How does Air Quality affect our Health?

Air quality can affect a number of parameters in everyday life. From crop yield to water quality and buildings. It has a profound effect on our lives. But how does air quality affect our health? Find out more in our short blog.

There are many reasons to make air quality monitoring a top priority. Research has shown that poor air quality can have a significant effect on our health. It’s been reported by the WHO that nine out of ten people now breathe polluted air, this contributes to the death of around 7 million people each year1.

These alarming figures illustrate the seriousness of the situation and the stark reality that poor air quality is hard to escape.

How does outdoor air quality affect our health?

Outdoor air quality is closely linked to climate change and the effects of our use of fossil fuels.

Cancer Research recently published their findings on how air pollution can cause lung cancer in people who have never smoked2. As part of the TRACERx Lung Study. The programme found that exposure to air pollution promotes the growth of cells carrying cancer-causing mutations in the Lungs. Particulate Matter, particularly PM2.5 (tiny pollutant particles) have been identified as causing inflammation to the lungs which can lead to cancer.

This isn’t the only potential health implication which can arise as a result of outdoor air pollution. Other conditions that can be caused by this include; Chronic Obstructive Pulmonary Disease (COPD), heart disease and Dementia.

While there are lots of contributing factors to outdoor air quality, many of which are outside an individual’s control, monitoring PM levels with low cost LPWAN sensors can be a good place to start assessing outdoor air quality. Through careful monitoring, information recorded by deployed sensors can be used to identify trends and build up data to allow you to make more informed decisions as to how you can improve outdoor air quality. In order to maximise your project’s effectiveness, it is essential for data to be monitored before and after measures are put in place.

How does indoor air quality affect our health?

Indoor air quality on the other hand is more within our own control. We’ve outlined some potential implications which can come as a result of poor indoor air quality.

Mould & Dampness

Not only is mould unsightly, it can also cause harm to your health. Following the tragic news of the death of 2 year old Awaab Ishak, the implications of mould exposure are sadly very real.

The increased cost of energy is likely to increase the risk of mould inside buildings too. With cold weather comes condensation. Ordinarily putting the heating on would help to dry out the air indoors, but with significant rises to the cost of energy, more and more people are turning their backs on their thermostat.

The most common causes of mould are:

  • Humidity
  • Condensation
  • Rising damp
  • Poor ventilation

Caused by excess moisture, moulds emit spores which can cause a variety of health issues. For babies, young children and those with underlying health conditions including allergies or respiratory conditions such as asthma, these spores can be even more harmful. Monitoring indoor air quality is a simple, yet effective way to alert Landlords, Housing Associations and homeowners of high moisture/humidity levels which can be used to identify the dew point and the need for ventilation.

How does air quality affect our health in the office and schools?

The WELL building standard has helped to transform health and wellbeing in buildings. It’s estimated we spend around 90% of our time in enclosed spaces. During this time, we inhale pollutants which can be detrimental to our health and wellbeing. Elements such as Volatile Organic Compounds (VOCs), Carbon Dioxide, Carbon Monoxide and Nitrogen Dioxide can all contribute to the overall indoor air quality.

We recently completed a project installing CO2 sensors throughout schools in Scotland. There have been numerous studies over the years about the effect CO2 levels has on our cognitivie performance. Read more about how using LoRaWAN® technology has helped to transform the overall performance and wellbeing in the classroom.

Why use IoT to monitor air quality?

LPWAN devices are ideal for monitoring air quality. With a long battery life of 5+ years, once deployed you can access recorded data from wherever you may be. Devices can be configured to your parameters. If readings fall outside of your set parameters an automated alert will be triggered from your software platform to notify you that an action needs to be taken i.e. open a window to improve ventilation. Data recorded by deployed devices can also be used as evidence of regulation compliance.

How can Alliot help?

While the impact of air quality can be serious for our health, IoT devices can be used to minimise the long-term effects and empower us with more intelligent data to make better decisions. Alliot offer a wide variety of indoor and outdoor air quality sensors and associated software. Whatever parameters you are looking to monitor, we can help you deliver projects of all sizes and locations. Whether you’re looking to monitor indoor air quality conditions in Social Housing across the country or optimise your office environments to improve staff wellbeing and productivity, our expert team are here to help. Contact us today to discuss your air quality monitoring requirements.

