CO2 Trio Side by Side: Single Beam NDIR vs Dual Beam NDIR vs Photoacoustic

So many different types of sensors have become available in the market. For years we have seen and used Single (mainly) and Dual-Beam NDIR sensors for CO2 detection, but now another technology has surfaced, the Photoacoustic.

I decided to do a quick comparison of the different technologies in order to determine which one is the best and what are the differences if there is one. Price always affects the Bill of Material BOM, so we need to make a wise choice depending on the application of the sensor (commercial, real estate, industrial, scientific, etc).

Single and Dual Beam NDIR

CO2 is a gas with an asymmetric molecular structure that has strong absorption of infrared. This is the reason we use a Non-Dispersive Infrared NDIR sensor which is based on tunable diode laser spectroscopy.

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Review: Piera-7100 by Piera Systems

Recently, I shared an illustration that demonstrates, based on scientific research, how deep pollution particles can go into the human body.

Particulate matter (PM) are basically sneaky and invisible (to the naked eye) particles of various sizes that trigger inflammatory responses all over the human body depending on their size/origin and how deep inside us they can go. They are even able to destroy human tissue when the origin of the particles comes from the combustion of fossil fuel or biomass burning.

The smaller they get the easier it is to enter our bloodstream and affect every cell and organ in our body, even our brain. For this reason, it is very important to start monitoring the unregulated ultrafine particles aka nanoparticles or PM0.1 or UFP.

The IPS7100 by Piera Systems (a Canadian company) is a new generation low-cost laser scattering sensor capable of measuring those ultrafine particles PM0.1 but also fine particles PM0.3/PM0.5/PM1/PM2.5 and coarse particles PM5/PM10. In total, the 7100 series offers 7 output bins.

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uRADMonitor SMOGGIE-PM | Call for Volunteers Take 2 [Ended]

Back in 2019 uRADMonitor and I organized a “Call for Volunteers” where we gave away 10 monitors all around the world.

Once more we are looking for five volunteers who want to receive a Smoggie-PM monitor. The new version comes with new transparent icy look case and visual indication of the pollution concentration thanks to the LED light.

Volunteers all around the world who are willing to install an Air Quality Monitor in their backyard or balcony or window or any other outdoor environment in order to build a better air quality network and to help you raise awareness in your neighborhood/community.

The only requirement from your side is to have a good Wi-Fi internet connection 24/7 and keep the device on constantly in order to broadcast the measurements to an open map. The WiFi signal must reach the monitor outdoors.

Just email or tweet or DM me on any social media platform, tell me where are you planning to install the monitor and why should I choose you.


Smoggie-PM is an ultra low-cost high performance Air Quality Monitor, with Wi-Fi connectivity and a laser scattering sensor (Plantower PMS5003) that measures Particulate Matter PM1, PM2.5 and PM10 and makes it available on your phone or laptop in real time. Also, it is equipped with a Temperature/Humidity/Pressure sensor (Bosch BME280).

Smoggie is an automated, fixed, Air Quality monitoring station. It has WiFi connectivity to send the air quality measurements to the uRADMonitor Cloud in real time. It needs 5V to run, powered by a standard micro-USB cable (the same your smartphone uses in order to charge it). The new versions have a color LED light that reflect the pollution levels in real-time.

AQ Monitors meet Apple HomeKit

I really like to have all AQ Monitors and other devices connected to one place in order to make my life easier when I try to figure out what is going on in my house. I am an iOS user which means this post doesn’t concern Android users, however, I will advise you to stick around and read the benefits of having Apple HomeKit.

Not all AQ Monitor manufacturers support HomeKit and here comes HomeBridge which is a platform to bring non-supported devices to Apple’s ecosystem. There are only a few AQM manufacturers that officially support HomeKit, like Kaiterra, Eve and QingPing.

The community of the HomeBridge has allowed others to take advantage of the platform and make the user experience even better by porting many more AQMs into HomeKit.

Which AQMs support HomeBridge?

  • Airthings
  • PurpleAir
  • Awair
  • Sensor Community (aka Luftdaten)

How to set up HomeBridge?

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Review: Airthinx IAQ for Businesses

In a previous post, I presented Airthinx IAQ for Homeowners and how an advanced AQ monitor can be used for indoor environmental monitoring. In this post, we will explore how we can use the same monitor but in business environments (offices, industrial buildings, food supply chains, etc).

We will focus on the tools present in the dashboard as it is one of the best dashboards you will find in the market, and we will learn how to get the most out of it.

