Helvar

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Objective

The primary objective of the “Seeing the Light” project was to develop a functional prototype sensor for Helvar Oy that could accurately measure illuminance, determine the direction of incoming light, and differentiate between natural and artificial light sources. The sensor was to be designed as a compact, battery-operated device capable of transmitting data via Bluetooth Low Energy (BLE) advertisements. The project aimed to create a solution that could be integrated into Helvar’s existing systems, contributing to their research and development initiatives. Additionally, the project provided an opportunity for the student team to enhance their technical skills and apply theoretical knowledge in a real-world context.

Hardware Design

The NORA-B126 module with an integrated nRF5340 microcontroller was chosen to manage sensor data collection and Bluetooth Low Energy (BLE) transmission. The first prototype used five separate PCBs connected by flat wires, which later transitioned to a flexible circuit board (FCB) design for ease of assembly and cost efficiency.

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The final circuit board design features light sensors positioned to optimize data capture, while power components are assembled on both sides of the board. The design incorporates measures to protect sensor accuracy and ensure compatibility with the mechanical casing.

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Main Components:

    • NORA-B126: A low-power wireless module supporting BLE for reliable, long-range communication.
    • LTR-329ALS: A light sensor capable of measuring up to 64,000 lux, ideal for capturing ambient light levels.
    • TCS34725FN: An RGB color sensor with an integrated IR filter, providing accurate color and light detection.
    • I2C Multiplexer (TCA9548A): Used to expand the I2C bus to manage communication with multiple sensors.
    • LIS3MDL Magnetometer: Used to detect the direction of the light source through magnetic field measurements.

Enclosure Design

The final design was made to be compatible with the final version of the flexible PCB.The final version contains 3 parts: the cover case, the battery chamber and the closing panel of the battery chamber.

The cover case (Figure) contained slots that were specifically designed to mount the PCB. It is also made that the holes that have the sensor poke out have chamfer, so that the sensors have a good area to capture the data for the light.

The battery chamber (Figure) was designed to quickly change the battery without having to interact with other electronic components. The battery chamber has a hole to connect to the flexible PCB, and also holes that the battery holder can be locked into. The closing panel (Figure) is connected to the chamber via a turning mechanism, which is easy to use.

Software

The software was designed to manage sensor data acquisition, processing, and Bluetooth Low Energy (BLE) communication, built using Visual Studio Code and Zephyr RTOS. It interfaces with I2C sensors to collect and process data such as illuminance, colour temperature, and light direction, transmitting results via BLE, with optional AES-128 encryption for security. The modular code includes components for sensor management, data processing, and BLE communication, with real-time feedback and power management to optimize battery life. Despite successful integration with the nRF52 microcontroller prototype, challenges arose with the nRF53 due to its dual-core architecture, requiring significant restructuring. The system could detect light source types (natural or artificial), calculate light direction, and broadcast data via BLE.

Files

Helvar-FinalReport-2024

Project Helvar

Team Members

    • Vasilina Toporova
    • Artem Kiarkianen
    • Ben Nguyen
    • Kirill Levo
    • Huy Vu

License: MIT License