1 World Health Organisation 2018, How air pollution is detroying our health, accessed 30th November 2022, <https://www.who.int/news-room/spotlight/how-air-pollution-is-destroying-our-health>

2 Cancer Research UK 2022, Scientists reveal how air pollution can cause lung cancer in people who have never smoked, accessed 30th November 2022, <https://news.cancerresearchuk.org/2022/09/10/scientists-reveal-how-air-pollution-can-cause-lung-cancer-in-people-who-have-never-smoked/>

IoT Connectivity: What are the options?

IoT Connectivity: What are the Options?

When it comes to selecting your preferred IoT connectivity there are a number of things you may want to consider. To help simplify this process, we’ve compiled a short guide to outline the options available and our top tips to think about when selecting the best option for your solutions.

There are numerous ways to connect your IoT devices, some will require a SIM card whereas others will require a gateway, or even connect to a satellite! The type of IoT connectivity you select is critical to the success of your IoT project and each option comes with its own range of benefits. The key here is to really understand what your requirements are and if your chosen connectivity will support your objectives.

What options are out there?

Here at Alliot we specialise in two key technologies: LoRaWAN® and NB-IoT/LTE-M (cellular IoT connectivity). But there are other options out there, these include:

Wired Connections

Wired connections were among the first methods of connectivity used in the early days of IoT. This tends to work well for items that will remain in a fixed position, but there’s little flexibility and there are much more efficient options now available.

WiFi

We’ve all become well accustomed to connecting our devices via WiFi and it often works well for simple home applications. WiFi however is notorious for its limitations with regards to range. Using WiFi for your IoT connectivity would require lots of access points to ensure its reach and it will also eat up a lot of battery power. Battery life is incredibly important when it comes to IoT sensors, especially if you’re installing solutions across multiple sites – replacing all those batteries would prove very time consuming!

Satellite

If you’re looking to monitor parameters in the middle of the ocean, satellite connectivity is the best option. There are geostationary satellites in orbit connecting devices around the world. It’s also reported that low earth orbit satellites are on the cards for companies such as SpaceX.

What options do Alliot Offer when it comes to IoT Connectivity?

LPWAN

Now this is our bread and butter! Low power Wide Area Networks were specifically designed for IoT use. LoRaWAN® devices offer long battery life by periodically transmitting small packets of data to a connected gateway. These gateways then connect to a LoRaWAN® network which offer a long range of up to 10km (depending on location) and don’t interfere with any existing networks or infrastructure.

Cellular Connectivity

Cellular IoT such as Narrowband IoT (NB-IoT) and LTE-M offer a great alternative to LoRaWAN®. NB-IoT is the newest kid on the block when it comes to IoT connectivity. Like LoRaWAN®, it offers an excellent coverage range and supports a long battery life.

However, unlike WiFi or LPWAN solutions using ethernet powered gateways, cellular doesn’t require an ethernet connection. Connectivity is instead supported by piggybacking on mobile networks. These devices require the use of a cellular IoT SIM card.

The main difference between NB-IoT and LTE-M is the support of mobility on the network. If you’re looking to track assets across multiple locations for example, LTE-M is likely to be the best option for you as it is better suited to faster moving assets that you need more frequent messages from as it supports handover.

Things to Consider…

There are a few things we’d recommend you take into consideration when selecting the type of IoT connectivity for your solutions.

Coverage

We’ve all experienced the loss of phone signal in remote locations. Sometimes cellular coverage can be weaker or unavailable in certain areas. Before going full steam ahead with a cellular IoT solution, it’s important to check the coverage available; we can help you with this.

In some areas, LoRaWAN® could well be the better option for you as you have the ability to create your own network therefore enabling you to ensure a relatively stable coverage across all types of locations. With LoRaWAN® you have the flexibility to create your own coverage by installing gateways, there are no licensing costs for the radio, and you can install them anywhere you want!

Cost & Scalability

Both LoRaWAN® and cellular IoT are future-proof in terms of scalability. With NB-IoT and LTE-M you have the ongoing cost of your SIM cards. The cost of SIM connectivity is low and given the size of your solution can be very cost-effective when compared to the costs involved with setting up a LoRaWAN® solution. Cellular IoT is great option where you only want a very small number of sensors per site, since you don’t need anything other than the sensor and a SIM contract which costs pence per month, per device. In these instances, installing gateways would be prohibitively expensive for a small number of sensors. Plus, you have the added benefit that the network is the responsibility of the mobile network provider!

