Why this way.

WanderEnergy Family — Decision Log

Running log of decisions across Stages 0-10. Refined and extended from the local-LLM-drafted seed at /tmp/draft-wanderenergy-DECISIONS.md (validated 89/100, 2026-04-24). No Blueprint bundle progenitor, green-field spec informed by WanderVerse master plan + Sense + Emporia + Span + Shelly + IotaWatt competitive audit.

---

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

• Scope: whole-home + per-circuit electrical energy monitoring with disaggregation, on-device display, smart-home + utility-rate integration, identity-aware operation
• Competitive set: Sense Home Energy Monitor ($299, cloud-disaggregation, no per-circuit) · Emporia Vue 3 ($199, 16ch, cloud-required) · Span Smart Panel ($3,500+ install, 32-circuit replacement panel) · Shelly Pro 3EM ($179, 3-phase, no display, no NILM) · IotaWatt ($199, open-source, 14ch, no NILM) · Eyedro Home ($129, basic 2ch, cloud-required) · Aeotec Home Energy Meter Gen5 ($90, Z-Wave 3-clamp, no display) · Sense Solar ($349, +Sense+solar)
• Primary differentiators (unique):

1. On-device NILM disaggregation (TFLite-Micro on ESP32-S3): Sense ships disaggregation but it's cloud-only; we keep it local 2. Identity-aware "covert mode", no competitor addresses load-profile-as-surveillance against coercive housemates 3. CT clamps + voltage-reference-only for 2-channel and 8-channel (prices TBD), far below Span; Sense + Emporia require cloud account 4. Span Panel JSON-API parity, open API surface compatible with the existing Span ecosystem 5. Matter 1.4+ Energy Management cluster when ratified (forecast 2026); will be among first compliant

• Secondary differentiators: Ambassador-assembled · open-STL chassis · 7-year parts (with documented 5-year CT-recalibration cycle) · 60/30/10 Community Pool · CC-BY-SA STLs · DV-survivor advisory-vetted UX
• 6 LEADS / 8 MATCHES / 2 LAGS per _COMPETITIVE-AUDIT-2026-04-24.md
• 2 LAGS: (a) Sense's 4-yr trained cloud disaggregation model has a head-start on appliance-classification accuracy (we mitigate with public REDD + UK-DALE + WikiEnergy training corpus + Ambassador opt-in); (b) Span's full panel-replacement architecture supports per-circuit ON/OFF control which our CT-clamp design cannot (we explicitly do NOT pursue panel replacement, different product)

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

• Ideation source: WanderVerse master plan + cross-reference of Shelly Pro 3EM (form factor) × IotaWatt (multi-channel architecture) × Span Panel (API surface) × Sense (disaggregation feature)
• Decision: 2-tier family sized to the actual market gap:
• Standard (price TBD), 2 CT clamps (whole-house mains L1/L2), aims to replace Sense at a lower price + no cloud requirement
• Pro (price TBD), 8 CT clamps (per-circuit) + on-device NILM, replaces Sense + Emporia Vue + IotaWatt-with-NILM-add-on at competitive price with private disaggregation
• No tier 3: explicitly NOT pursuing a Span-style panel-replacement SKU. That's a different product class (electrical contractor sells it; UL Listed branch-circuit panel; $1,200+ install). WanderEnergy stays in the install-it-yourself-or-with-electrician CT-clamp class.
• Device IDs: WV-NRG-STD · WV-NRG-PRO
• Ship targets locked: Standard 2027-Q3 · Pro 2027-Q4
• Revision: v1.0-candidate

Stage 2: Component selection

MCU (both tiers):

• Espressif ESP32-S3-WROOM-1-N16R8: 16 MB flash + 8 MB PSRAM. Required for Pro NILM (TFLite-Micro model + per-circuit ring buffers); identical part across tiers for inventory simplicity. WiFi + BLE + 802.15.4 native: Matter-over-Thread + Matter-over-WiFi both supported.
• Backup MCU strategy: Nordic nRF52840 reference design preserved as dual-source contingency (no NILM on backup variant; whole-house only). Activated only if ESP32-S3 supply disruption > 12 weeks. Documented in SOURCING.csv.

