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Sourcing Feasibility Report

Objective: PCB specification §7.1 only.
Checked: 2026-08-13.
Pricing basis: USD unit price at the smallest displayed LCSC tier suitable for a five-board build; prices and inventory are snapshots and must be rechecked when the BOM is locked.
JLC class note: Public LCSC product pages do not consistently expose JLCPCB's Basic/Extended designation. Commodity passives below are identified as Basic candidate; all special-function ICs, modules, connectors, switches, microphones, and uncommon values should be budgeted as Extended until the JLC BOM tool confirms otherwise.

No schematic or PCB objects were created or modified.

Executive feasibility result

Owner approvals frozen after Objective 1

RGB LED: Worldsemi WS2812B-V6, LCSC C52917433, APPROVED and frozen. The 5050 package is accepted for use with a light pipe and its outdoor brightness is desirable. XL-1615 remains rejected; do not use the 2020 variant.
LoRa module: Ai-Thinker Ra-01H, LCSC C503593, APPROVED and frozen. Its 803–930 MHz coverage supports both intended bands. RFM95W-915S2 is fallback only.
Bare ICS-43434 passes the hard availability check:
A compliant 3.3 V WS2812-protocol LED exists and is stocked: Worldsemi WS2812B-V6, LCSC C52917433, datasheet VDD 3.3–5.3 V, 41,490 in stock, $0.1013 at 5+. Use of this 5050 package would require owner approval because §4.5's example points to the much smaller XL-1615 class.
Worldsemi WS2812B-2020-V6, LCSC C52917434, is also datasheet-rated 3.3–5.3 V, but was out of stock at check time ($0.091 at 5+ when available).
XINGLIGHT XL-1615RGBC-2812B, LCSC C5349954, is not compliant: its LCSC-listed supply is 4.5–5.5 V. The related XL-1615 datasheet is internally inconsistent and states a recommended/input range beginning at 3.5 V, so it cannot be treated as guaranteed at 3.3 V.
The frozen major ICs/modules are presently feasible: ESP32-S3-WROOM-1-N16R8, BQ24074RGTR, TPS63020DSJR, ICS-43434, and Ra-01H all have LCSC listings and current stock.

