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CO2 Detector with Lime

GSS Adds Interface To CO2 sensor

The Internet of Things (IoT) is creating many new exciting application opportunities to create smart environments where sensors monitor for changes so that the appropriate actions can be taken. The fastest growing examples of this are HVAC (Heating Ventilation and Air Conditioning), IAQ (Indoor Air Quality), smart homes and smart offices where a network of sensors monitors temperature and carbon dioxide (CO2) levels to ensure the optimal conditionals are maintained with the minimum of energy expenditure. A challenge for such systems in that the CO2 sensors need mains power to operate incurring costs for cabling and, in the case of installing in existing buildings, redecoration.

 

Gas Sensing Solutions (GSS) has solved this problem with its low power, LED-based sensor technology. The sensor’s power requirements are so low that wireless monitors can be built that measure CO2 levels as well as temperature and humidity with a battery life of over ten years. Being wireless means that they can be placed wherever they are required with no need for cabling or disruption and simply relocated as building usages changes

 

CO2 Detector with Lime

GSS CozIR-LP with I2C interface

To make the design of these monitors even easier, GSS has added an I2C interface to its very low power CO2 sensor, the CozIR®-LP. Having the widely used I2C interface now makes the integration of the sensor into a design very easy. The CozIR®-LP is the lowest power CO2 sensor available requiring only 3mW that is up to 50 times lower than typical NDIR CO2 sensors. The GSS patented LED technology also means that the solid state sensor is very robust.  This keeps maintenance costs to a minimum as the expected lifetime is greater than 15 years making them the perfect choice for fit and forget applications that measure low (ambient) levels of CO2 from 0-1%.

“Although HVAC and IAQ are major application areas,” explained Calum MacGregor, CEO at GSS, “the lightweight, miniature size of the CozIR-LP also opens up other new possibilities for CO2 monitoring such as portable and wearable devices. The power requirements are so low that energy harvesting designs, such as solar, are now easily achievable. Here again, the new feature of an I2C interface will simplify the design process of integrating the sensor with other sensors and devices all on the I2C bus.”

 

GSS will be launching the new I2C-enabled CozIR®-LP on booth C5366 at the AHR Expo in Atlanta, GA, USA on the 14-16 of January 2019. https://ahrexpo.com/

 

GSS technology

Most CO2 sensors work by measuring how much light is absorbed by CO2 molecules in the 4.2 to 4.4 microns range as it passes through the sample gas, which is called Non-Dispersive Infra Red (NDIR) absorption. The amount of absorption indicates how much CO2 is present. GSS developed proprietary LEDs that are specifically tuned to emit at these wavelengths. The LEDs use very little power and turn on almost instantly, enabling sensor readings to be made in a few seconds. As a result, GSS has pioneered the development of CO2 sensors that can be powered by batteries for long periods of up to ten years. Competitor sensors use IR sources that require significantly more power per measurement and also take much longer to reach a stable condition for a measurement, resulting in the need for mains power.

 

 

Low power CO2 sensor demo

GSS Sensor China Exhibition

Gas Sensing Solutions (GSS), a leader in CO2 sensor technology, will be exhibiting at Sensor China Expo 2018 . The company will be on Booth B004 in the Overseas Pavilion from 10 to 12 September 2018.

“China is one of our largest export markets,” said Lily Liu, Business Development Manager at GSS. “We make regular trips to China to support our partners with technical training and advice on designing solutions using our sensors. Naturally, we will also be talking to manufacturers seeking the very best in CO2 sensor technology, as our next generation LED-based sensors set new standards for low power, fast response and robustness.”

Low power CO2 sensor demo

How the CozIR-LP CO2 sensor can be used for Demand Controlled Ventilation (DCV) applications

GSS has a multi award-winning technology that is the basis for its next generation CO2 sensors. Its proprietary mid-infrared LEDs use very little power and turn on almost instantly – giving sensor readings in less than a second. As a result, GSS has pioneered the development of solid-state NDIR CO2 sensors that can be powered by batteries for up to 15 years. Alternative sensors use IR sources that require significantly more power per measurement and also take much longer to reach a stable condition for a measurement, resulting in the need for mains power. Also, being solid-state means that GSS sensors are very robust and stable enabling them to be used in harsh conditions of vibration and pressure changes, such as on vehicles, aircraft or even spacecraft.

