WeighTech

Smart waste-tracking IoT system — ESP32 scale that streams events to a Thai/English web dashboard via MQTT.

🏆 2nd Runner-up (รองชนะเลิศอันดับที่ 2) · ฿2,000 prize BU ECO WEIGHT IOTS 2026 · Bangkok University × Sodexo Thailand × ZIPCODE

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What it does

A worker presses 1 of 4 buttons on a smart scale (General / Plastic / Paper / Glass), drops waste on the platform, hears a beep — and within a second the event appears on a web dashboard with weight, CO₂ estimate, employee name, and location.

The point: give Sodexo Thailand real-time visibility into waste streams across 140+ cafeterias so they can produce GRI 306-3 ESG reports automatically instead of compiling them by hand from paper logs.

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Gallery

Admin Dashboard — KPIs, throughput chart, composition donut, device network, live event feed. Filter by SIM (demo) or REAL (live ESP32) mode.	Live Demo Page — designed for the projector during presentation. Big weight readout, source-tag chips, audience-scannable QR.
Employee Dashboard — personal greeting, monthly contribution, leaderboard rank, day-grouped history. Login: employee ID + name.	Thai i18n + SIM/REAL toggle — every page switches TH/EN, every value filters by data source for audit clarity.
Device Network — 124-bin fleet status with fill bars and online/offline state.	Behind the scenes — ESP32 firmware in Arduino IDE with serial debugging. HX711 calibration tuning.

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Architecture

[ESP32 Scale]  --MQTT 1883-->  [HiveMQ Broker]  --WSS 8884-->  [Web Dashboard]
     |                                                                |
     HX711 load cell + OLED + 4 buttons + buzzer                      Vanilla JS, 10 pages
     ~700 lines C++ firmware                                          ~3,000 lines JS
     3D-printed enclosure                                             TH/EN i18n, role-based access

Why this stack:

• ESP32 vs Raspberry Pi: ฿100 vs ฿1,500, lower power, faster boot, built-in WiFi
• HiveMQ public broker: zero-config for the demo (production = private broker + device certs)
• No web framework: 200ms TTFB on Vercel, ~80KB total bundle
• localStorage state: no backend, so hosting cost = $0 for the demo tier

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Hardware

Component	Spec
MCU	ESP32 WROOM-32 (38-pin Dev Module)
Load cell amp	HX711 24-bit ADC
Load cell	5 kg straight-bar strain gauge
Display	OLED SH1106 1.3" I2C 128×64
Input	4× tactile buttons (INPUT_PULLUP)
Audio	Passive 5V buzzer
Enclosure	3D-printed PLA, 95×62×50mm (designed in OpenSCAD)
BOM total	~฿800 retail

Pin map and calibration value live in ESP32/WeighTech_ESP32/WeighTech_ESP32.ino.

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Web platform

10 pages, 3 user roles:

Page	Path	Role
Login	/	Public
Dashboard	/dashboard	Admin
Live Demo	/live	Admin (projector view)
My Stats	/my-stats	Employee
Devices	/devices	Admin
Live Feed	/feed	Admin/Employee
Reports	/reports	Admin (ESG PDF export)
Team	/employees	Admin (leaderboard)
Admin Console	/admin	Admin (user management)
MQTT Debug	/mqtt-test	Dev tool

Role hierarchy: Super Admin (1, immutable) > Admin (managed by Super) > Employee (managed by any Admin).

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Run locally

cd Website
python3 -m http.server 8765
# Then open http://localhost:8765

Or just visit the deployed version: https://weightech.vercel.app

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Demo credentials

Super Admin

Email:    founder@weightech.co.th
Password: weightech2026

Employee (12 pre-registered, expandable via Admin Console)

ID: EMP-2026-001  + first-name "นภัส"
ID: EMP-2026-002  + first-name "ปกรณ์"
... etc

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Repository layout

WeighTech/
├── ESP32/                       Firmware (production .ino + calibration)
├── 3D_Print/                    Enclosure — .stl + OpenSCAD source + renders
├── Website/                     10-page web app (deployed to Vercel)
├── docs/                        ARCHITECTURE · PITCH · DEMO
├── archive/                     Legacy ESP8266 v1 firmware (kept for history)
├── Dashboard/                   Original UX mockups (design history)
├── images/portfolio/            Curated photos used in docs
├── PORTFOLIO.md                 Full case study writeup
├── RESUME_BULLETS.md            Copy-paste resume bullets (TH + EN)
├── LICENSE                      MIT
└── README.md                    This file

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Performance

Real Lighthouse scores against the deployed production URL (run 2026-06-23 via Lighthouse 13.4.0):

Page	Performance	Accessibility	Best Practices	SEO
/live (presentation view)	89	88	100	90
/ (login)	69	88	100	90

Login scores lower because it loads MQTT.js + Chart.js + 3 font families before redirect — acceptable for a demo, would code-split for production.

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Credits

Built by WeighTech team (Bangkok University, School of Engineering) for the BU ECO WEIGHT IOTS 2026 competition, sponsored by Sodexo Thailand and ZIPCODE.

• Hardware design + firmware: team
• Web platform + design system + deployment: Athit Boonpinit (@Maradosx)

License: MIT

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📬 Contact

Athit Boonpinit — Bangkok University, School of Engineering

• GitHub: @Maradosx
• Email: athit.boonpinit@gmail.com

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Live Demo → · Case Study → · Build Log → · Architecture → · Pitch Script → · Demo Runbook → · Changelog → · Resume Bullets →