Power management (both tiers):

• TI TPS65086100 PMIC: 6-rail integrated; mature; widely sourced via Digi-Key/Mouser; reused from medical_tricorder + router_pro_v2 family BOMs
• USB-C 5V input + optional 12VDC barrel jack for installations that prefer panel-side hardwire

Voltage sensing (both tiers):

• Voltage Reference Module VRM-001 (separate plug-in module, not in main unit), 120V North America (UL 1310 Class 2 isolated wall-wart that outputs scaled VAC reference signal to the main unit via 3.5 mm jack); 230V EU + 240V split-phase NA variants
• This isolates UL 61010 high-voltage handling to a small certified module rather than putting line-voltage on the main PCBA. Major DFM + safety win. Pattern borrowed from Shelly EM + IotaWatt.

Current sensing (varies by tier):

• Standard: 2× YHDC SCT-013-100 (100A primary, 50mA secondary, split-core, 2.5 mA/A) for whole-house L1+L2 mains
• Pro: 2× SCT-013-100 mains + 6× YHDC SCT-013-030 (30A primary, voltage-output, split-core) for branch circuits
• Burden resistor + DC offset bias network on PCBA per CT input
• ADC: TI ADS1115 16-bit Σ-Δ (4-channel × 2 chips for Pro = 8 inputs total; 1 chip for Standard = 4 inputs but only 2 used; 2 reserved for future voltage + temperature)

Display + UI (both tiers: identical):

• 1.3" monochrome OLED 128×64 SSD1306 I²C, saffron-tinted by physical filter overlay over white pixel emitter (display itself is monochrome white; saffron film between display + window achieves brand color)
• 3 tactile buttons (left/center/right) for menu navigation + display-mode toggle (kWh / sparkline / cost / circuit-detail-Pro-only)
• Status LED: single Cree CLM3C-AKA saffron LED (reused from family library) for offline/online + alert states

Connectors:

• USB-C (Amphenol 12401610E2) for power + serial console + firmware flash
• 3.5 mm TRS jack for VRM-001 voltage reference input
• 2× 3.5 mm TRS jacks for SCT-013 CT clamp inputs (Standard)
• DB15 expansion bay for 6× additional CT clamps + future expansion (Pro only)

Storage:

• ESP32-S3 internal 16 MB flash for OS + 6-month per-circuit ring buffer (Pro)
• Standard's 16 MB flash holds 18-month whole-house ring buffer at 1-second resolution

Protocol stack:

• WiFi 2.4 GHz (commissioning + telemetry to HA / app)
• BLE 5.0 (provisioning + Pro NILM training mode)
• Matter 1.4+ over WiFi (Energy Management cluster, once ratified; cert pursued at first SKU DVT)
• Local REST API (always-on, mDNS-discoverable; Span JSON-API surface parity for /api/v1/panel/... endpoints)

Power consumption:

• Standard: 0.6 W typical / 1.4 W peak (during full WiFi+OLED+ADS sampling)
• Pro: 1.1 W typical / 2.4 W peak (during NILM model inference + 8-channel ADS sampling)

Stage 3: Compatibility

• ESP32-S3 ↔ ADS1115 I²C (400 kHz): mature ESPHome driver; no contention with OLED on same bus (different addresses: ADS1115 0x48-0x4B, OLED 0x3C/0x3D, TPS65086 0x5E)
• CT-clamp signal conditioning: SCT-013-100 outputs 0-50 mA; burden resistor 33 Ω → ±0.83 V swing; bias network shifts to 0–3.3 V single-supply ADS1115-readable; anti-alias RC filter cutoff 1 kHz (well above 60 Hz fundamental + 20 harmonics)
• VRM-001 ↔ main unit (3.5 mm TRS): TRS carries 0-3.3 V scaled VAC reference; tip = signal, ring = bias-mid, sleeve = ground; cable shielded; max length 2 m
• OLED + 3-button + saffron LED: I²C OLED + GPIO buttons (3× with internal pull-ups) + RMT-driven LED, well-established stack, no resource contention
• Matter Energy Management cluster (1.4+): awaiting ratification; design accommodates by reserving cluster IDs in firmware schema; falls back to Matter 1.3 AirQuality-cluster-pattern temperature/total kWh report if cluster not ratified by ship date
• WiFi + BLE coexistence on ESP32-S3: Espressif coex driver standard; BLE used for commissioning only, then deactivated; no contention
• Span JSON-API parity: verified against Span's documented public API as of 2026-04. We mirror endpoints /api/v1/panel/circuits, /api/v1/panel/breaker, /api/v1/storage/*, returning matching JSON shapes where applicable (we lack the breaker-control fields, return 405 with helpful error)
• Mechanical fit: Standard 110×40×22 mm (Shelly Pro 3EM-style slim); Pro 130×55×28 mm with extension bay for DB15 + secondary CT inputs; both side-mount via 3M VHB + 2× M3 anchor screws to wall next to electrical panel (NOT inside the panel, line voltage isolation by design)

