PCB Design for Mach-Zehnder Interferometer

I need a PCB file created for a project that integrates a Mach-Zehnder Interferometer with multiple sensors.
# Project Title

**Custom Arduino Due–Based Multi-Sensor Data Acquisition PCB with Integrated LCD Display**

## Project Overview

I am looking for an experienced PCB/electronics designer to design a **custom standalone sensor device based on the Arduino Due platform**.

The objective is to have all required sensors and supporting electronics integrated onto a single custom PCB. Once the Arduino Due firmware is uploaded, the assembled PCB should function as a standalone device: the sensors should continuously acquire data, the Arduino Due should process the readings, and the measured values/statuses should be displayed on an **LCD permanently mounted on the PCB**.

I do not want the final product to depend on an external Arduino development board, breadboard, or loose jumper-wire connections during normal operation.

## Main Components / Sensors

The PCB needs to support the following sensors/modules:

* **BME680** – temperature, humidity, pressure and gas sensing
* **BMA400** – 3-axis accelerometer
* **VEML700** – UV sensor
* **HX711 – 2 modules/channels** – load-cell/weight measurement
* **KY-026** – flame sensor
* **KY-016** – RGB LED module
* **KY-006** – buzzer module
* **Arduino Due** – primary microcontroller
* **LCD display** – permanently mounted/integrated onto the PCB

The exact electrical implementation of the KY-series components should be reviewed during schematic design. Where practical, I would prefer the underlying components/sensors to be integrated directly onto the PCB rather than mounting complete hobby-module PCBs.

## Desired Function

The final PCB should operate as a complete embedded sensing device.

The intended operating sequence is:

**Power ON → Arduino Due starts → initializes all sensors → collects sensor data → processes data → displays readings/status on LCD → continuously updates measurements**

For example, the LCD could display pages such as:

**Environmental**

* Temperature
* Relative humidity
* Atmospheric pressure
* Gas/air-quality-related BME680 reading

**Motion**

* X-axis acceleration
* Y-axis acceleration
* Z-axis acceleration

**UV**

* UV sensor reading

**Weight / Load**

* Load Cell 1
* Load Cell 2

**Safety / Status**

* Flame detected / no flame
* Alarm status
* RGB LED status

The exact LCD interface and screen layout can be finalized during development.

## Arduino Due Integration

The Arduino Due should act as the central controller for the entire PCB.

I would like the PCB to be designed so that, after uploading the required Arduino program/firmware, the device operates independently without requiring a computer.

The designer should provide:

1. Complete schematic
2. PCB layout
3. Component footprints
4. Gerber files
5. BOM (Bill of Materials)
6. Pick-and-place/assembly files if applicable
7. Arduino Due integration/programming interface
8. Basic firmware/test code demonstrating that every sensor communicates correctly
9. Documentation showing the pin assignments and communication interfaces

The design should include an appropriate programming/debugging interface so that firmware can be uploaded or updated when required.

## Communication Interfaces

The designer should determine and document the appropriate interfaces for each component, including where applicable:

* I²C
* SPI
* UART
* Digital GPIO
* Analog inputs
* HX711 communication

The PCB should avoid unnecessary pin conflicts and should provide appropriate pull-up resistors, filtering, level compatibility, decoupling capacitors and other supporting circuitry required for reliable operation.

## Power Supply

The PCB should have a proper regulated power architecture suitable for the Arduino Due and all integrated sensors/peripherals.

The designer should calculate the expected current consumption and design appropriate:

* Voltage regulation
* Decoupling
* Power filtering
* Protection
* Grounding
* Power distribution

The required external power input can be discussed before final schematic approval.

## LCD Display

An LCD should be physically integrated into the PCB rather than being connected using loose wires during normal operation.

The display should be large enough to clearly show sensor readings and device status.

Ideally, the firmware should provide a simple interface such as multiple display pages/screens that can be switched automatically or using buttons.

The exact LCD technology, size, resolution and interface can be proposed by the designer based on the Arduino Due and the number of values that need to be displayed.

## PCB Requirements

The PCB should be designed as a professional, manufacturable board rather than a prototype breadboard-style circuit.