If, however your solution is going to have thousands of connected devices, LoRaWAN® could prove to be more cost-effective for you as it operates on free (unlicensed) frequencies which you manage yourself so there are no upfront licensing costs to use the technology and you can potentially connect thousands of sensors to one gateway.

Deployment

Both NB-IoT and LoRaWAN® solutions are simple to install. We can even ship devices to you ready to plug & play! LoRaWAN® gateways offer coverage between 10km and 2km based on the installation environment. This is ideal for monitoring sensors deployed within this distance. However, if you’re looking to track assets throughout the country for example, LTE-M may offer a better alternative.

Whatever your requirements we’re here to help. Both cellular IoT and LoRaWAN® offer excellent options when it comes to connecting your IoT solutions. Get in touch today to discuss your IoT connectivity.

Our experts are on hand to help you every step of the way
Lets talk

Join Alliot at The Things Conference 2021

With just under two weeks to go until the world’s largest LoRaWAN event goes live, we’ve been taking a look at what the event has to offer. Find out why we think The Things Conference 2021 is this year’s must attend event.

Having sponsored The Things Conference in Amsterdam last year, we were incredibly impressed with the quality of the content provided throughout the event. We won’t be jumping on a place to Amsterdam this year unfortunately, but with a new virtual approach it’s expected the event will attract over 15,000 IoT professionals from around the world! Taking place from 25th – 29th January 2021, this year’s Things Conference is set to be a great event jam packed with the latest news, products and tech developments.

Top 5 Reasons to Attend The Things Conference 2021

  1. Hear from some of the world’s leading experts about the truth behind creating LoRaWAN solutions. Discover what can cause the biggest headaches, and how to avoid the biggest pitfalls.

  2. The Things Conference 2021 is a content-led event, aiming to provide insightful, educational information to inspire its attendees. All attendees can access a wide variety of workshops, presentations and demos to help you to develop your LoRaWAN knowledge. Our very own Technical Director, Paul Hayes will be hosting a workshop on what to look for when choosing your LoRaWAN devices. Join him on Monday 25th January at 3:45 pm to hear more.

    The full conference schedule can be viewed on The Things Conference 2021 website.


  3. Discover the latest LoRaWAN products on The Things Conference 2021 Wall of Fame. Featuring the latest and greatest IoT hardware, the virtual Wall of Fame provides all the vital information you need to know about the newest LoRaWAN products.

  4. The Internet of Things Podcaster, Stacey Higginbotham will be hosting a series of interviews throughout the conference. Tune in to hear our Business Development Manager, Robert Ferriday’s top tips for ensuring practical LoRaWAN deployments.

  5. Connecting with others in the industry can be difficult under the current COVID-19 restrictions. With curated matchmaking and online networking areas, you can be sure you’ll be connected to the people most suited to your requirements. It’s also a great opportunity to join small groups to discuss specific LoRaWAN topics with like-minded individuals.

Registration couldn’t be easier, simply register online today to start planning your schedule for The Things Conference 2021. For a 20% discount on your ticket price enter our discount code: TTC2021-FRIEND-OF-ALLIOT at the checkout.

We hope you’ll be able to join us! To schedule a meeting with a member of our team please get in touch.

How can IoT help with Ventilation in the Workplace?

Ventilation in the workplace with Alliot Technologies

Ventilation has long been a requirement in the workplace. Now, as we head into winter ventilation is more important than ever in helping to create a COVID-secure workplace. We’ve taken a look at the latest guidance and how LoRaWAN air quality sensors could help.

It’s outlined by the HSE that all workplaces need an adequate supply of fresh air. This is often achieved naturally from doors and windows, or can be controlled through HVAC systems. But, as we enter into the colder months, having windows and doors open is not always practical (least not in the UK!). What’s more, with the added complication of COVID-19, there’s now even more reason to ensure air flow rates are maintained at the recommended rate.

The WHO has reported that HVAC systems can both positively and negatively affect the risk of pathogen spread. Re-circulation of air is not recommended. If air is being circulated, it is recommended that filters are cleaned regularly. This is where IoT can come in.