GSS has three families of standard products that each focus on a particular strength of its technology. Therefore, designers can select the most appropriate sensor according to the needs of their specific application. The CozIR® family has particularly low power consumption and so provides a long term, low maintenance solution for battery-powered ambient air monitoring systems.

CozIR-LP low power and small CO2 sensor

CozIR-LP low power, small profile CO2 sensor

SprintIR high speed co2 sensor

SprintIR-W high speed sensor

The SprintIR® family provides high speed sensing up to 100% CO2 concentration, for when an ultra-fast measurement result is required. And the ExplorIR® brand is for measuring up to 100% CO2 levels in tough applications, such as those subjected to harsh environments, vibrations, and handling.

100% co2 sensor for tough applications

ExplorIR-W robust sensor

Within each family there are further sub-brands according to specific features, such as size, output and Temperature + Relative Humidity (RH) integration. As the company manufactures its sensors, it also offers a custom CO2 sensor design service.

GSS will have demonstrations on its stand to showcase these three strengths. The CozIR®-LP shows how a battery-powered CO2 sensor can be used for Demand Control Ventilation. The SprintIR®-6S demo shows how fast the sensor responds to changes in CO2. The ExplorIR® robustness is proven by having it working inside a ball being thrown around the stand.

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If you would like to meet GSS at the show, please contact us: info@gassensing.co.uk

Find out more about the Sensor China Expo here: http://www.sensor-expo.com/en/

Connections

Monitor CO2 Levels With BBC Micro:Bit

Written by Martin Woolley | http://www.bittysoftware.com

Visualising the Invisible!

I was recently contacted by a professional educator, based in Alberta, Canada called Jennifer Ferguson. Jennifer (@FergeeksonGirl ‏ on Twitter) works for a charitable, education and outreach organization called Let’s Talk Science (@LetsTalkScience) and has been using Bitty Data Logger.

The reason Jennifer made contact was to talk about her current project, Living Space, an education initiative developed with the Canadian Space Agency, and to ask for some assistance.

Living Space is concerned with monitoring key environmental conditions, including carbon dioxide (C02) levels. Jennifer wanted to be able to connect a Carbon Dioxide sensor to a micro:bit and to communicate its readings to Bitty Data Logger over Bluetooth so that the data could be visualised, logged and shared.

C02 Monitoring

C02 monitoring is widely used in all sorts of applications, many of them really important, some of them surprising. Examples include heating, ventilation and air conditioning (HVAC) systems, large scale city environmental monitoring, and aspects of food production, including monitoring of plant cultivation environments and improved food storage. It’s used in laboratory incubators for monitoring cell cultures, and in healthcare for things like breath analysis applications where the sensor has to deliver results very rapidly, at around 20 measurements per second. Breath analysis data allows for monitoring conditions such as asthma. And of course, a C02 sensor being a sensor, it’s something you’d expect to find in larger scale connected systems which we might file under the umbrella term “Internet of Things (IoT)”.

Jennifer was working with an impressive sensor, the CozIR®-A made by Scottish company GSS (Gas Sensing Solutions). Some models, such as this one can take temperature and humidity readings as well as C02 measurements.

GSS CozIR®-A low power ambient air CO2 sensor

CozIR®-A ambient air CO2 sensor

Let’s start by getting to know the CozIR®-A sensor.