Stage 4: Sourcing

• YHDC SCT-013-030 / SCT-013-100: YHDC (Beijing Yaohua) direct via AliExpress + Mouser (Mouser stocks select SKUs); $5–8 per unit @ 1k; ⚠ single-source CN; 25% China tariff exposure; backup via Magnelab SCT-0750-100 (US, Boulder CO; $18/unit at 1k, 3× cost but no tariff) and AcuCT-H100-50A (Accuenergy CA; $14/unit @ 1k); dual-qualify both backups before EVT sign-off
• TI ADS1115: TI direct + Digi-Key + Mouser; $2.50–3.50 @ 1k; mature
• TI TPS65086100: TI direct + Digi-Key + Mouser; $3.20 @ 1k; mature; reused from family
• Cree CLM3C-AKA saffron LED: Cree/Wolfspeed direct + Digi-Key; $0.18 @ 1k; family-standard part
• SSD1306 OLED 1.3": various (Solomon Systech licensee); $3.20 @ 1k; commodity; CN tariff exposure
• ESP32-S3-WROOM-1-N16R8: Espressif direct + Mouser + Digi-Key; $4.20 @ 1k; mature
• Amphenol USB-C connector + 3.5 mm TRS jacks: Digi-Key + Mouser; $0.90 + $0.45 @ 1k; commodity
• Tactile buttons (3×): C&K + Alps; $0.30 each @ 1k
• VRM-001 (custom plug-in voltage reference module): custom design, UL-recognized wall-wart vendor (Mean Well or CUI) + scaled output transformer (Triad VPT24 series) + scaling op-amp (TI OPA325). $8.50 @ 1k landed including UL recognition transfer
• PCB 4-layer 105×35 (Standard) / 125×50 (Pro): JLCPCB + Sierra Circuits + PCBWay; $2.40 / $3.20 @ 1k
• Chassis (cream aluminum top deck + slate PETG sides + glass-fiber-reinforced PC bottom): Protolabs CNC top deck (anodized cream w/ saffron pinstripe paint mask) + Protolabs SLS slate sides; $7.20 / $9.40 @ 1k
• CT-clamp pigtails + 3.5 mm TRS terminations: Rean / Neutrik via Digi-Key; $0.85/cable @ 1k
• Packaging pulp + soy-ink: EcoEnclose; $2.40-3.20

See SOURCING.csv for full vendor matrix + tariff notes.

Stage 5: DFM / DFA / DFT

• Standard assembly: ~22 min Ambassador work per unit (PCBA from CM is pre-populated; Ambassador hand-installs OLED+saffron filter, glues CT-clamp pigtails to chassis, integrates VRM-001, calibrates, packages, signs). Tier 1 Ambassador, electrical understanding required for CT-clamp orientation testing.
• Pro assembly: ~32 min/unit (extra CT-clamp pigtails + DB15 expansion harness + NILM bootstrap firmware flash + extended self-test)
• Test coverage: 12 tests per Standard / 18 tests per Pro (boot, OLED draw, button press, ADS sampling on each CT input with reference current source, VRM signal verification, WiFi association, BLE commissioning, Matter announce, OTA flash, encrypted-storage write/read, NILM model load (Pro only), Span-API parity smoke test)
• DFT (Design for Test): every CT input gets a known-current-source jig (Ambassador's bench has a 50 W heater coil on a calibrated 5 A through-circuit; ±0.5% reference accuracy) for end-of-line CT-input characterization
• DFA fixtures: chassis-clamping fixture for OLED+filter alignment (saffron pinstripe + cream top deck must align ±0.3 mm); torque-controlled 0.6 N·m driver for M2.5 captive screws; static-safe ESD bench (per FCC + UL pre-cert hygiene)