Let’s begin with the Dashboard – Home. Here we can create various types of widgets and arrange them according to our preference. First, you can see that I have created a column with all the current measurements with small graphs of the environmental parameters. Right next to it, I always watch for the general AQ, PM2.5, and Humidity. Below I have more widgets with other graphs and values that I want to have a glance.

Dashboard – Home

Next, we can see the Map tab. Here we can locate all the available monitors in a high precision as the monitors come with a GPS module, however, we will see later that we can manually set the location of the device.

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Series of Innovators: SPEC Sensors


SPEC Sensors was founded in 2012 in the USA (California) by Dr. Joseph Stetter and Ed Stetter. Their gas sensors, analog and digital, are one of a kind as the technology and hard work has allowed them to minimize the sensor size to only 20x20x3 mm in order for gas sensing to become a part of our everyday lives. The company has foreseen that sensors of all types are going to be integrated into smartphones and other wearable devices, becoming an integral part of our everyday lives and building the Internet of Things (IoT).

IoT low-cost sensors are in my DNA as I believe they will allow us to understand environmental issues otherwise, we would have dismissed or we would not be aware.

Let’s read together what they have to share with us and reach a conclusion at the end.


  • Tell us a bit about your motivation in developing air quality sensors?

We saw the need and opportunity for low cost electrochemical sensors with good performance – before SPEC, high performance sensors were too expensive and too big to enable new applications in wearables and distributed monitors. SPEC was born out of the research driven by Eco Sensors / KWJ Engineering, Inc. led by Dr. Joseph Stetter.  We were able to build SPEC Sensors using modern technology in a new high performance plastic package.Read More »

Building an IoT Air Quality Monitor that will survive the competition

Building a hardware startup is a hard business, we are well aware of that. Right now, there are a lot of indoor/outdoor Air Quality Monitors in the market that support low-cost sensors, unfortunately, even when the cost of the materials (aka BOM) is low, companies struggle to survive because of an initial bad business model.

If you want to enter into the game of the air quality or in general of the IoT, you have to ask yourself: How do I turn what I do into a compelling service?

When you sell a product you earn some money, typically three times more of what you have spent. However, your income relies only on that model and the problem with technology is that it evolves constantly, so tomorrow a new company will sell a product a bit better than yours because there will be a new sensor in the market and all future clients will shift their attention towards that device. Then you have to wait for a year or more in order to realize that you have to shut down your product and taking down with you a few hundred to thousand clients that have bought your AQM — More e-waste and frustration for the end-users.

For this reason, you have to invest in software development as well, and here comes my expertise. I have seen a lot of Air Quality Monitors, and I have collaborated with a fair number of companies in the field, but I always see the same mistake.

Some companies believe that they have to give customers free data support and services for life and if they turn their product into a paid service and they ask money based on a subscription model then they will lose costumers, but this is not necessarily correct. You are not going to ask someone to subscribe to your service to get just numeric values of a pollutant, you have to offer them something more than that. Something the competitors can’t offer because this feature is unique in your ecosystem. Maybe it could be restricted with a patent too.

Consumers really value good products especially when they can’t find something similar.

You are going to ask me, “What can I offer them?” You have two options, stay tuned for future articles or contact me in order to discuss how we can collaborate.


Series of Innovators: Insplorion

Starting with Insplorion AB, I am going to feature a series of articles about innovators in the field of air quality monitoring. My aim with these articles is to push the industry into the right direction. I don’t see air pollution as a way to make money but as a way to fix a problem, so by creating the right tools (sensors, air quality monitors, software, etc) we can shape the future towards a sustainable and less polluted environment.


Insplorion AB was founded in 2010 in Sweden, Europe by a team of professionals, Bengt Kasemo, Elin Larsson Langhammer, Christoph Langhammer and Igor Zoric. Although it is relatively a small company with less than 20 employees it is very active in nanotechnology, product research and sensor development. Insplorion’s core technology is the NanoPlasmonic Sensing (NPS),at least in my opinion, which you can read and learn how it works more on the interview below.


1. Tell us a bit about your motivation in developing air quality sensors?

We were approached by an entrepreneur who wanted to make a portable air quality device. He had scanned the market for all sensor technologies and not found any functional, especially for NO2. All current sensors were either too bulky, way too pricy or not sensitive or stable enough.  When we dug deeper into the field, we confirm the problem and saw that the unmet need in the expanding air quality sensor market fitted very well with our core advantages: sensitive yet robust, and easy to miniaturize. Read More »