Hydrogen Tracer Gas Detector PCB Design

Hi, I am looking for an electronics/PCB engineer to design a complete working PCB for my portable hydrogen tracer gas detector used for plumbing leak detection.

The purpose of the device is to detect hydrogen/forming gas (typically 5% H₂ / 95% N₂) escaping from underground or concealed water pipes.

Main functions required

1. Hydrogen gas sensor interface
• Designed around a suitable high-sensitivity H₂ sensor.
• I want good stability, fast response and the lowest practical PPM detection range.
• Sensor should preferably be replaceable/modular.
2. Active air sampling
• Small vacuum/sample pump draws air from a long probe into the sensor chamber.
• PCB should control/power the pump.
• Provision for suitable pump driver/protection circuitry.
3. Microcontroller
• Suitable MCU such as ESP32, STM32 or another recommended controller.
• Engineer can recommend the best option based on reliability, simplicity and cost.
4. Display
• Small LCD/OLED/TFT display.
• Display should show hydrogen concentration/signal level.
• Preferably show PPM if the selected sensor supports reliable PPM measurement.
• Battery level/status should also be displayed.
5. Audible leak indication
• Buzzer/beeper.
• Beeping frequency should increase as detected gas concentration increases.
6. Visual indication
• LED indicators and/or graphical sensitivity bar on the display.
• Increasing gas level should be easily visible to the operator.
7. Controls
• Power ON/OFF.
• Zero/calibration function.
• Sensitivity adjustment if required.
• Simple controls suitable for field use.
8. Power system
• Rechargeable lithium battery.
• USB-C charging preferred.
• Battery charging/protection circuit.
• Voltage regulation for the MCU, sensor, display and pump.
• Low-battery protection/indication.
9. PCB requirements
• Compact PCB suitable for a handheld detector.
• Proper grounding, filtering and power-supply design because sensor readings must be stable.
• Connectors for:
• Hydrogen sensor
• Pump
• Display if separate
• Battery
• Buzzer
• Buttons/switches
• Any external probe/sensor connection required

What I need from the engineer

The project must be delivered as a complete manufacturing-ready PCB design, not only a schematic.

Final delivery must include:

• Complete schematic
• PCB layout
• Gerber files
• BOM – Bill of Materials
• CPL / Pick-and-Place file
• JLCPCB-compatible manufacturing files if possible
• PCB fabrication files
• Assembly drawings
• Component reference/designator information
• Complete editable/source design files
• Firmware/source code for the microcontroller
• Programming instructions
• Wiring/connection diagram
• Basic testing procedure
• Calibration procedure for the hydrogen sensor

I want to be able to upload the Gerber + BOM + CPL directly to JLCPCB for PCB manufacturing/assembly.

Please do not use obsolete or extremely difficult-to-purchase components. Components should preferably be available from JLCPCB/LCSC, Mouser, DigiKey, RS, Element14 or other common suppliers.

Important

This is currently a working prototype / R&D project, so my priority is:

Stable readings → fast gas response → reliable field operation → simple design → easy manufacturing → easy servicing.

I do not need unnecessary complicated features at this stage.

Before starting the PCB layout, I would like you to provide:

1. Proposed block diagram
2. Recommended hydrogen sensor
3. Recommended MCU
4. Recommended sample pump
5. Proposed power architecture
6. Estimated PCB size
7. Main components you plan to use