CO2 Meter - A do-it-yourself carbon dioxide measuring ...
Transcript of CO2 Meter - A do-it-yourself carbon dioxide measuring ...
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CO2 Meter
A do-it-yourself carbon dioxidemeasuring device for the classroom
T. Dey, I. Elsen, A. Ferrein, T. Frauenrath, M. Reke, S. SchifferMakerspace of Faculty 5 (Electrical Engineering and Information Technology)& Mobile Autonomous Systems and Cognitive Robotics Institute (MASCOR)FH Aachen University of Applied Sciences
Int’l Workshop on AI and Digital Technologies in Coronavirus Pandemic and Beyond (COVID-19)at the PErvasive Technologies Related to Assistive Environments Conference (PETRA) 2021
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Motivation
Life with Corona
◮ Social distancing, lockdown measures, mutations
◮ Pupils have to undergo distance learning
Challenges & Deficiencies
◮ Especially younger kids cannot stay at home forever
◮ One-should-fit-all recommendations on ventilation
◮ Little information on risk in particular situation
Our Contribution
◮ Cheap but precise device for reliably measuring CO2 levels in classrooms
◮ Accessible self-assembly kit, also used as a vehicle for STEM education
◮ Connected device to collect more information and for analysis
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Background & Related Work
Background
◮ Corona precaution measures work (hygiene, distance, masks, ventilation)
◮ Transmission via aerosols → risk of infection particularly high indoors[Lednicky et al., 2020, Peng and Jimenez, 2020]
◮ Effects of distance learning [OECD, 2021], [Ravens-Sieberer et al., 2021]
◮ Current recommendations not flexible, not fitted for individual setting
Related Work
◮ CO2 as a proxy for aerosol level / air quality, e.g. [Johnson et al., 2018]
◮ Models for transmission of respiratory diseases[Riley et al., 1978, Rudnick and Milton, 2003, Dai and Zhao, 2020]
◮ CO2-based ventilation [Batterman, 2017, Pang et al., 2021]
◮ Our hardware approach is not unique, instead use common practices[Clements et al., 2017, Spinelle et al., 2017, Pino et al., 2019, Martin et al., 2017]
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CO2 Meter
Overview
◮ Measure current CO2 level via an NDIR sensor
◮ Display ventilation recommendation via Green-Yellow-Red LEDs
◮ Further information via LCD display (temp., rel. humidity, history, ...)
◮ Different modes of operation and connected via WiFi network
Features
◮ Designed as a do-it-yourself (DIY) kit
◮ Setup and config via web interface
◮ Display values via web GUI + display
◮ WiFi as an Access Point or as a client
◮ Data can be send to an MQTT server
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Sensor Selection & Kit Components
Sensor Selection
◮ VOC -vs- NDIR
◮ different vendors
◮ comparative evaluation 600
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suredC
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Temperature[°C]
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SCD30SensorIDsd8bfc014ac9cMHZSensorIDs483fda00180a
Kit Components
CO2 Sensor Sensirion SCD30
Microcontroller NodeMCU ESP8266-12F
Display 1,3 inch OLED I2C 128 x 64 pixels
Traffic Light LED Traffic Light Module
Real-time Clock DS3231 real-time clock
Power Supply USB Wall plug + Micro-USB cable
Clamps + Wiring Wago Connectors + Jumper Wires
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User Interface
User Interface Browser
User Interface Display
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Software System Architecture
WiFi
MQTT Broker
User Mobile
LocalDatabase
Sensor
Display
RTCNodeMCU
I²C
DIO
CO2 Meter
RemoteDatabase
CO2 Meter
AccessPoint
Internet
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OpModes & Connects
NoFi �þStandalone, no network, data only on device
LocalAP T Æ/§/B
Local Access Point, data via web UI
WiFi Client O T ƧB
Client in existing WLAN, data via web UI in LAN
WiFi Client + MQTT Client B§Æ T O T , / T � / A
Client in network, additionally data tx to MQTT serverData reporting and analysis possible (_ / ` / ^ / ÿ)
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Target Group and Training Material
Kit to interactively learn about technology
◮ Bonding with device through DIY kit
◮ No soldering, ok even for young learners
◮ Make technology tangible, HW -vs- SW
◮ Workshops by academic staff
◮ Parent projects, school clubs
Workshops & Videos as Training Material
Unboxing - Components
https://youtu.be/aAsCkTMjA_8
Assembly - Electronics
https://youtu.be/_UIu_xenOVU
Assembly - Chassis Box
https://youtu.be/eZ1lCGSWcG0
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Data Processing
MQTT Messages
1 {CO2Meter: {
2 "id": deadbeef_12345,
3 "temperature": 23.42,
4 "relhumidity": 42.00,
5 "co2levelppm": 815.0,
6 }
7 }
Data Portal
Data Analytics
◮ Collecting sensor values via MQTT
◮ Other data acquired seperately
◮ Backend works in real-time
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Conclusion
Summary
◮ A do-it-yourself carbon dioxide measuring device for the classroom
◮ Accessible, low-priced, extensible, easy to set up, connected system
◮ Immediate support for safe(r) in-person education in the pandemic
Work in Progress
◮ nearly 300 devices deployed in schools at different levels
◮ Currently preparing release of firmware source code
Outlook
◮ Pilot installations deployed, constantly increasing number of devices
◮ Device is beneficial beyond the pandemic (air quality + STEM edu)
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Team & Contact
Prof. Thomas Dey Prof. Ingo Elsen Prof. Alexander Ferrein
Prof. Tobias Frauenrath Prof. Michael Reke Dr. Stefan Schiffer
maskor.fh-aachen.de/co2meter
MASCOR Institute & FB 5 MakerspaceFH Aachen Univ of Applied SciencesEupener Str. 7052066 Aachen
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Bibliography I
Batterman, S. (2017).Review and extension of CO2-based methods to determine ventilation rates with application to schoolclassrooms.International Journal of Environmental Research and Public Health, 14(2).