Meet the enLink Status-AF

Monitor ventilation in the workplace with the enLink Status-AF

The enLink Status-AF LoRaWAN air flow sensor is specially designed to monitor and ensure recommended air flow rates. It can be easily installed into the area you wish to monitor, with no interference to any existing equipment you may have running. Recorded data is then transmitted to your chosen dashboard via a LoRaWAN gateway. Alerts can be pre-configured to be automatically raised if ari flow rates are outside of your set parameters, enabling you to take quick action if it’s required.

Protection Against Your Investment

Despite its importance right now, ventilation in the workplace is here to stay. Using IoT in monitoring your air flow rates can help to create a COVID-secure workplace, but it can also be useful to:

The Things Conference: Will You Virtually Be There?

Given the current climate, much of the world is now under strict social distancing measures and being asked to #stayhome. This has seen many industry events be postponed for the foreseeable future. Thanks to our friends at The Things Network and the fantastic tech available they will be bringing the IoT industry together on 16th April for a worldwide virtual conference which we’re delighted to be supporting!

The Things Virtual Conference - Register Now

What to expect from The Things Virtual Conference

Boasting 24 hours worth of online content, The Things Virtual Conference is a great platform for connecting with tens of thousands of LoRaWAN® professionals from across the globe. With a variety of virtual IoT conference rooms, attendees will be able to engage with industry experts while accessing premium content at the click of a button.

Over the course of the day, attendees will be able to:

  • Interact with IoT industry experts
  • Participate in hands-on workshops about Edge Computing, hardware secure elements, The Things Stack, battery optimisation, gateway configuration, cloud integrations and much more
  • Listen to panel discussions featuring top-notch technology providers
  • Hear more about LoRaWAN® deployments in the wild

…. and much more!

What will Alliot bring to the The Things Virtual Conference?

Our Technical Director, Paul Hayes will be presenting on the Mass Deployment of LoRaWAN® Sensors. Having developed our own set of provisioning services, in his session, Paul will be looking at the current state of play and what the future holds with regards to growing the LoRaWAN market.

Get Your Ticket

Registration for The Things Virtual Conference couldn’t be easier, simply register your details to secure your ticket!

Sit back, stay home and join us on 16th April for what’s set to be an incredible day for IoT.

Achieving long battery life with LoRa sensors

LoRaWAN technology is known for its long range and low power usage.  In fact, LoRa stands for “Long-Range”. There are certain ways to optimise the battery life of LoRa sensors. This blog post covers key technical factors that will help to improve LoRa battery life.

LoRa is a radio communication technology that LoRaWAN uses for transmission of messages. It can be thought of as the physical layer in the OSI Network Stack.

The exact details of LoRa modulation are proprietary and the property of Semtech Corporation but it uses a technique called chirp spread spectrum to travel long (multiple kilometer) distances with relatively low transmission power.  By comparison, other modulation technologies such as frequency shift keying (FSK) would either cover much shorter distances or require much higher transmission power.

Despite all this, a device running off a small, cheap battery will only last months or years by spending the vast majority of it’s time powered down.

Some of this is down to the manufacturer of the devices you are using, they need to have done a good job of designing their device and writing the software for it so that it goes into as low a power state as possible  when it is not doing anything.

The rest is down to the data being sent and the radio signal strength between the device and the nearest gateway.  The data format might be fixed by the device manufacturer, or you might be able to design this yourself.

Optimising LoRa Battery Life

  • Send small amounts of data:

The smaller the data payload the device is sending, the less time the device needs to be powered up.  Even with the low power usage LoRa gives you, transmitting data uses power.

Most LoRa sensor devices will have a LoRa radio chip and a separate micro-controller which both use power.  The less data being sent, the less time it takes to send so the less power is used.

Data is sent in bytes and you want to send the minimum amount possible to maximise LoRa battery life.  You can achieve this by being a bit clever about how you encode your data.  As an example, lets say you have a sensor reading ambient temperature, here are some ways you could encode that data:

“Temperature: 21.26” as text encoded into ASCII ends up as 54656d70657261747572653a2032312e3236 which is 18 bytes long.

If you shorten this to “2126” and then convert to a readable format in your application, this data in ASCII hexadecimal is 32313236 which is 4 bytes long so less than a quarter.

If you actually convert the number 2126 to hexadecimal you get 084e.  So now only 2 bytes.

You should always avoid sending text.

  • Send messages less frequently:

If you send messages less frequently, the device is in it’s low power sleeping mode for a longer percentage of time so the battery will naturally last longer.  As tempting as it can be to make your sensor send data back every minute or so, it’s hardly ever necessary.

