PT. Bhinneka Rekayasa Teknologi

REF: BRT-CNG-2026-04

DATE: 28 APRIL 2026

CONFIDENTIAL

National Asset Telemetry
Architecture.

Deploying 1,000,000 active tracking units across the Indonesian archipelago requires an architecture explicitly designed for regional constraints, ranging from urban density in Jakarta to intermittent connectivity and high humidity in rural Kalimantan. Operational longevity is prioritized over complex engineering, utilizing a highly resilient hardware design to ensure continuous asset connectivity without manual intervention.

Prepared By

PT. Bhinneka Rekayasa Teknologi

15+ Years Enterprise Telemetry Expertise

Prepared For

Board of Directors

Project CNGR-IoT

1.0 Executive Summary

Engineered for the Archipelago

A

t a scale of one million units, a 1% hardware failure rate equates to 10,000 physical truck rolls. Every engineering decision within this proposal, including the removal of high-idle-current 4G LTE modems and the elimination of external microcontrollers, has been made to maximize field lifespan. By removing unnecessary complexity, potential points of failure are significantly reduced.

Standard IoT asset tracking solutions rely on continuous polling, complex architectures, and optimistic network assumptions. While these perform acceptably in controlled environments, they experience high failure rates when subjected to the heat, humidity, and variable network coverage typical of the Indonesian logistics ecosystem.

Bireka approaches the CNGR-IoT project by prioritizing operational longevity over unnecessary features. The firmware architecture is designed to react to physical interrupts rather than relying on continuous polling, with strictly locked basebands to prevent inefficient network scanning. Furthermore, standard LDO regulators are removed, connecting the SoC directly to the lithium thionyl chloride circuit, buffered by hybrid layer capacitors. This streamlined approach achieves a targeted 1-3 year operational lifespan on a single primary cell.

The Bireka Advantage

  • ✓ 15+ Years of custom hardware design and deployment in Indonesia.
  • ✓ In-house RTOS Expertise (ThreadX / Zephyr) for absolute firmware control.
  • ✓ Direct Quectel/ST Partnerships ensuring silicon-level support.
2.0 Performance Guardrails

The Metrics of Reliability

To achieve a targeted 1-3 year operational life on a single primary cell without intervention, the hardware and firmware must operate within incredibly strict, non-negotiable parameters.

1M
Unit Scale

National deployment size. Requires highly automated provisioning and dual-bank FOTA.

1-3yr
Lifespan

Powered by an 8,500mAh ER26500 C-Cell. No recharging, no battery swaps.

3.9µA
Deep Sleep

Absolute maximum quiescent current. Achieved by bypassing LDOs and powering down GNSS.

2.0A
EGPRS Burst

Peak current draw during 2G fallback transmission. Managed via SPC1520 Capacitor.

3.0 Hardware Architecture

The Silicon Foundation

We have frozen a Bill of Materials (BOM) designed explicitly to balance extreme cost constraints at a 1-million-unit scale against uncompromising industrial reliability.

Quectel BG95-M3 (SoC)

LTE-M / NB-IoT / 2G + GNSS

The brain of the system. We utilize the OpenCPU (ThreadX) environment to eliminate the need for an external MCU, significantly reducing unit economics and shrinking the quiescent current footprint.

STMicroelectronics (SIM)

ST4SIM-201M (MFF2)

A soldered discrete eSIM chip. We explicitly rejected the iSIM variant to guarantee 2G fallback capability. Soldering prevents vibration-induced disconnects inherent to plastic nano-SIM slots.

ST LIS2DW12 (Sense)

Ultra-Low Power Accelerometer

Operates at just 0.38µA. This sensor acts as the hardware interrupt, waking the main BG95 processor from PSM *only* when physical movement of the CNG cylinder is detected.

Passive GNSS Patch Antenna

Zero Vampire Current

We explicitly designed out active LNA-based GNSS antennas. A passive patch antenna ensures zero parasitic current draw while the device is in its sleep cycles, trading a few seconds of acquisition time for years of battery life.

flowchart LR B[ER26500 Battery
8,500mAh] -->|Trickle Charge| C(SPC1520 HLC) C -->|2A Burst| M{Quectel BG95-M3
OpenCPU} S[ST LIS2DW12
Accel] -.->|Hardware Interrupt| M M <-->|Auth| SIM[ST4SIM-201M] M ===>|NB-IoT / 2G| ANT((Antenna)) classDef component fill:#ffffff,stroke:#1D4ED8,stroke-width:1px,color:#0F172A classDef power fill:#F8FAFC,stroke:#EA580C,stroke-width:1px,color:#0F172A class B,C power class M,S,SIM,ANT component

Figure 1.0: High-Level Hardware Integration Schematic

Physical Layout & Component Topology

Scale: 1mm = 10px
55.0 mm 45.0 mm E1 Meander Antenna QUECTEL BG95-M3 LTE-M / NB-IoT / 2G SoC ANT1 GNSS eSIM ST4SIM-201M ACCEL 100µF 7343 V+ AIN GND J1 HEADER TVS BOTTOM LAYER + - BT1 - EVE ER26500 (C-Cell) Primary Li-SOCl2 Battery - 8500 mAh C_SPC1 - EVE SPC1520 Hybrid Layer Capacitor (2A Burst) FR4 PCB (1.6mm) QUECTEL BG95-M3 (2.4mm) GNSS PATCH (4mm) J1 (8.5mm) ER26500 BATTERY (26.2mm) SPC1520 (15mm) 26.2 mm

Interactive Hardware Blueprint

Hover over any component footprint on the board to view critical technical specifications and integration constraints.