Connecting a micro:bit to the CozIR®-A Sensor

The CozIR®-A sensor has a number of pins on its underside. The important ones are GND,  3.3V power and serial receive (RX) and transmit (TX) pins. Yes, the interface is a UART interface, which allows serial communication, one bit at a time using two of the pins, one for transmitting bits and one for receiving. To connect the CozIR®-A sensor to a micro:bit, you make connections like this:

CozIR®-AMicro:bit
GNDGND
3V33V
TXRX (pin 1)
RXTX (pin 0)

Note how TX on the CozIR®-A is connected to RX on the micro:bit and RX to TX. This makes sense if you think about it. Data transmitted from the sensor has to be received by the micro:bit. Data transmitted by the micro:bit has to be received by the sensor.

Here’s what a micro:bit connected to a GSS CozIR®-A sensor looks like:

Connections

micro:bit connected to CozIR®-A CO2 sensor

close-up of the micro:bit connected to CozIR®-A CO2 sensor

Close-up of micro:bit with connections

GSS CozIR®-A CO2 sensor with connection

Close-up of GSS CozIR®-A CO2 sensor

Communicating with the CozIR®-A Carbon Dioxide Sensor

The GSS CozIR®-A sensor uses a simple protocol for sending and receiving data and commands over the UART connection with a microcontroller like our micro:bit. All commands and data consist of ASCII characters only and they’re all, always terminated with carriage return, line feed characters i.e. \r\n or ASCII characters 0x0D and 0x0A.

The software guide that comes with the GSS CozIR®-A sensor is very good, and it doesn’t take long to understand the protocol and pick out those commands and responses that are required for your purposes.

There are three operating modes defined. Mode 0, Command Mode stops the sensor from making measurements. It will respond to commands when it receives them, but otherwise is more or less dormant. Mode 1, Streaming Mode has the sensor making and reporting measurements every 500ms by default. Mode 2, Polling Mode makes measurements in the background but does not report them unless it receives an appropriate command from the connected micro:controller.

To request a particular mode #, the command K #\r\n must be sent. So for polling mode, the command is K 2\r\n. Note the space character between “K” and “2”.

For the best, most accurate readings, the sensor needs to be calibrated. The protocol supports calibrating the sensor in a number of ways, including in a known gas concentration, which is the recommended approach or, for those of us without a supply of a suitable reference gas, in fresh air.

Requesting fresh air calibration is achieved by sending the command G\r\n to the sensor.

Micro:bit and the CozIR®-A Sensor

Jennifer had already put together a MakeCode application which could acquire sensor readings from the CozIR®-A and display them on the micro:bit’s LED display. Her application made use of a handy custom block written by Simon Monk of Monk Makes that took care of the nitty gritty details of talking to the sensor, which made her application very easy to read. Here’s the original code which she sent to me:

MakeCode application code for co2 monitoring

MakeCode original code

The application starts by configuring the micro:bit serial communications system to use pins 0 and 1 from the edge connector instead of using the USB connector for serial data. It then sits in an infinite loop, calling one of three custom block functions to obtain a C02, temperature or humidity reading, depending on the value of a variable called mode. The mode variable can be changed by pressing button A so that you can switch from C02 to temperature to humidity readings at the click of a button. Values returned by the custom block are simply displayed on the micro:bit LED grid.

The CozIR®-A Custom Block and Serial Communications

The CozIR®-A custom block which the Let Talk Science application uses, works like this.

There are a number of functions which the application using the block will call, such as the function C02(). Functions like this one send a command to the sensor (in this case Z \r\n) by writing to the serial interface, wait for 200ms and then return the value of a variable which should now contain the latest measurement of the requested type.

    export function Co2(): number {

serial.writeString(“Z\r\n”)

basic.pause(200)

return co2

}

 

How the variable gets assigned the latest measurement, is explained by looking at another part of the custom block’s code. Responses to all commands are received from within an event handler, serial.onDataReceived which is called whenever there’s data waiting to be read from the serial port, as will be the case when a command has been processed. The response data gets read into a string variable, examined to see what type of response it is and then values extracted and assigned to the appropriate variable. For example, C02 readings always start with a Z then a space and then the value in parts per million (ppm). So this code checks for a response that starts with “Z” and then extracts the associated value:

response = serial.readUntil(serial.delimiters(Delimiters.NewLine))

//basic.showString(response)

value_str = response.substr(3, 5)

let value = parseInt(value_str)

// basic.showString(response.charAt(1))

if (response.charAt(1) == ‘Z’) {

let co2_uncompensated = value

co2 = co2_uncompensated + (altitude * 556) / 10000

}

As you can see above, it’s the variable c02 that gets returned by the Co2() function.

