WiFi Water Flow Meter Design

flux

Complete: I created and wired the full schematic for the USB-C powered ESP32-S3 WiFi water flow meter, including 3.3 V buck regulation, 12 V boost sensor power, MAX3485 RS485 interface, USB-C protection/CC resistors, reset/boot circuitry, UART header, and status LEDs. Review returned no ERROR/WARNING/OPEN ERC issues.
I also created Design Notes with the architecture, power budget, assumptions, and pin map, plus Firmware Starter with PlatformIO/Arduino Modbus RS485 starter code. The main remaining assumption is the exact ultrasonic sensor’s Modbus register map; update the firmware once the sensor datasheet is chosen.
Schematic is ready for layout. Want me to proceed with board sizing and component placement?
ryanf

ryanf

Size the board and perform placement

flux

I’ll size the PCB first, set an appropriate stackup, then place components by functional block with the ESP32 antenna at an edge, USB and sensor connectors on board edges, and decoupling/power passives near their ICs. After placement I’ll run a DRC review and adjust if needed.

flux

Done. I resized the PCB to 100 × 80 mm with rounded corners and a 4-layer stackup, then placed all components by functional block.
Placement is clean: ESP32 is at the top edge with antenna overhang, USB-C is on the left edge, the sensor terminal is on the right edge, power stages are grouped, and user-facing LEDs/buttons/header are accessible. The only review errors now are expected unrouted connections because routing has not been performed yet.
Ready for routing when you are.
Yes route board
Set routing rules
Check antenna keepout
Review placement details
Add mounting holes
  • 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
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  • Generic Resistor
    Generic Resistor
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    20.5M
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    An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.
    natarius
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    RMCF0805JT47K0
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    CTL1206FYW1T
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ESP32 WiFi Water Flow Meter

ESP32 WiFi Water Flow Meter thumbnail
USB-C powered ESP32 WiFi water flow meter for a 3/4 inch PVC pipe using an external 12V RS485 ultrasonic flow sensor, protected power input, 3.3V logic, status LEDs, and programming/reset support.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor

Qty 1

Arrow

$6.78–$9.00

Digi-Key

$13.75–$15.54

HQonline

$1.39–$1.43

LCSC

$12.63–$12.73

Mouser

$20.76–$20.96

TME

$1.18–$1.31

Verical

$7.56–$10.20

Controls