Pcb Design - Monitoring Device with Esp32 and Advanced Sensor Integration

We are seeking an experienced electronics engineer or PCB designer to develop a manufacturable Printed Circuit Board (PCB) for a hydroponic monitoring device. The design must be robust, reliable, and suitable for both prototyping and long-term field operation in humid environments. Attention to detail in component selection, layout, and protection mechanisms is crucial.

Key requirements include:

Microcontroller:
- Integration of an ESP32-WROOM-32 module, leveraging its integrated Wi-Fi and Bluetooth capabilities.

Power Supply:
- 12v dc input via a pcb-mounted dc jack connector (5.5 × 2.1 mm).
- Implementation of reverse polarity protection.
- Overvoltage protection circuit.
- A buck converter to efficiently step down 12V to 5V.
- A Low-Dropout (LDO) regulator to convert 5V to 3.3V for sensitive components.
- Proper selection and placement of bulk and decoupling capacitors for stable power delivery.

Sensor Connections (MANDATORY):
- Each sensor must connect using a panel-mount, waterproof M12 female connector (A-coded).
- M12 connectors must be strategically placed on the PCB edge for easy enclosure integration.
- Each M12 connector must expose vcc, gnd, and signal / data pins as required by the specific sensor.

Sensors to be integrated:
- pH sensor: Requires an analog input (0–3v) with a dedicated rc low-pass filter and a tvs diode for esd protection.
- EC sensor: Requires an analog input with a dedicated rc low-pass filter and a tvs diode for esd protection.
- Water temperature sensor: DS18B20 (1-Wire) with a 4.7kΩ pull-up resistor.
- Air temperature and humidity sensor: DHT22 (digital interface).
- Light sensor: BH1750 (I²C interface).

USB Interface:
- A USB connector must be included for programming the ESP32 and for debugging purposes.

Protection and Layout Rules:
- Strict separation of analog and digital ground planes.
- Implementation of a single-point (star) ground connection to minimize noise.
- Analog sensor traces must be kept physically separated and away from the ESP32 Wi-Fi antenna to prevent interference.
- No copper or signal traces are allowed under the ESP32 antenna keep-out area.
- Comprehensive ESD protection must be applied to all external connectors.

Additional Features:
- Status LEDs for Power, Wi-Fi activity, and Error indication.
- A reset push button, designed to be easily accessible from the final enclosure.
- An internal uart debug connector (tx, rx, gnd) for development and troubleshooting.
- Mounting holes for secure installation within an IP65 waterproof enclosure.

Deliverables:
- Complete, professional schematic diagram.
- Detailed real component selection, including part numbers and datasheets.
- Comprehensive PCB layout proposal, ready for manufacturing.
- A Bill of Materials (BOM).
- Clear ESP32-WROOM-32 pin assignment documentation.

We are looking for a freelancer with a strong background in embedded hardware design, power management, sensor integration, and robust PCB layout practices for challenging environments.