§4 sourcing matrix

Table

§	Function / specified item	Proposed exact MPN	LCSC	Stock / status	JLC class	Unit price	Feasibility / action
4.1	MCU module	ESP32-S3-WROOM-1-N16R8	C2913202	14,739	Extended	$5.1608 (1+)	Pass, exact frozen variant.
4.1	EN / reset pull-up, 10 kΩ	0603 1% 10 kΩ commodity	Select at BOM lock	Widely stocked	Basic candidate	typically < $0.002	Pass; exact vendor can be chosen without changing value/package intent.
4.1	EN capacitor, 1 µF	0603/0805 X7R ≥6.3 V	Select at BOM lock	Widely stocked	Basic candidate	typically $0.003–0.01	Pass.
4.1	RESET tactile	K2-1114SA-A4SW-06	C136662	Listed	Extended	recheck	Pass candidate; SMD 4.8 × 3.5 mm. Mechanical approval deferred to capture/layout.
4.1	BOOT tactile	K2-1114SA-A4SW-06	C136662	Listed	Extended	recheck	Same candidate as RESET.
4.1	Bulk decoupling, 10 µF	0805 X5R/X7R ≥6.3 V	Select at BOM lock	Widely stocked	Basic candidate	typically $0.01–0.03	Pass.
4.1	Local decoupling, 100 nF	0603 X7R ≥16 V	Select at BOM lock	Widely stocked	Basic candidate	typically < $0.003	Pass.
4.2	USB-C receptacle, USB2 UFP	TYPE-C-31-M-12	C165948	425,665	Extended	$0.1716 (5+)	Pass; common 16-pin SMD receptacle. Final mechanical choice remains frozen once captured.
4.2	CC pulldowns, 5.1 kΩ ×2	0603 1% 5.1 kΩ commodity	Select at BOM lock	Widely stocked	Basic candidate	typically < $0.002	Pass.
4.2	USB ESD array	USBLC6-2SC6 (ST)	C7519	28,370	Extended	$0.1832 (5+)	Pass, exact class named in spec.
4.3	Power-path charger	BQ24074RGTR	C54313	5,535	Extended	$2.0482 (1+)	Pass, exact class. NTC may be biased with fixed 10 kΩ when no cell NTC is used; final ISET/ILIM values belong to Objective 2 and are not selected here.
4.3	Battery connector	B2B-PH-SM4-TB(LF)(SN)	C160352	Listed	Extended	recheck	Pass SMD vertical JST-PH-2.0 candidate. Spec says JST may be hand-soldered; final orientation must be approved before capture.
4.3	Power slide switch	SS-12D00-G3	C22355741	Listed	Hand-solder / exclude PCBA	recheck	Pass as the named through-hole equivalent. No SMD substitution proposed.
4.3	3.3 V buck-boost	TPS63020DSJR	C15483	9,438	Extended	$0.9647 (1+)	Pass, ≥1 A class. Exact inductor/capacitor/feedback network must follow the selected fixed 3.3 V implementation in Objective 2.
4.3	Buck-boost inductor	1 µH shielded, TPS63020-current-rated	Select after datasheet calculation	Multiple candidates	Extended	typically $0.10–0.40	Feasible, but exact MPN cannot be responsibly frozen before Objective 2 current/ripple check. No circuitry change implied.
4.3	MIC_3V3 ferrite bead	0603 ferrite, current-rated, impedance TBD	Select after filter check	Widely stocked	Basic/Extended candidate	typically $0.01–0.05	Feasible; exact impedance/current rating is not specified in §4.
4.3/4.4	MIC_3V3 bulk, 10 µF	0805 X5R/X7R ≥6.3 V	Select at BOM lock	Widely stocked	Basic candidate	typically $0.01–0.03	Pass.
4.4	I2S MEMS microphone ×4	ICS-43434	C5656610	5,198	Extended	$3.8216 (1+), $3.3464 (10+)	Hard-check pass: bare LGA microphone is available. PCBA process note remains critical: bottom-side, final reflow, no wash.
4.4	Per-mic 100 nF ×4	0603 X7R ≥6.3 V	Select at BOM lock	Widely stocked	Basic candidate	typically < $0.003	Pass.
4.4	Per-mic 1 µF ×4	0603/0805 X7R ≥6.3 V	Select at BOM lock	Widely stocked	Basic candidate	typically $0.003–0.01	Pass.
4.4	Optional SCK/WS series, 33 Ω ×2	0603 1% 33 Ω	Select only if routing condition triggers	Widely stocked	Basic candidate	typically < $0.002	Feasible; DNI unless stubs exceed the spec threshold.
4.5	Active 3 V buzzer, TH	TMB12A03	C96222	Listed	Hand-solder / exclude PCBA	recheck	Candidate only; verify that the current listing is the active 3 V variant before purchase. Do not use passive PS1240 parts.
4.5	Buzzer NPN	MMBT2222ALT1G	C82460	Listed	Extended	recheck	Pass; onsemi 40 V / 600 mA SOT-23. BC817 would also satisfy the allowed class but is not proposed as a substitution.
4.5	Motor NPN	MMBT2222ALT1G	C82460	Listed	Extended	recheck	Pass, same driver candidate. Motor current must remain within device/thermal limits.
4.5	Base resistors, 1 kΩ ×2	0603 1% 1 kΩ	Select at BOM lock	Widely stocked	Basic candidate	typically < $0.002	Pass.
4.5	Flyback diodes ×2	1N4148W, SOD-123	Select at BOM lock	Widely stocked	Basic candidate	typically $0.005–0.02	Pass; exact vendor not electrically material.
4.5	Motor bulk, 470 µF	470 µF low-ESR aluminum electrolytic, voltage ≥6.3 V	Select after footprint/height check	Available, but mechanically constrained	Extended	typically $0.10–0.40	Feasible; exact MPN must be chosen against enclosure height and ripple-current needs.
4.5	Motor bypass, 100 nF	0603 X7R ≥16 V	Select at BOM lock	Widely stocked	Basic candidate	typically < $0.003	Pass.
4.5	Addressable RGB LED	WS2812B-V6	C52917433	41,490	Extended	$0.1013 (5+)	Electrical hard-check pass: VDD 3.3–5.3 V. Package is 5050; owner approval required before replacing the XL-1615-class example.
4.5	Smaller alternate RGB LED	WS2812B-2020-V6	C52917434	Out of stock	Extended	$0.091 (5+) when available	Electrically compliant at VDD 3.3–5.3 V, but unavailable today. Closest compliant size alternative; do not select without approval and stock recovery.
4.5	Rejected RGB listing	XL-1615RGBC-2812B	C5349954	377,140	Extended	$0.0631 (10+)	Fail: LCSC states VDD 4.5–5.5 V. Not compliant with the 3.3 V hard requirement.
4.5	LED series resistor	330 Ω, 0603 1%	Select at BOM lock	Widely stocked	Basic candidate	typically < $0.002	Pass.
4.5	LED local bulk, 100 µF	100 µF aluminum/polymer, voltage ≥6.3 V	Select after footprint/height check	Available	Extended	typically $0.05–0.25	Feasible; exact MPN is mechanical/ESR dependent.
4.5	Snooze SMD tactile	TS-1187A-B-A-B	C318884	Listed	Extended	recheck	Pass candidate; 5.1 × 5.1 mm SMD.
4.5	Optional debounce, 100 nF	0603 X7R ≥16 V	Select at BOM lock	Widely stocked	Basic candidate	typically < $0.003	Pass/DNI option.
4.6	E-paper 8-pin 2.54 mm header	Generic 1×8, 2.54 mm straight male header	Select for hand solder	Widely stocked	Hand-solder / exclude PCBA	typically $0.05–0.30	Pass; cable-order/silkscreen requirement is more important than vendor.
4.7	Frozen LoRa module	RFM95W-915S2	C6760738	Listed; live quantity not confirmed	Extended	recheck	LCSC listing exists, but stock certainty is weaker than the approved alternative. Band-specific suffix must match deployment choice.
4.7	Approved LoRa alternative	Ra-01H	C503593	1,605	Extended	recheck	Available approved fallback, 3.3 V SPI LoRa module. Per spec, ask before changing footprint/module.
4.7	Wire/spring antenna	External 868 or 915 MHz wire/spring element	No single frozen MPN	User/region supplied	Hand fit	varies	Feasible; band-specific physical element must be selected for the deployment band.
4.8	Test points	SMD copper test pads / no purchased component	N/A	N/A	N/A	$0	Implemented as PCB features, not BOM parts.
4.3	Protected 1S ~3000 mAh pouch cell	Purchased separately	Not on LCSC/JLC BOM	Excluded	Excluded	N/A	Correctly excluded from PCBA and university lab use.
4.5	ERM vibration motor	Enclosure-mounted flying-lead motor	Purchased separately	Excluded	Excluded	N/A	Board contains two solder pads only; no motor is placed by JLC.

