Nozzle firmware
C++ firmware on the ESP32 that counts flow meter pulses, reads the dispenser signal, converts both to litres and latches a tamper alert the moment the nozzle sensor trips.
Fuel and energy case study: Every litre checked at the nozzle.
A fuel monitoring system that checks every fill at the nozzle, with ESP32 firmware, a Flutter app, a FastAPI backend and an admin panel for stations.
- Client
- Confidential
- Industry
- Fuel and energy
- Timeline
- 6 months
- Status
- Pilot
- Between live readings during a fill
- 1 s
- Parts built: firmware, app, backend and panel
- 4
- Photo evidence kept for review
- 90 days
- User roles, from super admin to driver
- 5
( The challenge )
What was getting in the way
When drivers, families and fleet owners fill up, they see one number: the reading on the pump. They have no way to check that the fuel that went into the tank matches it. A small shortfall on every fill adds up quickly, and without a record nobody can show where it happened.
Stations needed the same answer from the other side: a way to prove honest fills, find the dispensers and staff behind repeated problems, and act on it, all from one place.
( Our approach )
How we solved it
We put an independent measurement at the nozzle itself. An ESP32 device fitted there counts the fuel with its own flow meter and reads the dispenser's pulse signal at the same time, so every fill is measured twice and compared litre by litre.
The device runs its own WiFi hotspot, so the customer's phone connects to it directly and the check works at any pump, with or without mobile signal. The app shows the live readings every second, captures photo evidence and syncs each transaction to the backend, where configurable rules raise fraud alerts and escalate repeat cases automatically.
Stations manage everything from a web admin panel: a live view of every nozzle, fraud alerts, devices, transactions, reports and staff, with firmware updates sent to the devices over the air.
( What we built )
The pieces that make it work
Delivered in 6 months, with the source code, accounts and documentation handed over in full.
Live fill session app
A Flutter app that scans the pump's QR code, connects to the device's hotspot and shows both readings side by side every second until the fill is complete.
Offline first sync
Every transaction is saved on the phone first and synced the moment a connection returns, so a fill recorded without signal is never lost.
Fraud rules and escalation
A FastAPI backend that checks each fill against configurable discrepancy rules, raises fraud alerts and escalates staff and stations with repeated flags to a blacklist.
Station admin panel
A Next.js panel with a live nozzle monitor, fraud alerts, device management, transactions, reports, staff and complaints, with access set by role.
Remote device control
Devices are registered from the panel with their own key, receive commands remotely and install firmware updates over the air, reporting progress as they go.
( The outcome )
What changed for FuelSec.
- FuelSec is running as a pilot, with the device, app, backend and admin panel working together end to end.
- Every fill is measured twice at the nozzle and compared live, with any gap above 0.05 litres flagged.
- Tampering with the nozzle is reported the moment the sensor trips.
- Each transaction carries photo evidence, kept for 90 days for review.
- Fills recorded without mobile signal are saved on the phone and synced automatically.
- Repeat problems escalate on their own, flagging staff and stations for the owner to act on.
- Firmware updates reach every device over the air, straight from the admin panel.
- Between live readings during a fill
- 1 s
- Parts built: firmware, app, backend and panel
- 4
- Photo evidence kept for review
- 90 days
- User roles, from super admin to driver
- 5
( How it was delivered )
6 months, start to launch
- 1April
Live fill sessions
Sign in, the app and API foundations, and the live session between the phone and the nozzle device.
- 2May
Reports and admin
The admin panel modules for stations, with transaction history and reports.
- 3August
Production and fleets
Production deployment of the backend, and features for fleet owners managing vehicles and drivers.
- 4September
Fraud control and devices
Flagging and blacklisting rules, the remote command system for devices and over the air firmware updates.
( Services used )
- Mobile App DevelopmentCross platform apps, plus the backend and admin tooling that has to exist behind them.
- Web DevelopmentFrontend, backend and everything between, built from scratch rather than assembled from plugins.
- Systems IntegrationTwo way connections across payments, CRMs, messaging, calendars and databases.
- Cloud Deployment & InfrastructureCI and CD pipelines, edge hosting, monitoring and backups, on infrastructure you own.
( Built with )
- ESP32
- C++
- PlatformIO
- Flutter
- Dart
- FastAPI
- Python
- Firebase
- Firestore
- Cloudinary
- Next.js
- React
- TypeScript
- Railway
Mainstream tools with deep talent pools, so the client is never dependent on us to maintain what we built.
( Read next / Education )
PKR 1M+ in its first two months, on a platform built in two.
The founder reported PKR 1M+ in revenue in the first two months after launch, with no ad spend. The platform: an AI writing checker, speaking scores, Easypaisa plans and an admin panel, built in 2 months.
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