USB-C Temp/Humidity Sensor Design

M

meemoe-ezz-300

Make me a temperature and humidity sensor node with Wifi and Bluetooth, powered by USB-C (5V) for consumer use.
It should be a low-power environmental node with a digital T/RH sensor, ultra-low-power MCU with Wi-Fi + Bluetooth (dual-radio) — 2.4 GHz 802.11 b/g/n plus BLE 5.x powered by USB-C (5 V) — USB-C receptacle 5 V default; include reverse/OVP/UVLO/OCP protection and plan for 0.5–3 A sources.

flux

I’ll build the schematic for a USB‑C powered Wi‑Fi/BLE environmental sensor node: select the MCU/sensor/protection/regulator parts, calculate the power path sizing, wire the circuit with required passives, add project/firmware notes, then run review checks and fix issues.

flux

I selected an ESP32-C3 module, SHT40 sensor, USB-C receptacle, TPS2595-class eFuse, 3.3 V buck regulator, USB ESD, buttons, LED, and generic support passives. I’m checking the active-part datasheets now so the schematic values and wiring follow the recommended circuits.

flux

Done — I created the schematic for the USB‑C powered Wi‑Fi/BLE temperature/humidity sensor node, including protected 5 V input, 3.3 V buck regulation, ESP32‑C3 module, SHT40 I2C sensor, USB data ESD, boot/reset buttons, status LED, and required decoupling/pull resistors.
I also added project files for the power/design notes, firmware starter, and review results. The schematic/ERC checks are clean; remaining full-review errors are expected because the board is not placed/routed yet and generic passives still need production MPNs before manufacturing.
Next checkpoint: I’m ready to move from schematic to layout — size the board, place components with the ESP32 antenna at the edge, then route after placement approval. Want me to proceed with layout?
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Files

Schematic

Layout

Preview

Design Review Results — Schematic Phase
Reviewed at: 2026-05-15T03:30:49.440Z
Schematic/ERC Status
Targeted schematic/ERC checks for floating pins, single-pin nets, undriven nets, power pins, no-connect markers, missing footprints, parts availability, decoupling, and capacitor voltage ratings returned no ERROR or WARNING results.
Remaining Review Items
The full review still reports expected non-schematic items:
  1. Airwires: The schematic has logical nets but the PCB has not been placed or routed yet. These will be resolved after layout placement and routing.
  2. Overlapping copper: Components have not been placed on a sized board yet, so default generated footprint positions can overlap. This is a layout-stage issue.
  3. Manufacturer Part Number on generic passives: Generic resistors, capacitors, and the inductor need production MPNs before manufacturing export. This does not block schematic validation but must be resolved before fab/assembly.
Datasheet-Grounded Design Checks Completed
  • ESP32-C3-MINI-1-N4: 3.3 V supply connected; all GND pads connected; EN has 10 kΩ pull-up and 100 nF reset filter; GPIO9 boot strap has 10 kΩ pull-up and BOOT button to GND; USB D-/D+ wired to GPIO18/GPIO19.
  • AP63203WU-7: 5 V protected input to VIN; 3.9 uH inductor; 10 uF input cap; 2 x 22 uF output caps; 100 nF bootstrap cap from BST to SW; FB tied to 3V3 for fixed output feedback.
  • SHT40: 3.3 V supply; GND/EP to GND; 100 nF local decoupling; I2C SDA/SCL connected with one shared 4.7 kΩ pull-up pair.
  • USB-C: CC1/CC2 each have independent 5.1 kΩ pull-downs; VBUS pins connected into the protected power path; D+/D- have low-capacitance ESD protection.
  • TPS259530 eFuse: VBUS input, protected output, dVdt capacitor, current-limit resistor, and fault flag pull-up/input are wired.
Before Manufacturing
Before export, complete these next steps:
  1. Size the board and place components.
  2. Put ESP32-C3 antenna at board edge with RF keepout.
  3. Place USB-C at board edge.
  4. Keep SHT40 away from regulator/USB heat sources.
  5. Place buck/eFuse passives close to their IC pins.
  6. Route traces and re-run full DRC.
  7. Assign production MPNs to generic passives or replace them with sourced passives.

  • Schematic/ERC Status

  • Remaining Review Items

  • Datasheet-Grounded Design Checks Completed

  • Before Manufacturing