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Connected hardware and controls

Industrial monitoring and control

A field-ready development system for environmental monitoring and equipment control in industrial composting.

Three sensing nodes, one gateway, and the engineering needed to connect them.

Stage reached
Field-ready development system
Sector
Industrial monitoring
Organisation
Independent engineering delivery

Explore the system

Loading 3D

Connected monitoring system with open enclosure, all sensor groups and electrical wiring

Connected sensor node

All six sensor groups connect to the enclosure, including three separate temperature probes.

My contribution

I designed and delivered the sensing and control system across component selection, electronics integration, embedded firmware, gateway software, mechanical packaging and physical assembly.

  • Mixed analog and digital sensor integration with persistent device configuration
  • C++ firmware, timed ventilation requests and MQTT communications
  • Raspberry Pi gateway, local buffering and application integration
  • Enclosure CAD, sensor harnesses, fabrication files and technical handover

The result

A built and shipped development system with sensor and event data checked with the receiving team, supported by the code, CAD and configuration material for continued field development.

Engagement

Prototype engineering and integrated delivery

The problem

The system had to bring gas, oxygen, moisture and temperature instruments together with local control outputs and a separate application. Different interfaces, sensor acquisition sequences, power connections and packaging all had to work together.

How it was approached

  1. Integrate I2C instruments, RS-485/Modbus probes and analog temperature channels into one acquisition application.
  2. Keep device acquisition and control separate from gateway coordination and application submission.
  3. Expose persistent settings and diagnostics for setup without source-code changes.
  4. Carry the physical assembly, wiring guidance and software into the same handover.

How far up the stack the work reached

  1. Process

    The composting environment and external equipment.

  2. Sensors

    Gas, oxygen, moisture, temperature and humidity instruments.

  3. Nodes

    Three ESP32-based units with acquisition, diagnostics and control interfaces.

  4. Gateway

    Raspberry Pi and Node-RED coordinating MQTT, time, files and requests.

  5. Application

    Data submission to the receiving application and a local development receiver.

Engineering disciplines

  • Mechanical
  • Electrical
  • Embedded
  • Software

What was built

Sensing and firmware

A common application for several kinds of instrument.

  • CO₂, ammonia, oxygen, moisture, ambient temperature and humidity
  • Three analog thermistor channels through an external ADC
  • RS-485/Modbus, I2C and scheduled acquisition
  • Persistent configuration, serial diagnostics and control-event messages

Gateway and network

A wired system with a clear application boundary.

  • Three sensor nodes and a gateway connected through an Ethernet switch
  • MQTT measurements, time broadcasts and ventilation requests
  • Sensor CSV buffering and retry workflows
  • Python Flask receiver, CSV interpretation and development database integration

Mechanical and physical delivery

Electronics packaged into an assembled development system.

  • Enclosure and baseplate CAD, assembly models and fabrication cutout drawings
  • Power, network, sensor and equipment connections
  • Sensor harnesses and gas-sampling hardware integration
  • Bench checks, setup documentation and source-file handover

What changed

3 sensor nodes

Distributed acquisition

Replicated sensing units acquired readings and communicated with the gateway.

1 gateway

Data and control integration

The Raspberry Pi gateway connected device messaging, file handling and the receiving software.

Physical delivery

Hardware and engineering files

The build was shipped with firmware, gateway workflows, mechanical files and configuration guidance.

Technical stack

ESP32

C++

Raspberry Pi

Node-RED

MQTT

Ethernet

RS-485 / Modbus

I2C

Python / Flask

CAD

Capabilities applied

Embedded systems

Sensor integration

Control interfaces

Mechanical packaging

System integration

2 frames

  • Complete monitoring node with black enclosure, corrected sensors, separate DIN harnesses and CO₂ sampling hardware

    System assembly

    Complete sensing system

    Connected instruments, separate sensor harnesses and the pump-controlled CO₂ sampling path. Cable bends and tube runs are reconstructed.

    Six sensor groups · Three temperature probes

  • Close view of the K30 flow director, clear sampling tubes, diaphragm pump and relay wiring

    System assembly

    CO₂ sampling and pump control

    The relay switches the sampling pump around CO₂ acquisition. Flow director, pump and tubing reconstructed from the documented hardware.

    Flow director · Sample tubing · Pump · Relay

Frame 1 of 2: Complete sensing system