Clements, A. L., Griswold, W. G., RS, A., Johnston, J. E., Herting, M. M., Thorson, J., Collier-Oxandale, A., andHannigan, M. (2017).Low-cost air quality monitoring tools: From research to practice (a workshop summary).Sensors, 17(11).
Dai, H. and Zhao, B. (2020).Association of infected probability of COVID-19 with ventilation rates in confined spaces: a Wells-Rileyequation based investigation.medRxiv.
Johnson, D. L., Lynch, R. A., Floyd, E. L., Wang, J., and Bartels, J. N. (2018).Indoor air quality in classrooms: Environmental measures and effective ventilation rate modeling in urbanelementary schools.Building and Environment, 136:185–197.
Lednicky, J. A., Lauzardo, M., Fan, Z. H., Jutla, A., Tilly, T. B., Gangwar, M., Usmani, M., Shankar, S. N.,Mohamed, K., Eiguren-Fernandez, A., Stephenson, C. J., Alam, M. M., Elbadry, M. A., Loeb, J. C.,Subramaniam, K., Waltzek, T. B., Cherabuddi, K., Morris, J. G., and Wu, C.-Y. (2020).Viable SARS-CoV-2 in the air of a hospital room with COVID-19 patients.medRxiv.
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Bibliography II
Martin, C. R., Zeng, N., Karion, A., Dickerson, R. R., Ren, X., Turpie, B. N., and Weber, K. J. (2017).Evaluation and environmental correction of ambient CO2 measurements from a low-cost NDIR sensor.Atmospheric measurement techniques, 10(7):2383–2395.
OECD (2021).The State of School Education.
Pang, Z., Hu, P., lu, X., Wang, Q., and O’Neill, Z. (2021).A smart CO2-based ventilation control framework to minimize the infection risk of COVID-19 in publicbuildings.preprint available athttps://www.researchgate.net/publication/349121056_A_Smart_CO2-Based_Ventilation_Control_
Framework_to_Minimize_the_Infection_Risk_of_COVID-19_In_Public_Buildings.
Peng, Z. and Jimenez, J. L. (2020).Exhaled CO2 as COVID-19 infection risk proxy for different indoor environments and activities.medRxiv.
Pino, H., Pastor, V., Grimalt-Álvaro, C., and López, V. (2019).Measuring CO2 with an arduino: creating a low-cost, pocket-sized device with flexible applications thatyields benefits for students and schools.Journal of Chemical Education, 96(2):377–381.
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Bibliography III
Ravens-Sieberer, U., Kaman, A., Erhart, M., Devine, J., Hölling, H., Schlack, R., Löffler, C., Hurrelmann, K.,and Otto, C. (2021).Quality of life and mental health in children and adolescents during the first year of the covid-19 pandemicin germany: Results of a two-wave nationally representative study.
Riley, E., Murphy, G., and Riley, R. (1978).Airborne spread of measles in a suburban elementary school.American journal of epidemiology, 107(5):421–432.
Rudnick, S. and Milton, D. (2003).Risk of indoor airborne infection transmission estimated from carbon dioxide concentration.Indoor Air, 13(3):237–245.
Spinelle, L., Gerboles, M., Villani, M. G., Aleixandre, M., and Bonavitacola, F. (2017).Field calibration of a cluster of low-cost commercially available sensors for air quality monitoring. Part B:NO, CO and CO2.Sensors and Actuators B: Chemical, 238:706–715.
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