Difference between revisions of "Introduction"

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(Wiki update: sync with manual and dev docs (2026-03))
 
(Update: V1/V2 naming, remove ESP32/Pi distinction)
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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 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.


=== Hardware Variants ===
The software is open source: [https://github.com/dahljo/bcmeter github.com/dahljo/bcmeter]
 
The bcMeter is available in two hardware variants:
 
{| class="wikitable"
! Variant !! Platform !! Status !! Source
|-
| '''bcMeter''' (current) || ESP32-S3 || Production || Closed source (CC BY-NC 4.0)
|-
| '''bcMeter-dev''' || Raspberry Pi / Linux || Reference implementation || [https://github.com/dahljo/bcmeter-dev Open source]
|}
 
Both variants run the '''same web interface''' and provide the '''same measurement capabilities'''. This documentation applies to both — differences are noted where relevant.


=== Device Types ===
=== Device Types ===

Revision as of 14:21, 8 March 2026

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?

Working principle of a bcMeter.png
  1. Polluted air is drawn through filter paper by a pump
  2. The filter paper absorbs black carbon (BC) particles
  3. An LED shining at 880 nm passes through the filter; a sensor measures the attenuation (reduction in light intensity)
  4. A separate reference channel monitors the same LED through a clean portion of the filter, compensating for environmental changes
  5. The attenuation is converted to BC concentration (ng/m³) using Beer-Lambert law
  6. 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

Measurement Sensor / Method Notes
Black Carbon (BC) Optical absorption at 880 nm Primary measurement
Source apportionment 520 nm, 370 nm (optional) Ångström Exponent
Temperature BME280 / SHT4x Internal device temperature
Humidity BME280 / SHT4x
Pressure BME280 Barometric altitude
PM2.5 / PM10 Sensirion SPS30 (optional)
Airflow Omron D6F differential pressure Pump flow rate
GPS AT6668 UART (optional) Position, altitude, speed
Connectivity WiFi / 4G LTE-M (optional) SIM7080G modem