Availability flags and closest compliant alternatives

RGB LED: The small XL-1615 addressable listing fails the 3.3 V requirement. The stocked compliant alternative is WS2812B-V6 / C52917433, but it is a larger 5050 package. The closer-size compliant WS2812B-2020-V6 / C52917434 is currently out of stock. Approval is required before either schematic choice.
RFM95W: LCSC lists RFM95W variants, but current quantity was not reliably exposed during this check. The specification's already-approved closest alternative, Ra-01H / C503593, has 1,605 in stock. Ask before changing module/footprint.
Mechanically dependent parts: 470 µF and 100 µF bulk capacitors, the 1 µH high-current inductor, ferrite bead, buzzer, header, and switch are available product classes, but their final exact MPNs require the frozen electrical/mechanical constraints to be applied in their respective objectives. This report does not authorize substitutions or schematic changes.

Go / no-go conclusion

Conditional GO for capture: The design is broadly JLC-assemblable and the bare ICS-43434 requirement is currently feasible. Capture should not begin until the owner approves one 3.3 V-rated RGB LED/package and confirms whether to retain an RFM95W suffix or invoke the already-approved Ra-01H fallback. All inventory and JLC Basic/Extended classifications should be refreshed in the JLC BOM tool immediately before the BOM is frozen.

Executive feasibility result
Owner approvals frozen after Objective 1
§4 sourcing matrix
Availability flags and closest compliant alternatives
Go / no-go conclusion

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