The Micro:bit Event System

The BBC micro:bit lets software components talk to each other using event objects. An event is just data which indicates that something in particular has happened and has an associated value or sub-type. Software components can both generate events and indicate that they’re interested in being notified about particular types of event happening elsewhere in the system, when they occur. For example, I might write some code that wants to know when either of the micro:bit’s buttons is pressed. The software component in the micro:bit firmware that is responsible for handling the buttons, known as a driver, generates events whenever buttons get pressed. All my code has to do to receive these events is to register its interest in this type of event using a micro:bit function, and specify what I want to happen when such an event takes place. In the MakeCode programming system, we’re given ready-made blocks for this purpose, such as the onButtonPressed block.

onButtonPressed block code

onButtonPressed block code.

Including the onButtonPressed block in my code, simply means “please tell me if a button gets pressed and execute this code when this happens”.

Events are said to travel along a message bus which you can think of as being like a pipe that events flow along, with some software components injecting event messages into the pipe and others syphoning off copies and processing them.

Technically, events are 32-bit numbers with the first 16 acting as an event identifier (ID) which tells us what type of event it represents and the second 16 acting as a sub-type or an associated value which can be as large as 65535.

Communicating with Bitty Data Logger

Bitty Data Logger uses the micro:bit event system. One of the nice things about the event system is that software components that generate or process events do not have to be inside the micro:bit! They can be connected to the micro:bit over Bluetooth using something called the Event Service. All MakeCode applications which use the Bluetooth package, automatically have the event service built into them, meaning that events can be used for bidirectional communication between the micro:bit and the other device, connected over Bluetooth.

Various event types are used by Bitty Data Logger. These are the ones which were useful in communicating CozIR®-A CO2 sensor data:

Event ID90209030
Event NamePin SelectionData
Direction of Communicationbitty data logger to micro:bitmicro:bit to bitty data logger
PurposeLet’s bitty data logger tell the micro:bit which pins on its edge connector to read data from before transmitting it over Bluetooth.Each 9030 event has a value which combines a pin number with a value. This is how up to three different types/sources of data from an external device, connected to the micro:bit, can be communicated to bitty data logger.
Data FormatBits 0, 1 and 2 are used to select pins 0, 1 and 2 for sampling.

For example:

00000010 means pin 1 should be read.

00000111 means pins 0, 1 and 2 should all be sampled.

Bits 0-9 contain value. Bits 15-14 contain a pin no. So a single event value, indicates both the pin that the data comes from and the data sampled from that pin.

In MakeCode, to be notified whenever the 9020 Pin Selection event is sent over Bluetooth from Bitty Data Logger, and to set some flags indicating which of pins 0, 1 and 2 have been selected in the app, this is all we need to do:

MakeCode application code

MakeCode application code.

To formulate a 9030 data event and send it to the smartphone application over Bluetooth, I usually place the code in a MakeCode function block which I can call from elsewhere, like this:

MakeCode function block

MakeCode function block.

It’s that easy!

Changing the Let’s Talk Science code to work with Bitty Data Logger

To adapt Jennifer’s code to work with Bitty Data Logger, I decided to cheat a little. I decided to pretend that C02 readings were associated with pin 0, temperature readings with pin 1 and humidity readings with pin 2. Of course, all of these readings are being returned over the micro:bit’s pin 1 which is receiving serial data from the sensor’s TX pin, but let’s not quibble. Pretending that the three sensor data types come from different pins, allows us to transmit and classify the three types of data seperately so that Bitty Data Logger can capture and chart the data in the usual way.

