Embedded systems.
Built for the real world.

Hardware, firmware and connected systems — engineered from schematic to deployment.

ESP32 / STM32 · PCB Design · Industrial IoT · Firmware · Linux SBCs

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01Projects

Selected engineering.

SentinelBus-DC industrial SNMP monitor PCB top view
01Industrial Environmental Monitor

SentinelBus-DC

Data centre environmental monitoring over SNMP, powered directly from a 48–72V telecom bus rail.

Purpose
Data centre and telecom rooms need temperature, humidity, smoke and door/leak status delivered into existing NMS tooling — without adding a separate power supply or a proprietary dashboard.
System
A custom PCB that aggregates up to 32 distributed Modbus RTU sensor nodes over a galvanically isolated RS-485 bus spanning up to 1200 m, and exposes the aggregated data through a native SNMP v1/v2c agent on hardwired Ethernet. Four optoisolated dry-contact outputs and four isolated digital inputs interface directly with door contacts, leak detectors and UPS fault signals.
Role
Schematic capture and multi-layer PCB layout in Altium Designer · Isolated power architecture and bus protection · Firmware: Modbus RTU master, SNMP agent and custom MIB · Bring-up, bench validation and NMS integration testing
Hardware
ESP32-S3 application processor · Isolated DC-DC converter, 48–72V DC bus input · Galvanically isolated RS-485 transceiver
Firmware
Modbus RTU master polling up to 32 sensor nodes · SNMP v1/v2c agent with GET, TRAP and custom MIB support · Compatible with Zabbix, PRTG and Nagios out of the box
Interfaces
RS-485 / Modbus RTU · Ethernet (SPI, W5500) · SNMP v1/v2c · Dry contact DI/DO
Considerations
Maintaining galvanic isolation across the RS-485 bus, digital I/O and the DC input while keeping the board compact
  • ESP32-S3
  • W5500
  • RS-485
  • Modbus RTU
  • SNMP
  • Altium Designer
Full case study
Signal chain
  1. 01Modbus RTU sensor nodes (≤32)
  2. 02Isolated RS-485 bus (≤1200 m)
  3. 03ESP32-S3
  4. 04W5500 Ethernet
  5. 05SNMP v1/v2c agent
  6. 06NMS (Zabbix / PRTG / Nagios)
IsoGuard-48 PCB layout render
02Industrial Telecom Node

IsoGuard-48

Monitoring and control node for telecom enclosures — smoke, flood and temperature sensing with multi-interface communications.

Purpose
Remote telecom enclosures run from a −48V rail and need environmental sensing plus contact monitoring that survives the electrical environment they sit in.
System
An industrial-grade node built around the ESP32-S3, powered from an isolated −48V input, with isolated RS-485 communications and more than twelve dry-contact channels for sensors and status signals.
Role
Hardware architecture, schematic and PCB layout · Isolated power and input protection design · Firmware for sensing, contact monitoring and communications · Prototype bring-up and validation
Hardware
ESP32-S3 application processor · Isolated −48V input stage · Isolated RS-485 transceiver
Firmware
Sensor acquisition and contact-state monitoring · RS-485 based communications · Event reporting and threshold handling
Interfaces
RS-485 · Dry contacts · Analog / digital sensor inputs
Considerations
Isolating a −48V telecom rail from low-voltage logic on a compact board
  • ESP32-S3
  • RS-485
  • −48V Isolated
  • Altium Designer
Full case study
Signal chain
  1. 01Smoke / flood / temperature sensors
  2. 0212+ dry-contact channels
  3. 03ESP32-S3
  4. 04Isolated RS-485
  5. 05Supervisory system
ESP32 IoT gateway assembled board inside IP-rated enclosure
04Industrial Gateway

ESP32 IoT Gateway

Enclosed gateway with Wi-Fi, BLE and wired Ethernet failover, sensor aggregation and three relay channels.

