Case Study / Augmented Reality & IoT

S-NODE AR App

An internship project at Dotcom IoT LLP that combines Unity, Vuforia, and C# to turn an Android tablet into a predictive-maintenance companion for S-NODE sensors. Scan a QR code, identify the device, and overlay live sensor data in augmented reality.

  • Unity 3D 2021.3.19f1
  • Vuforia 10.13.3
  • C# Scripting
  • MS SQL Database
  • QR / Barcode Scanning
  • Industry 4.0
  • Predictive Maintenance
Organization
Dotcom IoT LLP
Platform
Android Tablet
AR Engine
Vuforia
UI Scenes
11
S-NODE sensor device with AR QR overlay and Show Data button
S-NODE device scanned in Vuforia; the QR code triggers the AR overlay and the "Show Data" button queries the MS SQL backend.

00 / Demo

S-NODE AR in action

Screen recording of the Unity + Vuforia app scanning an S-NODE device and overlaying live sensor data.

Demo footage from the internship demonstration at Dotcom IoT LLP.

01 / Architecture

S-NODE ecosystem

The project sits on the full S-NODE IoT stack: wireless sensors, a gateway, cloud storage, and the AR tablet as the maintenance front-end.

S-NODE ecosystem diagram showing sensors, gateway, and dashboard
S-Node → Gateway → Dashboard — the same data pipeline the AR app taps into.
Project flow diagram for the S-NODE AR application
End-to-end application flow from QR scan to live AR overlay.

02 / Pipeline

From scan to overlay

Four stages turn a QR code on a sensor into a live, world-space diagnostics panel.

  1. 01 — QR scan

    Vuforia’s BarcodeBehaviour reads the QR code printed on the S-NODE device and stores the decoded UID for the current session.

    BarcodeBehaviour · TextMeshPro · UID capture

  2. 02 — Device lookup

    The C# backend opens a connection to the MS SQL database and queries the device record matching the scanned UID.

    SqlConnection · SqlCommand · SELECT TOP 1

  3. 03 — Scene switch

    Based on the device type returned by the database, SceneSwitcher.cs loads the matching UI scene (Environment, Vibration, Thermal, etc.).

    SceneManager.LoadScene · 11 device-type UIs

  4. 04 — AR data overlay

    The selected scene renders world-space UI panels anchored to the device, polling the SQL table for the latest sensor readings.

    World-space Canvas · Data refresh loop · AR camera

03 / Code Flow

How the app decides what to show

Vuforia handles recognition, C# handles decision-making, and the Unity scene manager swaps the UI for the detected sensor type.

Barcode scanner code flowchart
BarcodeBehaviour captures the QR code and passes the UID to the backend.
Scene switcher code flowchart
SceneSwitcher.cs maps the device type from SQL to the correct Unity scene.

04 / Features

What the app does

Built for maintenance technicians who need asset-specific data without leaving the equipment.

QR-driven device pairing

No manual serial entry — point the tablet at the device label, scan the QR code, and the app resolves the UID to the database record.

Type-aware UI scenes

Eleven distinct UI prefabs cover Environment, Vibration, Thermal, and other S-NODE sensor variants, each tuned to the data it displays.

Live SQL data binding

C# scripts query MS SQL on demand and refresh the AR panels, giving technicians current readings without leaving the equipment.

World-space telemetry cards

Sensor values float next to the physical hardware in world space, so the operator’s eyes stay on the asset while reading diagnostics.

One-handed tablet workflow

Designed for shop-floor use: scan, tap Show Data, and read — no laptop, no paper log, no separate HMI terminal.

Predictive-maintenance ready

By surfacing temperature, humidity, pressure, and vibration in context, the app supports early fault detection and condition-based servicing.

05 / Stack

Technology stack

A single Unity project, one Vuforia target pipeline, and a C# / SQL backend to drive the content.

ComponentRoleNotes
Unity 3D 2021.3.19f1AR interface & scenesVuforia integration, world-space UI, scene management
Vuforia 10.13.3Object & QR recognitionBarcodeBehaviour for device QR code scanning
C# .NETBackend logicSQL queries, scene switching, UI state management
MS SQL ServerSensor data storeDevice registry, live telemetry tables
TextMeshProAR typographyCrisp, scalable labels in the camera view
Android tabletDeployment targetPortable shop-floor maintenance companion

06 / Output Gallery

Live AR overlays

Scanning the device brings up the matching sensor UI; tapping Show Data refreshes the live reading from the MS SQL backend.

Vibration diagnostics scan overlay
Vibration diagnostics — scan overlay before data is requested.
Vibration diagnostics live data overlay
Vibration diagnostics — live data overlay after refresh.

Vibration diagnostics

The vibration scene shows peak acceleration values across the three axes (MAX, MAY, MAZ). In the captured run the device reported MAX −44.00, MAY 1973.00, and MAZ 97.00.

07 / Takeaways

Key learnings

What the internship proved about shipping AR on the factory floor.

  • AR closes the loop between asset and data

    By anchoring sensor readings to the physical device, the app removes the context-switching between a paper tag, a handheld meter, and a desktop dashboard.

  • QR codes make pairing invisible

    Scanning the device label turned a multi-step lookup into a single camera gesture, reducing the chance of querying the wrong asset on a busy floor.

  • Scene-per-sensor keeps the UI simple

    Dedicating one Unity scene to each sensor type meant each screen could show exactly the channels that matter, instead of a generic, cluttered layout.

  • Database latency matters in AR

    Polling MS SQL from a tablet over the shop network required careful query scope and UI debouncing; the overlay must feel instant even when the network does not.

  • Maintenance tools must be shop-floor tough

    A one-handed tablet workflow, large readable values, and high-contrast panels made the app usable while wearing gloves and standing next to running equipment.