For example, a sensor taking readings of soil moisture to control an irrigation system.  Soil moisture isn’t going to change rapidly, taking a reading once every hour will most likely be suitable, taking a reading every five minutes is a waste of energy.  Potentially your battery will last 12 times as long which could be the difference between changing it every 2 months or every 2 years.  This is an over-simplification but useful enough for this example.

Even for things like temperature, humidity or CO2 metering inside buildings, these factors only significantly change over the course of hours rather than minutes so having per-minute accuracy isn’t necessary.  Something like every 15 minutes would be ample to increase LoRa battery life.

  • Keep LoRa Spreading Factor as low as possible:

The spreading factor in LoRa relates to the length of the “chirps” sent over the air when transmitting data.  Longer “chirps” (which equate to a higher spreading factor) take a longer amount of time to transmit but will be successfully received over a longer distance.  Spreading factor numbers go from 7 to 12, for each step up the transmit time doubles.

This screenshot is taken from The Things Network console showing several LoRa messages received by a gateway using various spreading factors:

Note the column headed data rate and the values given for “SF”.  Then note the corresponding values under the air time headed column.  You’ll see several messages at SF7 with an air time of around 40-60 milliseconds depending on the size of the data.  There is one message at SF9 with an air time of over 164mS and lastly one message at SF12 (the highest factor) which has an air time of 1482mS, or nearly one and a half seconds! That’s about 25 times the amount of time needed to send the same message at SF7.

It’s clear that higher spreading factors will have a huge effect on battery life, potentially 25 times less if using SF12 in comparison to SF7 in this example (which is showing some real data).

So you want to use the lowest spreading factor as possible.  LoRaWAN does this using an “adaptive data rate” mechanism.  Exactly how it works is dependant on implementation of the network server.  But for example (at the time of writing this), The Things Network’s server will wait until it has received 20 messages from a device, then if the signal strength is very good, it will instruct the device to reduce it’s SF.  There is an acknowledgement mechanism used after this to allow a device to ensure it’s data is still received.

For more information on how ADR works with TheThingsNetwork, see this page.

This screenshot from the ThingsNetwork console shows ADR in action:

lora battery life

Here you can see the network server adding commands to a downlink message to tell the device to change it’s data rate (where you see “link-adr” in the screenshot).

Using lower spreading factors relies on network coverage.  Using higher factors will allow messages to travel further and still be received when interfering factors are in play such as buildings between the device and the gateway.

Ultimately you might only be able to use lower spreading factors by adding more gateways to your network but at least this is possible with LoRa. Unlike for example if you have a poor mobile phone signal then your only real option is to move somewhere else with better signal.

For more information about how the technical team at Alliot can help you to achieve your business goals using LoRaWAN devices, get in touch today.

LorixOne LoRaWAN Gateway – What Does It Do?

At it’s most basic level, any LoRaWAN gateway’s job is to receive messages from sensors over radio signals and forward these to a LoRaWAN network server.  The network server then decides what to do with these messages – more than likely store the data from them so someone or something can analyse them later on.

The gateway needs to be programmed to talk to your LoRaWAN network server, whether that’s something like The Things Network, Loriot or your own server (the LorixOne supports all of these systems), the gateway talks to a Network Server over an IP connection.

The LorixOne gateway has a single RJ45 connection to plug into a network.  It comes with a passive-PoE adaptor which is used to provide both an IP connection and power down a single Ethernet cable to the gateway.  It doesn’t support 802.3af/802.3at Power-over-Ethernet standards, so you need to use the passive-PoE injector supplied even if you already have a PoE capable network switch.

It doesn’t matter how the gateway reaches the Network Server as long as it can.  So you can simply connect it up to your IP network, or you can connect it to a converter such as a 3G/4G router or a Wifi bridge for back-haul to the LoRaWAN network server.   Just how much bandwidth is required will depend on how many sensors will talk via this gateway and how often they will talk.  However, LoRaWAN uses minuscule amounts of data, each message being a few bytes in size only.  Just looking at the console in my own ThingNetwork account at the last few messages my LorixOne gateway received, I can see that two of them were 14 bytes and one of them was 20 bytes.

