ATEX Tanker Trailer Monitoring System IoT System Build (Hardware/APIs)

We are building a fuel tanker trailer monitoring system (pilot project) for petrol-PMS/diesel (AGO) distribution clients in our region. We have a detailed technical blueprint and now need:
1. Organizations/suppliers who can provide industry‑rated, ATEX‑compliant hardware (fuel level probes, smart GPS locks, telematics gateways, etc.) at prototype‑friendly pricing, ideally with OEM/white‑label options.
2. Embedded/firmware engineers and backend/API developers to integrate this hardware with our web/mobile platform via Modbus RS485, MQTT, and REST APIs.

Note: This is a pilot project phase with ability to scale the concept to a wider client base after the tests.

What We Already Have
Complete system architecture and hardware list but need to know if we can get manufacturers with industry rated capabilities (ATEX capacitive probes, ATEX GPS padlocks, gateways, tamper nodes, power protection, LiFePO4 backup, RS485 isolators, enclosures, wiring, tools).

Clear requirements:
Manufacturers of these hardwares with flexibility in pricing, OEM/Whitelabelling Options
RS485/Modbus integration for fuel probes.
GPS + cellular gateways with store‑and‑forward.
Smart locks that can be controlled remotely and capability to open only inside authorized geofences.
Secure MQTT/HTTPS telemetry to our backend (ThingsBoard PE + custom APIs).
Compliance awareness: NCC, SON, NMDPRA, NDPC (Nigeria Data Protection Act).

Scope of Work
A. Hardware Sourcing & Supplier Qualification
Identify and qualify suppliers for:
ATEX capacitive fuel level probes (RS485/Modbus).
ATEX smart GPS padlocks for discharge valve boxes.
Teltonika FMC130 or equivalent telematics gateways.
Intrinsically safe RS485 isolators, power modules, LiFePO4 batteries, enclosures, wiring, etc.

Verify:
ATEX/IECEx certificates (with certificate numbers and database links).
Modbus register maps and sample data frames.
API/protocol documentation for GPS locks and gateways.

Negotiate:
Prototype pricing (small MOQ since we are only prototyping and market validation).
OEM/white‑label options (our logo on devices and portals).
Sample lead times and shipping to Nigeria.

B. Firmware & Embedded Integration
Configure/integrate:
Teltonika FMC130 (or chosen gateway) for:
GPS, cellular, store‑and‑forward.
Reading RS485/Modbus sensors (fuel probes, tank sensors).
Sending telemetry to our MQTT broker / ThingsBoard instance.
ESP32‑based secondary node for:
Tamper detection (door/enclosure open, cable cut, power loss).
Local encryption and buffered telemetry.
Implement:
Robust power handling (12/24V truck systems, transients, reverse polarity).
Geofence‑based lock control (unlock only at authorized depots/stations).
Tamper alarms and offline caching.

Deliverables:
Configured gateways and ESP32 nodes ready for bench testing.
Firmware source code / configuration files and documentation.
Bench‑test reports (Modbus communication, power tests, cellular tests).

C. Backend/API Integration
Integrate hardware telemetry with our backend:
MQTT ingestion (devices → ThingsBoard / our broker).
Custom REST APIs (FastAPI/Node) for:
Trip/waybill management.
Reconciliation logic (loading vs delivery vs tank rise).
Alerting and incident workflows.
Regulator/insurer read‑only views.

Ensure:
Secure authentication (JWT/OAuth), role‑based access.
Multi‑tenant isolation (per customer).
Audit logs for all critical events.
Deliverables:
Working API layer connected to live devices.
Documentation (API specs, data models, sequence diagrams).
Sample dashboards/alerts demonstrating end‑to‑end flow.

Who Should Apply
Companies or teams with proven experience in:
Fuel monitoring / tanker telemetry / hazardous‑area IoT.
RS485/Modbus integration with fuel probes and tank sensors.
Teltonika/Queclink/Concox or similar telematics gateways.
GPS smart locks/e‑seals for trucks or containers.
Embedded engineers skilled in:
C/C++ for ESP32/STM32, ESP‑IDF or similar.
Power design for automotive/truck environments.
Cellular IoT and store‑and‑forward patterns.

Backend engineers skilled in:
Node.js/FastAPI, MQTT, PostgreSQL/TimescaleDB.
IoT platforms (ThingsBoard, AWS IoT, Azure IoT).
Secure API design and multi‑tenant systems.

Nice to have:
Experience with ATEX/IECEx projects or petroleum logistics.
Existing relationships with Chinese/Indian hardware manufacturers.
Familiarity with Nigerian telecom and regulatory environment.

How to Apply
In your proposal, please include:
Brief description of similar projects you’ve done (fuel monitoring, tanker tracking, GPS locks, etc.).
Examples of hardware you’ve integrated (probe models, gateway models, locks).
Links to GitHub/repos or demos (if available).
Whether you can help with hardware sourcing or only engineering.
Estimated timeline and budget for:
Hardware supplier qualification.
Firmware/embedded integration.
Backend/API integration.
We will prioritize teams that can show concrete, relevant experience and a clear plan to get the pilot running within a few weeks.