Requirements include:

* Proper component placement
* Clear silkscreen labels
* Ground planes where appropriate
* Proper power routing
* Decoupling near ICs/sensors
* Separation of sensitive analogue signals from noisy digital/power sections where appropriate
* Mounting holes
* Clearly labelled connectors
* Test points where useful
* Accessible programming/debugging connector
* Serviceability and reasonable component accessibility

The designer should also consider the physical placement of sensors carefully. Sensors that measure environmental parameters should not be placed in locations where heat from voltage regulators, the microcontroller, LCD backlight, or other components could significantly affect measurements.

## Important Design Consideration

I understand that some of the listed components are commonly available as inexpensive Arduino hobby modules. However, my objective is to create a **single integrated PCB/device**, not simply mount multiple existing breakout boards onto a larger PCB.

Therefore, during schematic development, please determine which components should be implemented directly at the IC/sensor level and which, if any, should remain as modules.

For example, the BME680 and BMA400 should preferably be implemented using their actual sensor ICs with the required supporting components and PCB footprints rather than requiring separate breakout boards.

For the KY-series devices, please verify the exact electrical circuitry and determine the most appropriate way to integrate their functionality into the custom PCB.

## Deliverables

The freelancer should provide:

### Hardware

* Complete electrical schematic
* PCB design/layout
* Final PCB design files
* Gerber files
* Drill files
* BOM with manufacturer part numbers where possible
* Component placement files if required for assembly
* PCB manufacturing/assembly documentation

### Firmware

A basic working Arduino Due program demonstrating:

* BME680 initialization and readings
* BMA400 initialization and readings
* VEML700 readings
* HX711 channel 1
* HX711 channel 2
* KY-026 flame detection
* KY-016 RGB LED control
* KY-006 buzzer control
* LCD initialization and display
* Basic error/status handling

The code should be structured so that I can later modify the displayed information and device functionality.

### Documentation

Please provide a clear document containing:

* Pin mapping
* Sensor communication interfaces
* Power requirements
* Sensor addresses where applicable
* Calibration procedure
* HX711/load-cell calibration procedure
* LCD connection/interface
* Programming procedure
* Assembly notes
* Basic troubleshooting information

## Testing Requirements

Before delivery, the design should be checked for:

* Electrical-rule violations
* Short circuits
* Incorrect power connections
* I/O conflicts
* Incorrect voltage levels
* Sensor communication problems
* Address conflicts
* Incorrect footprints
* PCB manufacturability

If possible, the freelancer should also provide a basic prototype/test procedure for verifying every sensor individually and then verifying the complete assembled device.

## Expected Final Result

The final result should be a **single custom PCB that behaves like a standalone multi-sensor instrument**.

I should be able to:

1. Power the device.
2. Upload the Arduino Due firmware.
3. Disconnect the computer.
4. Power the PCB independently.
5. Have all sensors operate automatically.
6. Have the Arduino Due collect and process their data.
7. View the sensor readings and device status directly on the integrated LCD.
8. Have the buzzer and RGB LED respond according to programmed conditions.

The design should therefore be approached as a complete **embedded electronic device**, rather than simply as an Arduino expansion/shield.

## Freelancer Requirements

Please have experience with:

* Arduino Due / ARM-based microcontrollers
* Custom PCB design
* KiCad, Altium Designer, Eagle, or equivalent
* I²C/SPI/UART sensor integration
* Analog signal conditioning
* HX711/load-cell circuits
* LCD interfaces
* Embedded firmware
* PCB manufacturing and assembly

Please include examples of previous custom PCB/embedded-system projects when submitting a proposal.

Before beginning the final PCB layout, I would also like to review and approve the block diagram and schematic so that any electrical/design issues can be resolved before PCB fabrication.

The following sensors and components need to be integrated:
- BME680
- BMA400
- VEML700
- HX711 (2 modules)
- KY-026
- KY-016
- KY-006
-LCD2004 soldered on board
Please propose whether an Arduino Due module or a bare SAM3X8E implementation is more appropriate, and explain the cost, complexity, programming method, and manufacturing implications before proceeding.

Ideal skills and experience:
- Experience with PCB design software (e.g., Altium, Eagle).
- Familiarity with integrating multiple sensors on a single PCB.
- Background in working with environmental and motion sensors.

Please provide samples of previous PCB designs.