So doing some pretty crude estimations as an example, lets say we have 100 sensors sending messages every ten minutes (which is actually quite a lot for most use cases) and the average message size is 16 bytes.  UDP & IP overhead adds about 30 bytes (more for IPv6, TTN seems to be IPv4 only at the moment).  So lets say that each message uses 46 bytes on the wire, it could be more depending on how your gateway is talking to the network but this probably isn’t a million miles off:

  • In one hour, one sensor will send 276 bytes (46×6)
  • In one hour, all 100 sensors will send 27.6 kilobytes (276×100/1000)
  • In one month (lets just say 30 days), we will require 19.87 megabytes (30 days is 720 hours, 720×27.6bytes / 1000 to get MB)

Even if you had 10,000 sensors doing this you’re using less than 2GB a month.

Radio Capabilities

The LoRa radio in the LorixOne gateway is based on the Semtech SX1301 chip.  This is an 8-channel radio which means the gateway can receive 8 messages from sensors at once.  How many sensors it can handle is hard to answer as it depends on many factors.  These include: how often the sensors are sending messages, how much data the messages contain and the signal strength between sensors and the gateway.  Sensors that have a weaker signal will increase their transmit time in order to send data, this means a receive channel on the gateway is tied up for longer.

When it comes to sending data from the gateway back to sensors, there is only a single channel for this.  In addition, the regulations for use of ISM band radio devices states that you can only send data for 5% of the time (depending on exactly which channel is being used though) in Europe.

LoRaWAN (in common with many other low power wide area networks) is asynchronous, it’s not quite one way only but it’s not far off.  If you are wanting to send data back to your sensors, you need to be careful how you manage this and ensure you don’t break the regulations.

The gateway should easily be able to handle several thousand sensors sending small pieces of data periodically.

Software and Configuration

The LorixOne gateway is an embedded computer running a Linux based operating system (based on Yocto).

Configuration is done by command line only, you need to ssh in to it.  Use the ‘ssh’ command on a Mac or Linux PC, download the Putty program on Windows.

We can help with configuration and can pre-configure gateways before shipping them.

Get in touch if you are interested in this (contact@alliot.uk)

Gateway Variants

There are two product codes you can order for the LorixOne gateway.

LORIXONEIP65O: this is the outdoor IP67 rated version of the gateway

LORIXONEIP43I: this is the indoor IP43 rated version of the gateway

In reality the only difference is the antenna which is supplied with the unit.

The outdoor version contains a fixed position 500mm 4.15dBi antenna.  This will give the longest range, the gateway needs to be installed vertically.

The indoor version contains a variable position (as in the angle of it can be adjusted so the gateway can be installed horizontally or vertically), 200mm 2dBi antenna.

Both are currently the same price.

Verdict

Things I like about this gateway are:

  • it’s really small!  The body of the unit is a cylinder of approximately 200mmx45mm diameter.  This helps make it easy to install without looking messy
  • Very easy to mount.  Just strap it to a pole
  • Outdoor rated.  IP67 dust/water ingress rating means it can be sited wherever you want
  • The price.  We have retail and trade pricing.  For an IP67 gateway, I haven’t found anything cheaper
  • Quality.  The gateway looks & feels very high quality, it’s made of tough ABS plastic, it feels like it will last a long time.  The software is running off NAND flash, not an SD card or similar

Limitations:

  • passive PoE instead of 802.3af/at.  I think it’s a shame it needs an injector and power supply, although both are included in the box
  • Ethernet only.  I would like to see versions that include an integrated 3G/4G modem and a SIM card slot, perhaps a wifi version too.  I wouldn’t want a single gateway with them all, it will become too expensive.  You can of course connect it to a 3G/4G router or Wifi bridge

Given the price and that those limitations are either not much of an issue or easily solvable, this gateway is just about the best thing I’ve seen so far for building a LoRaWAN network.

LoRaWAN DIY Sensor

If you’ve got a LoRaWAN gateway, or are in range of an open gateway such as  The Things Network, you’ll need some sensors to start collecting data. Find out how Paul (our head technical advisor) made his own DIY LoRaWAN sensor using a Lora32u4 board. 

We will be supplying commercial sensors but for experimentation (and because it’s fun) I made my own.

In keeping with the design goals of LoRaWAN, I wanted the following features:

  • low cost
  • able to run off a small battery for at least a month (ideally much longer)
  • easy to program without having to purchase device specific programming tools, ideally an Arduino compatible board
  • capable of monitoring temperature and humidity with a reasonable level of accuracy
  • data collected by The Things Network

I’ve done lots with Arduino boards over the years so using something compatible with that made a lot of sense to get something working quickly.