Reading data from the sensor is performed in a Forever block and only happens if we’ve accepted a Bluetooth connection, indicated by a variable which gets set when a connection is established or lost, in these event handlers from the MakeCode Bluetooth package:

Accept a Bluetooth connection

Accept a Bluetooth connection.

We then request one or more of the three sensor data types, depending on the pins that were set in the Pin Selection event.

Request co2 sensor data types.

Request sensor data types.

Conclusion

The GSS Carbon Dioxide sensor is great for all sorts of science projects and has great relevance to a range of real world issues. As always, Bitty Data Logger allows phenomena to be visualised and analysed, which is a big help in furthering a deeper understanding.

Give it a try! Bitty Data Logger is in the Apple App Store and Google Play.

http://www.bittysoftware.com/apps/bitty_data_logger.html

Conclusion

The GSS Carbon Dioxide sensor is great for all sorts of science projects and has great relevance to a range of real world issues. As always, Bitty Data Logger allows phenomena to be visualised and analysed, which is a big help in furthering a deeper understanding.

Give it a try!

Bitty Data Logger is in the Apple App Store and Google Play:

http://www.bittysoftware.com/apps/bitty_data_logger.html

Full Solution

https://makecode.microbit.org/_5hEKs3FgR7he

Editor

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Link

https://makecode.microbit.org/_5hEKs3FgR7he

Editor

<div style=”position:relative;height:0;padding-bottom:70%;overflow:hidden;”><iframe style=”position:absolute;top:0;left:0;width:100%;height:100%;” src=”https://makecode.microbit.org/#pub:_5hEKs3FgR7he” frameborder=”0″ sandbox=”allow-popups allow-forms allow-scripts allow-same-origin”></iframe></div>

Contact the author

Martin Woolley | Developer Relations Manager, EMEA at Bluetooth SIG

http://www.bittysoftware.com

https://bittysoftware.blogspot.com/

@bittysoftware 

 

GSS Product Rebrand l Sensor & Test Show

Hall 1, Booth 1-401 Nuremberg, Germany on 26-28 June 2018

Gas Sensing Solutions (GSS) will be launching the rebranding of its award-winning CO2 sensor range on booth 1-401 at the Sensor and Test show in Nuremberg, Germany (26-28 June 2018).

Calum MacGregor, CEO of GSS, explained, “As our range of CO2 sensors increases, we felt it was important to have a very clear branding strategy to make it easy for customers to find the right type of sensor to suit their application. There are now three distinct families that each focus on a particular strength of our technology. The CozIR® family has particularly low power consumption. The SprintIR® family has very fast response times. And the ExplorIR® is for robust applications that brings together the ranges previously known as MinIR and CozIR Wide Range. Within each family there are further sub-brands according to additional features such as ultra-high speed, very low power and wide detection range.”

CO2 Sensors

GSS Range of CO2 Sensors

ExplorIR-W CO2 sensor

ExplorIR-W CO2 Sensor

GSS will have demos on its stand to show these three strengths. The CozIR®-LP shows how a battery-powered CO2 sensor can be used for Demand Control Ventilation. The SprintIR®-6S demo shows how fast the sensor responds to changes in CO2. The ExplorIR® robustness is proven by having it working inside a ball being thrown around the stand.Rapidly growing awareness of the health and safety issues of elevated CO2 is resulting in legislation of permissible CO2 levels. GSS uses its own specially developed LED technology at the heart of its CO2 sensors that dramatically cuts power consumption and speed of response.

This enables CO2 monitors to be designed that, for the first time, can be battery powered with long operational lives. This opens up whole new health and safety application areas such as battery-powered CO2 monitors for offices and factories that cut out the costs of mains cabling. Additional areas include CO2 level monitors for car cabins to ensure driver alertness; wearable alarms for people who might enter high CO2 concentration areas at work such as factories and breweries; and monitoring of CO2 levels in exhaled breath as an indicator of ill health.

