Introduction
Introduction
The bcMeter is an open-source optical absorption photometer designed to measure Black Carbon (BC) aerosols — commonly known as soot — in real-time. Whether you are monitoring ambient air quality in your neighborhood or measuring direct emissions from wood stoves, this device provides scientific-grade data at a fraction of the cost of reference instruments.
The device operates "headless" — it has no built-in screen. Instead, it hosts its own website that you can access from any smartphone or computer connected to the same network.
The software is open source: github.com/dahljo/bcmeter
Device Types
- bcMeter — Portable aethalometer for ambient Black Carbon measurement. Designed for stationary or mobile deployment in monitoring networks, citizen science projects, and field campaigns.
- eBcMeter — Emission measurement instrument for direct source sampling from wood-burning stoves and similar combustion sources. Uses microgram (µg) units instead of nanogram (ng).
How Does It Work?
- Polluted air is drawn through filter paper by a pump
- The filter paper absorbs black carbon (BC) particles
- An LED shining at 880 nm passes through the filter; a sensor measures the attenuation (reduction in light intensity)
- A separate reference channel monitors the same LED through a clean portion of the filter, compensating for environmental changes
- The attenuation is converted to BC concentration (ng/m³) using Beer-Lambert law
- Data is saved as CSV and displayed in real-time on the web interface
Multi-wavelength: Optional 520 nm and 370 nm channels enable source apportionment via the Ångström Exponent (AAE) — distinguishing between fossil fuel and biomass burning sources.
Sensors & Capabilities
Core
| Measurement | Sensor / Method | Notes |
|---|---|---|
| Black Carbon (BC) | Optical absorption at 880 nm | Primary measurement |
| Source apportionment | 520 nm, 370 nm | Ångström Exponent |
| Temperature / Humidity | SHT4x | |
| Airflow | Omron D6F differential pressure | Pump flow rate |
Optional Hardware
| Measurement | Sensor / Method | Notes |
|---|---|---|
| Temperature / Humidity / Pressure | BME280 | Barometric altitude |
| PM2.5 / PM10 | Sensirion SPS30 | Particulate matter |
| GPS | AT6668 UART | Position, altitude, speed |
| 4G Connectivity | SIM7080G LTE-M modem | Remote data upload |