I wanted to make four different DIY LoRaWAN sensors.

After a small amount of research, I found the Adafruit Lora32u4 board and then the BSFrance clone of this.  The BSFrance version of this is the cheapest board I’ve come across that incorporates a Lora radio with an Arduino MCU.  It also includes a battery connector and a LiPo charging circuit so is easy to run from a small battery.

This board consists of an RFM95 LoRa chip connected to an ATmega32u4 microcontroller.  These two components talk to each other using a protocol called Serial-Peripheral-Interface.

Then I searched for a combined temperature and humidity sensor device.  I usually prefer using digital devices than analogue devices such as thermistors as I feel the manufacturer will have already done the hard work of converting the analogue readings into a usable value and will have done some calibration.  In my experience, these devices give a more accurate reading with less effort.

I decided on a Honeywell HIH6130 chip (which I found on Farnell).  It uses a protocol called i2c, this is a simple serial protocol which is widely supported by many embedded systems, including Arduino.

To power my DIY LoRaWAN sensor, I needed batteries. The Lora32u4 board includes a Lipo charging circuit so I decided on using small LiPo batteries, the sort designed for small quadcopters/drones.  I went for 600mAh batteries as they were very cheap!  One thing I found is that the polarity of the connector was incorrect for the BSFrance board, so I had to remove the pins from the plastic housing and connect them the other way round.  Be very careful, incorrect polarity and short circuits of Lipo batteries can cause fires and explosions.

So next, I got the HIH6130 datasheet, BSFrance Lora32u4 pinout diagram and a piece of paper to design the circuit for my LoRaWAN DIY sensor.  As this is an experiment only, I designed it with a view to mounting on stripboard/veroboard.  I ended up with this:

DIY lorawan sensor using Lora32u4 board

You may note that it shows a GPS module connected to the serial port of the Lora32u4 board.  This was just another experiment I did with logging co-ordinates to The Things Network.

The next step is to translate this to a breadboard (prototyping board).  Before that though, I had to figure out a way of mounting the HIH6130 as it is a surface-mount chip and so wont fit into either a breadboard or the stripboard I wanted to eventually use.  I found these adaptor boards on Farnell.  Expensive for what they are but solve a problem easily.  Soldering the HIH6130 chips to these was fiddly, my tip is to use a small piece of Blu-Tac to hold the chip in place while you get the first couple of pins soldered.

I prototyped two sensors side by side on breadboard, the left hand one also includes a connection to a GPS board (which I already had lying around in a drawer):

prototype DIY lorawan sensor using lora32u4 board

That’s the hardware largely sorted for my DIY LoRaWAN sensor. Next is to write some software to make it do something.  There’s lots of ways of writing, compiling & uploading code for Arduino compatible systems.  In this instance I used a text editor/IDE called Atom with a plugin called PlatformIO, I used these because I specifically wanted to try them out.

Using the PlatformIO Atom plugin, it’s really easy to search for and install Arduino libraries.  One of the advantages with Arduino is it’s popularity and amount of high quality libraries that exist for it.  For this project I used:

  • LMIC-Arduino: an implementation of the LoRaWAN protocol in C, ported to Arduino
  • Low-Power: a simple way of making Arduino boards go to sleep and then wake up after a specific amount of time or in reaction to an interrupt
  • SPI: needed for communication with the RFM95 LoRa radio chip
  • Wire: this is part of the standard Arduino system (so doesn’t need installing separately).  It allows you to talk to I2C devices.  I did find a library specifically for HIH61xx chips, I can’t remember why I didn’t use it, I think it was because I found it just as easy to directly use the Wire library.

My program operates as follows:

  • when the sensor starts up, it joins the LoRaWAN network using a device ID and application key.  Using Over-The-Air-Activation process.
  • then it enters a never ending loop:
    • re-join if necessary
    • read temperature & humidity from the I2C device
    • read the battery voltage level from an analogue pin on the Lora32u4 board (the BSFrance board allows you to get the battery voltage)
    • send data to the Lora chip
    • go into low power sleep mode for ten minutes

Aside from the obvious task of actually sending readings to the LoRaWAN network from the sensor, there’s a couple of really important things it does.

