Temperature and Humidity Sensor Node Design

flux

I continued until ACUs became unavailable. Completed: renamed/described the project, selected the architecture and parts, built the schematic with USB‑C input, TPS2595 eFuse protection, MP28301 3.3 V buck, ESP32‑C3 Wi‑Fi/BLE module, SHT41 sensor, USB data ESD, boot/reset, status LED, and created project files for the spec, power budget, firmware starter, bring-up plan, and regulatory notes.
Remaining work:
  • Re-run ERC after the last cleanup step and resolve any remaining warnings.
  • Confirm no-connect markings were applied for unused ESP32/J1 pins.
  • Perform PCB placement/routing, especially ESP32 antenna keepout, buck layout, USB routing, and sensor thermal isolation.
  • Run DRC/airwire checks after layout.
  • Validate final TPS2595/MP28301 settings against datasheets before manufacturing.
A

angierg27

continue

flux

I’ll inspect the current schematic and project docs, run design checks, then fix any schematic issues I find before summarizing what remains for layout.

flux

I’m blocked because the account has no available ACUs, so I can’t continue AI layout actions right now.
Completed this session:
  • Verified the schematic/ERC state: no open errors or warnings were reported.
  • Set up the PCB as a 45 mm × 30 mm rounded rectangle with a standard 4-layer stackup and 0.5 mm board keepout.
  • Confirmed the board area is workable, though routing may be tight around the ESP32/power section.
Remaining work:
  • Place components with ESP32 antenna keepout, USB-C edge placement, compact buck/eFuse layout, and isolated SHT41 placement.
  • Route the PCB.
  • Run DRC and airwire checks.
  • Fix any routing or layout violations before manufacturing export.
Review placement constraints
Check ACU balance
Run layout checks
Estimate board size
Sign up to send

Files

Schematic

Layout

3D View

Board Bring-Up Plan
Pre-Power Checks
  1. Inspect USB-C connector, eFuse, buck regulator, and ESP32 module soldering.
  2. Check resistance from VBUS_RAW to GND and 3V3 to GND; confirm no hard short.
  3. Confirm CC1 and CC2 each measure about 5.1 kΩ to GND.
First Power
  1. Power from a current-limited 5 V bench supply or USB current meter.
  2. Verify VBUS_RAW at J1 and VBUS_PROT at U3 OUT.
  3. Verify 3V3 rail at U1 3V3 and U2 VDD.
  4. Confirm eFuse does not current-limit during idle boot.
Programming
  1. Connect USB-C to a development machine.
  2. Hold BOOT, tap RESET, release BOOT if manual download mode is needed.
  3. Flash the firmware starter using PlatformIO.
  4. Confirm serial console over native USB.
Functional Tests
  1. Read SHT41 over I2C and verify plausible T/RH values.
  2. Verify Wi-Fi association and reconnect behavior.
  3. Verify BLE provisioning behavior when implemented.
  4. Confirm status LED current and firmware duty cycle.
Power/Signal Validation
  1. Scope 3V3 during Wi-Fi transmit; verify no brownout dips.
  2. Check buck switch node for excessive ringing.
  3. Check USB D+/D− enumeration reliability.
  4. Validate sensor thermal offset with enclosure installed.
Pass Criteria
  • 3V3 remains within regulator tolerance under Wi-Fi bursts.
  • USB enumeration and firmware upload are reliable.
  • Sensor readings are stable and not heat-biased by board placement.
  • No abnormal heating in U3/U4/L1 during continuous Wi-Fi operation.

  • Pre-Power Checks

  • First Power

  • Programming

  • Functional Tests

  • Power/Signal Validation

  • Pass Criteria