4.0 Electrical Engineering

Mastering the 2A Pulse

The primary cause of failure in remote IoT devices is not dead batteries, but Under-Voltage Lockout (UVLO). Because Indonesian networks often require the BG95-M3 to fall back to 2G (EGPRS), the radio will periodically demand savage 2.0 Amp transmission bursts. A standard ER26500 battery cannot deliver 2A; the voltage will instantly collapse, resetting the processor and effectively bricking the device.

The HLC Solution

We pair the primary battery in parallel with an SPC1520 Hybrid Layer Capacitor. The battery trickles charge into the capacitor, and the capacitor acts as a reservoir, dumping the necessary 2A peak current to the modem without voltage sag.

Decoupling Array

VBAT_RF Bulk High-Capacitance Tantalum
VBAT_RF Filter Multi-Stage Ceramic
VBAT_BB Filter High-Frequency LC Array
Power Path DIRECT (No LDO)
5.0 Geographic Constraints & Network Topology

The Perfect Network Compromise

Indonesia's vast archipelago presents a unique telemetry challenge. Before arriving at our final architecture, Bireka engineering evaluated multiple transmission vectors. We concluded that an NB-IoT primary with 2G (GPRS) fallback is the only viable compromise for a reliable multi-year lifespan across all provinces.

✗ 4G LTE (Cat-1)

Idle current is far too high to support the targeted multi-year lifespan.

✗ Pure NB-IoT

Incredible efficiency, but guarantees failure outside major Javanese metro areas.

Selected

✓ NB-IoT + 2G

Ultra-low-power NB-IoT falling back to ubiquitous 2G GPRS for national coverage.

Motion-Gated Telemetry Cycle

To preserve the battery over multiple years, continuous time-based polling is disabled. The device transmits location data exclusively when physical transit is detected by the accelerometer. When immobilized at a customer site or depot, the hardware fully powers down, waking only once every 24 hours to transmit a minimal heartbeat payload to confirm operational status.

Strict PLMN Locking

We utilize baseband-level carrier locking to bind the modem exclusively to the Telkomsel network. If a device loses signal in rural Sumatra, it will not waste hundreds of milliamps attempting to scan competing bands it isn't authorized to use.

Exponential Backoff

If attachment fails on both NB-IoT and 2G after 120 seconds, the firmware forces the radio into deep PSM. It will not try again for 1 hour, then 4 hours, then 24 hours. The device must survive the transit, not drain the battery crying for a tower.

Ultimate SMS Fallback

While 2G (GPRS) provides the primary IP-based data connection, the system is designed with a final failsafe. If IP data bearers completely fail but GSM signaling remains active, the firmware will transmit critical location payloads via raw SMS, ensuring data delivery even under catastrophic network degradation.

Cell-ID Pre-Check (LBS)

Before powering the high-drain GNSS subsystem, the modem performs a fast, low-power Cell-ID check against the cellular tower. If the cylinder hasn't moved beyond a 2km radius since its last fix, the device immediately returns to sleep, saving the massive power cost of a redundant satellite fix.

Dual-Bank Delta FOTA

Firmware Over-The-Air (FOTA) updates are designed around a dual-bank partition strategy. If a corrupted update is downloaded over a weak field connection, the system automatically rolls back to the previously known-good partition, guaranteeing zero bricked units in the field.

stateDiagram-v2 direction LR [*] --> Wakeup: Accel Trigger Wakeup --> ScanNB: NB-IoT Scan ScanNB --> Transmit: Signal Found ScanNB --> Scan2G: Timeout (60s) Scan2G --> Transmit: Signal Found Scan2G --> Sleep1: Timeout (60s) Transmit --> Sleep24: ACK Received Sleep1 --> Wakeup: 1hr Backoff Sleep24 --> [*]: Deep Sleep

Figure 5.0: Firmware Network Fallback State Machine

6.0 Intrinsic Safety

CNG Environment Compliance

Deploying active electronics onto Compressed Natural Gas (CNG) cylinders requires strict adherence to intrinsic safety principles to prevent ignition risks.

Total Encapsulation (Potting)

The PCB assembly will be fully encapsulated using an industrial potting compound. This mitigates arcing risks, insulates the circuit from moisture, and provides structural shock resistance during cylinder transit.