Examples of the wide range of applications for GSS CO2 sensors can be found on the company’s website www.gassensing.co.uk

GSS technology

LED Technology

GSS LED Technology

CO2 sensors work by measuring how much light is absorbed by CO2 molecules in the 4.2 and 4.4 microns range as it passes through the sample gases, which is called Non-Dispersive Infra Red (NDIR) absorption. The amount of absorption indicates how much CO2 is present. GSS developed proprietary LEDs that are specifically tuned to emit at these wavelengths. The LEDs use very little power and turn on almost instantly, enabling sensor readings to be made in less than a second. As a result, GSS has pioneered the development of CO2 sensors that can be powered by batteries for long periods of up to ten years. Competitor sensors use IR sources that require significantly more power per measurement and also take much longer to reach a stable condition for a measurement, resulting in the need for mains power.

Gas Sensing Solutions (GSS) www.gassensing.co.uk

GSS is a world leader in CO2 sensor design, manufacture and customisation. Its disruptive technology uses proprietary, mid range, infrared LED sensors to enable best-in-class records for fastest response times, lowest power consumption and longest product lifetime. Based in Scotland, this technology pioneer exports state-of-the-art sensors worldwide, and has in-house bespoke development capabilities to support its international customer base. Tel: +44 1236 781900  sales@gassensing.co.uk

 Media contact:

Nigel Robson, Vortex PR.  nigel@vortexpr.com  +44 1481 233080

CozIR, SprintIR and ExplorIR are registered trademarks of Gas Sensing Solutions Limited.

CO2 Sensor Unveil At AHR EXPO

Responding to market demands for more compact, slimline devices, Gas Sensing Solutions is launching a new CO2 sensor aimed at Building Control, HVAC, IAQ and DCV applications at the forthcoming AHR EXPO running from 30 Jan – 1 February in Las Vegas.

A smaller version of GSS’ current CoZIR®-A, the CoZIR®-LP is the latest generation of this hugely popular product and is fully compatible with the existing device.

CoZIR®-LP’s physical volume is 85% less than the envelope of the current sensor and as with all GSS CO2 sensors it uses SmartIR LED-based technology, allowing for simplified systems and a robust design.

Just like size, power matters, especially for remote “Internet of Things” infrastructure. Operating at a speedy 2 samples/second, the CoZIR®-LP requires a miserly 3mW of sustained power and equally important, a peak pulse current of only 33mA – addressing the major Achilles heel of CO2 sensors in the current-limited environment typical of sensing applications, particularly those which are battery powered.

In fact, the new CoZIR®-LP can be supported by a compact low energy density battery, negating the need for larger batteries and supercapacitors.

Grant Notman, who was recently appointed as Business Development Director at GSS comments;

“With the advent of smart cities and increasing environmental awareness, the monitoring and control of CO2 has become a key green issue. Architects and building managers are now specifying elegant, thin sensor enclosures for consumer/public structures so the CoZIR®-LP, with a height of less than 8mm, provides the ideal CO2 sensor solution.”

Ralph Weir, who took over the role of CEO at GSS in December, adds:

“This new sensor release represents the next node of the evolving GSS leadership CO2 sensor roadmap and offers an ideal upgrade path for space sensitive and evolving battery powered wireless applications. We have a culture of constant innovation at GSS and CoZIR®-LP is effectively “version 3.5”.

“With every iteration, we try to improve every possible facet – this is a far more streamlined design, losing none of the performance whilst adding a greater flexibility for our customers who are seeking ever smaller components. We are hugely looking forward to launching it at AHR Expo this week – you can find GSS at booth C1072.”

AHR Expo, which started 85 years ago as a heating and ventilation show, has grown into the HVACR event of the year and is held in major cities across the U.S.

The 2017 Show will be in Las Vegas, hosting more than 2,000 exhibitors and attracting crowds of 60,000 industry professionals from every state in America and 150 countries worldwide.

It provides a unique forum designed expressly for the HVACR community, allowing professionals to get together to share new products, technologies and ideas.

If you would like to arrange a time to see the new CoZIR®-LP at the AHR Expo in Las Vegas, please get in touch. Alternatively, registration at the show is free until 25th January, so CLICK HERE to claim your free ticket.