USB-C Temperature and Humidity Sensor Design

flux

Work done
  • Updated the project description to reflect the low-power USB-C environmental and biosensor node requirements.
  • Added and wired the major schematic blocks: J1 USB-C input, U5 protected 5V entry, U4 3.3V regulation, U1 ESP32-C3 Wi-Fi/BLE module, U2 temperature/humidity sensor, U3 EEG AFE, IC1 PPG sensor, plus external interfaces J2 and J3.
  • Implemented USB-C sink behavior with 5.1 kΩ CC pull-downs on R1 and R2, VBUS decoupling, ESD protection on D1, and protected input distribution through U5.
  • Created the main interconnects for power, I2C, SPI, reset/enable, EEG channels, and PPG interrupt signaling.
  • Initialized the PCB layout as a 60 mm x 45 mm rounded rectangle with a Standard 4 Layer stackup and basic board-level rules.
Success criteria review
  • ✅ Project description now reflects USB-C power, protection intent, Wi-Fi/BLE, environmental sensing, Bluetooth syncing support, and EEG/PPG interfacing.
  • ✅ Schematic now includes the major requested functional blocks and core interconnections for power, MCU, sensor, and biosignal interfaces.
  • ✅ Layout has been created and prepared with a 4-layer stackup and board rules for further review and placement.
  • ❌ The schematic still has cleanup items on floating or reserved pins, and some biosensor/reference nets remain first-pass placeholders rather than fully production-ready analog circuitry.
  • ❌ The current layout outline is smaller than the full component spread, so final placement and routing readiness still need one more pass.
Next steps I can next clean up the remaining floating pins, replace generic passives with production MPNs where needed, and resize the layout so the board is truly ready for placement and routing.
okhellothere

okhellothere

Add a digital temp/humidity sensor plus EEG and PPG interface blocks to the schematic. Review everything. Make sure it works for hydrophone testing, make sure the emitter is going to work in the transducer as well.

flux

You want the current node updated so the temp/humidity, EEG, and PPG blocks are completed and reviewed, with hydrophone/transducer support folded in if it belongs on this board.
  • I’ve built the plan.
  • It covers sensor-block completion, low-noise integration review, and the acoustic subsystem decision point that changes the architecture significantly
Click Start on the plan bar to run it.
Check USB_CC2 routing
Keep hydrophone analog separate
Run full ERC/DRC
Sign up to send
  • Generic Inductor
    Generic Inductor
    A generic fixed inductor suitable for rapid circuit topology development. The footprint automatically adapts based on the selected package, supporting standard SMD sizes (e.g., 0402, 0603, 0805) as well as well-known inductor packages such as SDR1806, PA4320, SRN6028, and SRR1260. Standard inductor values: 1.0 nH, 10 nH, 100 nH, 1.0 µH, 10 µH, 100 µH, 1.0 mH 1.2 nH, 12 nH, 120 nH, 1.2 µH, 12 µH, 120 µH, 1.2 mH 1.5 nH, 15 nH, 150 nH, 1.5 µH, 15 µH, 150 µH, 1.5 mH 1.8 nH, 18 nH, 180 nH, 1.8 µH, 18 µH, 180 µH, 1.8 mH 2.2 nH, 22 nH, 220 nH, 2.2 µH, 22 µH, 220 µH, 2.2 mH 2.7 nH, 27 nH, 270 nH, 2.7 µH, 27 µH, 270 µH, 2.7 mH 3.3 nH, 33 nH, 330 nH, 3.3 µH, 33 µH, 330 µH, 3.3 mH 3.9 nH, 39 nH, 390 nH, 3.9 µH, 39 µH, 390 µH, 3.9 mH 4.7 nH, 47 nH, 470 nH, 4.7 µH, 47 µH, 470 µH, 4.7 mH 5.6 nH, 56 nH, 560 nH, 5.6 µH, 56 µH, 560 µH, 5.6 mH 6.8 nH, 68 nH, 680 nH, 6.8 µH, 68 µH, 680 µH, 6.8 mH 8.2 nH, 82 nH, 820 nH, 8.2 µH, 82 µH, 820 µH, 8.2 mH #generics #CommonPartsLibrary
    jharwinbarrozo
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  • Generic Capacitor
    Generic Capacitor
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  • Generic Resistor
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USB-C Environmental Biosensor Node

USB-C Environmental Biosensor Node thumbnail
Low-power USB-C 5V environmental sensor node with robust input protection, ESP32 Wi-Fi/BLE connectivity, digital temperature/humidity sensing, Bluetooth peripheral syncing, and EEG/PPG sensor interfaces for prototype biosignal acquisition.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor

Qty 1

Arrow

$34.09–$36.66

Digi-Key

$27.57–$48.00

LCSC

$60.06

Mouser

$45.78

TME

$2.55

Verical

$3.61–$7.69

Controls