Direct Cylinder Embedding

Custom enclosures are out of scope. The potted circuit boards are designed to be embedded directly into the HDPE (High-Density Polyethylene) structure of the cylinders themselves, ensuring a seamless, tamper-proof integration without external mounting brackets.

Installation Methodology Evaluation

During engineering reviews, two primary approaches were evaluated for integrating the telemetry circuit into the CNG cylinder: inserting the sensor during the carbon filament winding process, versus post-production cavity potting (the original baseline). An objective risk-benefit analysis was conducted to determine the superior method for million-unit scale.

Approach A: Filament Winding Insertion

Theoretical Pros
  • Potential for deep structural integration within the composite layers.
Critical Cons
  • Mechanical Stress: Circuit integrity is compromised when subjected to extreme pressure and bending forces from carbon filament tension during the winding process.
  • Thermal Catastrophe: The cylinder curing process requires sustained temperatures of 120C. This guarantees catastrophic failure of the Li-SOCl2 battery and thermal degradation of delicate sensors.
  • Antenna Misalignment: The sensor is buried under layers of composite material while the cylinder rotates continuously. It becomes nearly impossible to guarantee that the NB-IoT antenna remains perfectly oriented outward, leading to degraded signal transmission.
  • Process Interruption: Halting the automated winding line to manually install sensors introduces severe manufacturing inefficiencies and adds significant production time per cylinder.
Recommended

Approach B: Post-Production Potting

Proven Pros
  • Zero Thermal Shock: Electronics are installed after the 120°C curing process, ensuring the battery chemistry and solder joints remain perfectly intact.
  • Ultimate Protection: Industrial potting compound sets the circuit firmly in the cavity, absorbing physical shocks and completely sealing out moisture without external mechanical stress.
  • Precise Antenna Alignment: Inserting the device into a pre-formed cavity after production allows for exact, uniform placement. The antenna's orientation is perfectly controlled to maximize network reach.
  • Maximum Throughput: Does not interrupt the carbon winding phase, allowing for streamlined, high-speed cylinder manufacturing.
Manageable Cons
  • Requires pre-planning the precise sensor cavity dimensions during the initial cylinder mold design.

Final Verdict: Post-Production Potting

While embedding the circuit during the carbon winding phase may seem structurally appealing, it introduces catastrophic points of failure. The physical compression from carbon filaments risks fracturing the PCB, the 120C curing cycle fundamentally exceeds the thermal limits of the Li-SOCl2 battery, and the rotational process eliminates any control over antenna orientation. Post-production potting within a pre-formed cavity is objectively the superior method, delivering maximum protection and perfect RF transmission without compromising manufacturing efficiency.

Optional Add-on: Valve-Integrated Low Pressure Alert

If the operational model requires an automated alert when gas pressure drops below a critical threshold (e.g., 20 bar) to proactively dispatch a replacement, a Mechanical Pressure Switch can be integrated into the cylinder's main brass valve. Unlike continuous analog MEMS sensors, this switch operates as a "dry contact." It remains open under high pressure and physically closes when the pressure drops, instantly sending a hardware interrupt that wakes the Quectel BG95 from deep sleep to transmit the alert.

Strategic Advantages

  • Zero Power Consumption: Consumes exactly 0.0µA while waiting for the pressure drop, guaranteeing the 10-year battery life requirement without the continuous energy drain of analog sensors.
  • Flawless Intrinsic Safety: A dry contact switch easily passes ATEX certification. With simple current-limiting pull-up resistors on the PCB, it is physically impossible for the circuit to generate an ignition spark, even if the wire is severed.
  • Firmware Simplicity: Eliminates complex ThreadX continuous polling cycles, ADC scaling constraints, and the need for algorithmic temperature compensation routines.

Operational Trade-offs

  • Binary Data Limitation: Provides only a single binary event (High/Low) rather than a continuous, real-time pressure decay curve. It cannot tell you "how much" gas is left, only that it is "low."
  • External Wiring Route: Requires a ruggedized, intrinsically safe wire to run externally from the brass valve assembly down into the potted IoT cavity. This introduces a mechanical linkage that must be protected from physical damage during cylinder transit.
7.0 Execution Strategy

Target Cost & Timeline

Designed for the 1,000,000 unit tier, Bireka has engineered the unit economics to be highly competitive while maintaining industrial reliability.

M1

Prototyping & PoC

1 Month dedicated to schematic design, PCB fabrication, and Proof of Concept validation.

M2

Mass Production Prep

1 Month to finalize the supply chain, prepare the circuit manufacturing lines, and lock the BOM.

We hope this architecture document demonstrates our deep understanding of the CNGR-IoT mandate. We have the full capability, technical team, and supply chain readiness to execute this massive rollout.

Sincerely,

Jati Indrapramasto

CEO, PT. Bhinneka Rekayasa Teknologi