---
title: "Guest Lecture in TTK4240 — Dust Sensing: From Photons to Data"
description: "Guest lecture at NTNU – \"Dust Sensing: From Photons to Data.\" Light scattering, the optical particle counter signal chain, and lessons from taking Arpuro from prototype to production."
---

<https://helpdesk.arpuro.io/arpuro-labs-as-blog>

# [Guest Lecture in TTK4240 — Dust Sensing: From Photons to Data](https://helpdesk.arpuro.io/arpuro-labs-as-blog/guest-lecture-in-ttk4240-dust-sensing-from-photons-to-data)

 Written by  | Jan 30, 2026, 11:48:00 PM

Geir Kulia gave a guest lecture in TTK4240 at NTNU walking from light scattering physics (Rayleigh, Mie, and geometric regimes; ISO 7708 dust fractions) through the full optical particle counter signal chain: photodiode, transimpedance amplifier, parallel comparator banks for size binning, and conversion from raw bin counts to mg/m³. The lecture closed with the parts of industrial sensor development that don't show up in coursework — EMC, IP-rated enclosures, ATEX/CE certification, gravimetric calibration, and supply-chain reality — drawn from the development of Arpuro, now deployed at ~20 industrial sites across Norway, Iceland, and Spain.

[View full post](https://helpdesk.arpuro.io/arpuro-labs-as-blog/guest-lecture-in-ttk4240-dust-sensing-from-photons-to-data)

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