ESP32 Water Level Warning System
Worked for 3 mins 18 sec
I found one power issue: a second ESP32 should not share the existing AP2112K 3.3V regulator because two WiFi ESP32 modules can exceed its 600 mA rating. I’m correcting this by giving the receiver its own USB-C power/programming and 3.3V regulator block.
Worked for 7 mins 7 sec
Added the RX device to the ESP32 water-level system.
What changed:
- Added receiver ESP32-S3 node: U4.
- Added independent receiver USB-C power/programming: J2.
- Added receiver 3.3V regulator: U5, with input/output/bulk capacitors.
- Added receiver alarm outputs: BZ2 buzzer via Q2 transistor driver and LED2 status LED.
- Wired TX/RX architecture for wireless ESP-NOW/WiFi communication; no direct signal wire is needed between U1 and U4.
- Updated firmware file with TX and RX ESP-NOW example code.
- Updated project specification with the new Tx/Rx architecture and receiver power path.
Validation:
- ERC shows no open schematic errors/warnings.
- Remaining review issues are PCB airwires because layout/routing has not been done yet, plus generic passive MPN warnings for manufacturing.
Updated files:
- Project Specification
- Firmware Starter — ESP32-S3 Water Level Early Warning System with Tx/Rx Devices
Start PCB layout
Fix manufacturing warnings
Add test points
Check power budget
Optimize BOM cost
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Project Specification: ESP32 Water Level Early Warning System
Project Overview
Status: Draft. ESP32-based early warning node for monitoring water level and triggering local/WiFi alerts when water rises beyond configured thresholds.
Intended Use
Prototype field/deployment monitor for drains, tanks, rivers, or flood-prone points. The ultrasonic sensor is mounted above the water surface and measures distance to water.
What the Device Should Do
- Measure water distance/level periodically.
- Trigger warning through buzzer and status LED when threshold is crossed.
- Provide WiFi/BLE-capable ESP32 platform for sending alerts to a server/app.
- Support USB-C power and firmware programming.
Main Features
- ESP32-S3 WiFi/BLE MCU module.
- Second ESP32-S3 receiver/alarm device for remote warning output.
- Waterproof ultrasonic water-level sensor module.
- USB-C 5V input with 3.3V regulation.
- Receiver has its own USB-C 5V input and local 3.3V regulator so the two ESP32 devices do not overload one LDO.
- Local audible buzzer alarm and status LED.
- Boot/reset buttons for easy firmware flashing.
System Architecture
Diagram
Hardware Subsystems
- Power: TX USB-C 5V input and 3.3V LDO for U1; RX USB-C 5V input and separate 3.3V LDO for U4; 5V rail for ultrasonic sensor on the TX node.
- Compute/Communication: ESP32-S3 module with WiFi/BLE and native USB programming.
- Sensing: JSN-SR04T-style waterproof ultrasonic sensor module.
- Alert/UI: active buzzer plus status LED.
- Receiver: second ESP32-S3 with independent EN/BOOT support, decoupling, status LED, and buzzer driver for remote alerts.
- Protection/Support: USB-C CC resistors, USB ESD protection, reset/boot circuitry, decoupling.
Interfaces and Connections
- USB-C: VBUS, GND, D+, D-, CC1, CC2.
- Sensor: 5V, GND, TRIG, ECHO; ECHO is level-shifted to ESP32 3.3V input.
- ESP32 GPIO: trigger output, echo input, buzzer control, LED control, boot/reset.
- Wireless Tx/Rx link: U1 sends alert packets to U4 via ESP-NOW/WiFi; no direct wired signal connection is required.
- RX ESP32 GPIO: GPIO18 drives receiver buzzer transistor Q2, GPIO21 drives receiver status LED LED2, GPIO0/EN provide boot/reset.
Power and Runtime Expectations
Prototype assumes USB-C 5V power. Battery/solar operation is not included yet and can be added later.
Power Tree and Power Budget
Estimated per-node peak loads: each ESP32-S3 can require about 500mA peak on 3.3V, plus roughly 30mA buzzer and 2-5mA LED. TX and RX now use separate AP2112K 600mA regulators; each regulator is marginal but acceptable for prototype peak current. Thermal dissipation should be checked in layout and firmware should avoid sustained maximum WiFi TX plus buzzer load.
Manufacturing and Assembly Expectations
Default to SMD components for a compact prototype PCB. Add test points and mounting holes during layout if requested.
Firmware-Relevant Hardware Requirements
Arduino/ESP-IDF firmware should configure ultrasonic trigger/echo timing, thresholds, buzzer PWM/GPIO, LED status, WiFi connection, and remote alert publishing.
Physical Design Expectations
ESP32 antenna must be at the PCB edge with keepout. Sensor connector should be board-edge accessible. USB-C should be at board edge.
Important Design Decisions
- ESP32-S3 chosen for WiFi/BLE and native USB programming.
- Waterproof ultrasonic module chosen for non-contact level measurement.
- USB-C powered prototype chosen because the user did not specify battery/solar.
- Sensor ECHO line is level-shifted from 5V to 3.3V for ESP32 safety.
Assumptions
- Monitoring range fits the JSN-SR04T-style 20-600 cm ultrasonic sensor.
- USB-C 5V power is acceptable for the first prototype.
- Local buzzer and LED are sufficient for local warning; network alert behavior will be firmware-defined.
Change Notes
- Initial specification created from the user request on 2026-06-02.
- Added independent receiver USB-C power/programming and receiver 3.3V regulator on 2026-06-02.
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