MIL-STD-810G vibration — spring-retained nano-SIM socket specified).

Stage 4 — Sourcing (2026-04-24)

Framework complete. See SOURCING.csv. Live RFQs deferred until Iridium + Astrocast partner terms commit.

Second-sources documented per preferred part. Long-lead flag on Iridium 9670 (>20 weeks per Ground Control 2026 quotes).

Stage 5 — DFM/DFA/DFT (2026-04-24)

See DFM-DFA-DFT.md. Critical: IP68 seal integrity is Ambassador Tier-2 — new potting + gasket-press + helium-leak-test workstation required. Adds 12-18 min/unit Ambassador time vs Bridge Mini baseline.

Stage 6 — Thermal / EMC (2026-04-24)

See THERMAL-EMC.md. -40 °C operating requires Gore-Tex pressure vent + cold-capable Li-ion + firmware temp-aware charge gate. +70 °C requires thermal path from Iridium modem (highest dissipator) to chassis via graphite pad.

Stage 7 — Compliance (2026-04-24)

See COMPLIANCE.md. FCC Part 25 satellite service resale is a business license, not a product cert — flagged.

Stage 8 — Canonical BOM + GUIDE + STLs (2026-04-24)

Files produced. STL-OPEN-FILES/README.md documents CC BY-SA 4.0 release for every 3D-printable part.

Stage 9 — HW/FW (2026-04-24)

Zephyr RTOS on Nordic nRF52840. Firmware partitions: bootloader / primary / secondary (A/B OTA) / Meshtastic interop / storage.

Stage 10 — Gate (2026-04-24)

See GATE.md + SERVICE-FLOW.md. Stage-10 blockers: Iridium SBD contract + GEOS / IERCC rescue-dispatch contract + FCC Part 25 resale license + Astrocast commercial terms (Ultra only).

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Open decisions carried forward

1. Whether to ship a 406 MHz Cospas-Sarsat PLB module on Ultra as Lux option — currently PLANNED but not in v1.0 launch BOM. 2. Whether Beacon Lite keeps Meshtastic-compatible firmware as default or ships WanderVerse-native protocol with Meshtastic bridging. Current decision: default Meshtastic-compatible (open-protocol principle + existing community mesh in many wilderness areas). 3. Whether to offer a "family plan" on Iridium service (4 WanderAway units + 1 WanderStation uplink share a monthly pool of SBD messages). Owner: ops. 4. Survivor safe-passage protocol spec — out-of-scope for hardware BOM but referenced in GUIDE.md; living doc in WanderSafe research + WanderShield integration.

D-NN — Radio function-class adopts Semtech LR2021 (LoRa Gen 4) as primary

Date: 2026-04-25 Strategy: hybrid

What changes: Radio architecture migrates to Semtech LR2021 (LoRa Plus, multi-PHY single-chip with sub-GHz + 2.4 GHz + S-band NTN satellite). Replaces previous SX1262 + nRF52840 + CC2652R7 multi-chip approach. Throughput 40× (62.5 kbps → 2.6 Mbps via FLRC); single global SKU; -142 dBm sensitivity; multi-protocol stack covers LoRaWAN + Sidewalk + Meshtastic + Z-Wave + Wi-SUN + BLE + Thread/Zigbee.

Sole-source variance: Semtech is sole-source for LR2021. Per SOLE-SOURCE-VARIANCE-LR2021.md:

• This product is Tier-1 critical, retains hybrid alt-source path: Founding-tier ships SX1262 + nRF52840 (proven dual-source); Pro / Global SKU ships LR2021 (single-chip, satellite-capable).
• Two PCB layouts; cert burden 2× but justified by global-SKU consolidation downstream.

Rationale: Dual-source rule's intent is supply-chain resilience and pricing power, not vendor purity. Modern equivalent for radio function-class is protocol-fallback compatibility, which LR2021 provides natively across 8+ stacks. Semtech is effectively a standards body now (450M LoRa devices shipped, LoRa Alliance backing).

[rule: dual-source-variance] [rule: dual-source]

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**Note (Perplexity-validated 2026-04-25):** When this doc says LR2021 supports multi-PHY in one chip, the *hardware* is multi-PHY-capable, but full protocol stacks (LoRaWAN, Amazon Sidewalk, Meshtastic, Z-Wave, Wi-SUN, BLE, Thread/Zigbee) integrate via firmware layers, not all bundled native. We ship pre-built stacks for the active set per product. See `PERPLEXITY-VALIDATION-2026-04-25.md` in `_WANDERVERSE-LIBRARY/`.