Stage 6: Thermal / EMC

• Thermal: both tiers passive-cooled. Standard 0.6 W typical / 1.4 W peak; Pro 1.1 W typical / 2.4 W peak. Worst-case junction temp on ESP32-S3 ~ 65 °C at 35 °C ambient. PETG side walls handle 80 °C+. No thermal cliff in operating envelope (panel-side ambient up to 50 °C accommodated).
• EMC pre-cert challenges: CT-clamp pigtails act as antennas for both ingress (panel-radiated noise from inverter switching, breaker arcing) + egress (test-equipment broadcast). Mitigation:
• Common-mode chokes on each CT pigtail at PCBA entry (Murata BLM18 series)
• Shielded CT-clamp cable (Belden 9501 equivalent, twisted pair + foil shield)
• Star ground topology with single-point analog/digital ground tie at ADS1115
• Ferrite bead on USB-C power input
• Y-cap pi-filter on USB-C power input
• ESD Level 4 (IEC 61000-4-2) on USB-C + TRS jacks (TVS diodes inline: PRTR5V0U2X)
• FCC Part 15 B + C: inherited from pre-certified ESP32-S3 module; device-level FCC test ~$3-5k each tier
• CT-clamp safety: each CT clamp ships with explicit "do NOT clamp around line conductors with insulation removed" + "do NOT exceed 100A primary continuous" + "always close jaws fully — open clamps generate dangerous open-secondary voltages" warnings
• UL 61010-1 (electrical measurement equipment): the main cert. CT-clamp signal-conditioning section needs reinforced isolation per UL 61010 Annex K. Achieved by routing CT inputs through transformer-isolated burden resistors (no galvanic path from CT secondary to ESP32 ground).

Stage 7: Compliance

• UL 61010-1 (electrical measurement equipment): HARD GATE for both tiers; ~$22-30k per major variant; 16-20 wk lead time; Intertek Chicago primary
• UL 1310 Class 2 isolation for VRM-001 wall-wart (procured pre-certified from Mean Well; no in-house cert needed)
• FCC Part 15 B (Class B digital): ~$3-5k per SKU; 12 wk
• FCC Part 15 C (radio): inherited from ESP32-S3 module
• CE RED + UKCA + ISED + ACMA: ~$8-12k family; 12-14 wk
• CE EN 55014-1 (household appliance EMC), applicable due to permanent install; ~$4-6k family
• RoHS 3 + REACH + Prop 65: ~$1k family
• Energy Star Connected Energy Monitor: pursue recognition; ~$3-5k per SKU; 12 wk; consumer-facing label drives ~10-15% preference lift in retail
• CARB energy-claim alignment: California has no formal cert for energy monitors (it's not an air cleaner) but CARB does enforce truth-in-energy-claims under §94505. We file a self-certified compliance attestation + retain test data; ~$1-2k legal review
• Matter 1.4+ Energy Management cluster: pursued contingent on cluster ratification; CSA cert ~$15-25k family
• Total cert budget v1.0: ~$80-115k (UL 61010 dominates)

See COMPLIANCE.md for full matrix.

Stage 8: Canonical BOM + GUIDE + STLs

See BOM-platform.csv, BOM-modules.csv, BOM-normalized.csv, GUIDE.md, STL-OPEN-FILES/README.md.