Purpose
Industrial and commercial deployments need a single gateway that can reach the network by whichever interface is available on site, and drive local loads.
System
A fully enclosed gateway on the ESP32-WROOM-32D supporting Wi-Fi, BLE and wired Ethernet via an HR911105A magnetics-integrated jack, with automatic fallback between Ethernet and Wi-Fi. BLE is used for local provisioning without a network. UART ultrasonic sensors plus 1-Wire and analog temperature inputs publish to AWS IoT Core and Firebase Realtime Database. Three SONGLE relay channels (10 A / 250 VAC) drive motor, light and auxiliary loads. 9–24 V DC input, IP-rated enclosure, external SMA antenna.
Role
Hardware design and enclosure integration · Ethernet, wireless and antenna provisioning · Firmware for connectivity fallback, sensor acquisition and cloud publishing
Hardware
ESP32-WROOM-32D module · HR911105A Ethernet jack with integrated magnetics · 3× SONGLE relays, 10 A / 250 VAC
Firmware
Automatic Ethernet ↔ Wi-Fi fallback · BLE provisioning for local configuration · UART ultrasonic, 1-Wire and analog temperature acquisition
Interfaces
Ethernet · Wi-Fi · BLE · UART · 1-Wire · MQTT
Considerations
Seamless failover between wired and wireless interfaces without dropping cloud sessions
  • ESP32
  • Ethernet
  • BLE
  • MQTT
  • AWS IoT
  • FreeRTOS
Full case study
Signal chain
  1. 01UART ultrasonic / 1-Wire / analog temperature
  2. 02ESP32-WROOM-32D
  3. 03Ethernet ↔ Wi-Fi failover
  4. 04MQTT
  5. 05AWS IoT Core / Firebase RTDB
02Additional Work

More engineering projects.

Smart lock IoT node PCB render
Connected Access Control

Global Smart Lock

Production smart lock for industrial and telecom sites with 4G LTE remote access and tamper detection.

LTE / 4G · MQTT · UART

ESP32-S3 PZEM power monitor PCB render with four relay channels
Energy Metering & Relay Control

ESP32-S3 AC Power Monitor

Mains-powered board streaming live AC energy parameters to the cloud with four relay channels for load control.

UART / Modbus RTU · Wi-Fi · MQTT

Arduino Mega custom PCB render with 16 level-shifted 12V outputs
High Channel-Count Control Board

Arduino Mega 12V I/O Expander

ATmega2560 board with sixteen level-shifted 12 V outputs, thermal cutoff protection and active fan control.

SPI · UART (USB-to-TTL) · Analog / 1-Wire temperature

03Experience

Professional experience.

2025 — Present

Krypton Solutions

Solution Engineer

  • Lead R&D on anti-theft solutions meeting industry security and reliability standards.
  • Firmware development on STM32 and ESP32 platforms for stability and performance.
  • Schematics and PCB layouts for commercial products, from specification to manufacture.
  • Wi-Fi, BLE and LoRa connectivity for remote monitoring and control.
2021 — 2025

Octathorn

Embedded Design Engineer

  • End-to-end embedded firmware and hardware for international clients.
  • Optimised systems for performance, stability and cost-efficiency.
  • Integrated networking and IoT features for remote device management.
2015 — 2019

University of Engineering & Technology, Taxila

B.Sc. Electrical & Computer Engineering

04Capabilities

Technical capabilities.

Embedded

  • C / C++
  • ESP32
  • STM32
  • ESP-IDF
  • FreeRTOS

Hardware & PCB

  • Altium Designer
  • Schematic Design
  • PCB Layout
  • Hardware Bring-up
  • Debugging

Industrial Communications

  • RS-485
  • Modbus RTU / TCP
  • CAN
  • Ethernet
  • SNMP

Connectivity

  • Wi-Fi
  • BLE
  • LoRa
  • LTE / 4G
  • MQTT
  • AWS IoT
  • Firebase

Linux SBCs

  • Raspberry Pi
  • Linux
  • Python
  • Bash
  • GPIO / SPI / I²C

Interfaces

SPI · I²C · UART · USB · 1-Wire · PWM

05Approach

Engineering approach.

01

Hardware first principles

Power, protection, interfaces and system constraints are considered from the beginning of the design.

02

Firmware built around the system

Firmware architecture, communications and device behaviour are developed around the requirements of the actual hardware.

03

Design through validation

Requirements → architecture → schematic → PCB → firmware → bring-up → testing → deployment.

06About

From requirements to deployment.

Around five years of professional embedded engineering experience, working across the full embedded product lifecycle — hardware architecture, schematic capture and PCB layout, firmware, communication interfaces, bring-up, debugging and deployment.

  1. Requirements
  2. Architecture
  3. Schematic
  4. PCB
  5. Firmware
  6. Communications
  7. Bring-up
  8. Debugging
  9. Deployment
07Contact

Get in touch.

For embedded systems, hardware design, firmware or industrial IoT opportunities.

LinkedIn
Rana Hassan