Stage 9: HW ↔ FW binding

• Firmware: ESPHome 2026.5+ base + custom WanderOS-NRG overlay
• Rationale: ESPHome has mature ct_clamp + total_daily_energy + ads1115 components; we contribute upstream
• WanderOS-NRG overlay adds: Matter 1.4+ Energy Management cluster (when ratified), TFLite-Micro NILM inference (Pro), Span JSON-API endpoint shim, covert mode display logic, identity-aware preset router
• NILM model (Pro): TFLite-Micro INT8-quantized CNN+LSTM hybrid; trained on REDD + UK-DALE + WikiEnergy public corpus + opt-in Ambassador household data; 8 appliance classes at v1.0 (HVAC compressor, electric resistive heat, water heater, electric range/oven, refrigerator, EV charger, dishwasher, dryer); model size ~2.4 MB; inference ~180 ms on ESP32-S3 PSRAM
• OTA: ESPHome OTA via HTTPS from WanderNode Hub or user-configured update server
• Local API: mDNS-discoverable _wanderenergy._tcp.local; REST endpoints documented in HW-FW.md; Span Panel JSON-API parity shim at /api/v1/panel/...
• Development cost: ~$160k (1 FTE firmware, 0.5 FTE Matter integration, 0.5 FTE NILM training/optimization, 0.5 FTE app/HA integration, 0.25 FTE QA) across 9 months

Stage 10: Gate review

EVT/DVT/PVT stages per GATE.md. Ship-target summary:

• 2027-Q3: Standard first customer ship
• 2027-Q4: Pro first customer ship
• 2028-Q2: NILM v1.1 with 12 appliance classes (post-1-year field-data harvest)

---

Critical decisions this session

#	Decision	Impact
1	Two tiers (Std 2-CT $249 / Pro 8-CT $449), explicitly NOT pursuing a Span-style panel-replacement SKU	matches market gap without UL Listed branch-circuit panel cert burden
2	**VRM-001 plug-in voltage reference module** isolates UL 61010 high-voltage handling to a small pre-certified wall-wart module rather than putting line voltage on the main PCBA	reduces UL cert risk + cost on main unit; pattern from Shelly EM + IotaWatt
3	**TFLite-Micro on-device NILM** on Pro (Sense ships disaggregation cloud-only)	category-defining privacy posture: the energy monitor knows what's on without telling anyone
4	**Identity-aware "covert mode"** as Standard 6b + Standard 3 enforcement line, display defaults to total kWh only; per-circuit data in encrypted local storage	unique in the energy-monitor category; addresses real DV-survivor surveillance vector
5	**Span Panel JSON-API parity** at `/api/v1/panel/...` endpoints	day-one HA + openHAB + Home Assistant Energy Dashboard compatibility; positions us as Span-replacement at 1/15th the cost for households who don't need breaker control
6	**Matter 1.4+ Energy Management cluster** when ratified	first-mover positioning in the standardized smart-home energy category
7	**Tier 1 Ambassador only** for both SKUs, electrical experience required for CT-clamp orientation walkthrough	safety + Standard 1 (supported employment) honored with documented training requirement
8	**YHDC CT clamps + Magnelab + AcuCT triple-source qualification** before EVT sign-off	de-risks China-tariff exposure on consumable / 5-year recalibration cycle component
9	**5-year CT recalibration cycle as documented + serviceable** (not glossed): Ambassador send-back service @ $25 + parts	7-year parts commitment honored with documented exception (CT clamps drift over time; this is a known property of the technology, not a fault)
10	**CC-BY-SA STLs** for chassis, mount, repair-bit holder, expansion-bay cover	repair culture + Standard 4 alignment
11	**Saffron pinstripe + cream top deck + slate sides + 1.3" mono OLED + 3 tactile buttons** as visual signature aligned with reference image	distinctive industrial-minimalist (Shelly Pro 3EM × IotaWatt × Span), readable at 6 ft from a panel mount
12	**No Perplexity queries during this draft** per identity-aware-data hygiene + Tier-2 strategy data, competitive analysis from local cached competitor docs only	platform standard 3 enforcement
13	**HAVEN safehouse + DV-survivor preset** auto-enables covert mode + 30-day rolling log auto-wipe + no Apple Health / Google Health export prompt	Mission Partner alignment
14	**No NILM appliance class is gendered, race-coded, or sexuality-coded**, model trained on appliance categories only (HVAC / fridge / EV / etc.) never on user-class proxies	Standard 5 (no surveillance against marginalized groups)
15	**No cloud account ever required**: Standard mode 1 is full-featured standalone; cloud / app are opt-in additions	Standard 6 (local-first by default)