One is to go into sleep mode, the device will spend the vast majority of it’s time in low-power sleep mode.  This is what gives a sensor the ability to last a long time on a relatively small battery. Without this it will not last very long at all.  If you are making a battery-powered LoRaWAN DIY sensor then you want to make sure that is it spending most of it’s time asleep and that any unused peripherals on your microcontroller board are switched off.

The next is using OTAA and rejoining the network if needed.  In LoRaWAN, a pair of security keys are used.  Using OTAA these keys are generated during the join process and are not hard-coded into your sensor.  The less secure method is using Activation By Personalisation (i.e. hard coding the keys into your device).  This is not secure and should be avoided.  When using OTAA it’s important for a device to re-join (and get new keys generated) if needs be (and it’s recommended to do this periodically anyway).

programming lorawan diy sensor using otaa

I uploaded this code to each of my four DIY sensors (each one contains it’s own ID and application key) and they were happily sending data to The Things Network every ten minutes:

the things network screenshot diy lorawan sensor

The last step for now was to put my DIY LoRaWAN sensors onto stripboard instead of breadboard so they are permanent circuits.  I wanted to make the finished article as small as possible.  There’s various pieces of software you can use for such things, I personally prefer just using paper and a pencil.  You can download templates for printing off which have stripboard layout printed on them.

I usually end up drawing a few versions because once you have the first version you often see a way of making it smaller or simpler.  At the end of this process, my finished DIY LoRaWAN sensor looked like this:

The small white wire on the Lora32u4 board connects the DIO1 pin to digital pin 6.  This is needed when using the LMIC library (and possibly others, I don’t really know why the board comes without this as standard).  I think newer versions of the Lora32u4 board have a simpler way of doing this.

Conclusion

After making these DIY LoRaWAN sensors, I went on to program a simple dashboard that graphs the sensor readings, I will write another blog post on this later on.

I’ve had my sensors running for about six months now, I’ve had no issues.  I have found that the batteries last approximately two months before they need re-charging.  I was hoping for a longer life than that but I am using very small 600mAh batteries, they are also very cheap from eBay and I have my doubts as to whether they really have this capacity.

I haven’t done any range tests, they certainly work anywhere in our building though.

This was a fun experiment and I have learnt a lot about how sensors work and are made, this is obviously way off a finished product and I have no intention of making it into one.

My experience tells me that if you want a sensor, always try to purchase an off the shelf device if you can.  Making your own DIY LoRaWAN hardware gets more costly and time consuming than you can imagine.

Building a LoRaWAN gateway

Our in-house LoRaWAN technical expert, Paul, decided to build his own LoRaWAN DIY gateway. Find out how he did it in this blog post.

If you want to experiment with LoRaWAN and aren’t lucky enough to live somewhere already covered by an existing The Things Network gateway, you’ll need to buy or make your own LoRa gateway.

When I initially started my own testing of LoRaWAN technology I built a DIY LoRaWAN gateway.

The finished gateway

Hardware build

Having already read a few guides and blog posts on building a DIY LoRaWAN gateway using a Raspberry Pi as the controller, I figured this was the best way to go.  I’ve been using Raspberry Pis for experimentation for years, have loads of them at my disposal in the office and know how to use them.

My requirements were something that is a nice self-contained box that can sit in our office and look reasonably good as opposed to a pile of circuit boards on a test bench.  I wanted to connect it directly to Ethernet and power the whole thing using Power over Ethernet (PoE) instead of a separate power supply. 

My DIY LoRaWAN gateway is for indoor use only, just to keep things simple for the housing.

First, I collected the following parts:

  • Raspberry Pi version 3
  • 4GB MicroSD card for the above.  I recommend buying Noobs cards because they are known to work well and SD cards are a bit of a weakness of the R-Pi
  • IMST iC880A SPI LoRaWAN concentrator board
  • iC880A backplane.  Various ones are available, I used the Coredump one (some basic soldering required or order it fully assembled)
  • u.fl to SMA – Pigtail cable for iC880A-SPI from IMST
  • 868MHz antenna from IMST
  • (note: the above two items are available from various places but I ordered them along with the concentrator board from IMST)
  • TP-Link TL-POE10R PoE splitter.  From Amazon.
  • Plastic project box from Farnell.  Part code: 2478793
  • Panel mount Ethernet coupler from Farnell.  Part code: 2708703
  • 2mm thick ABS (plastic) sheet (for mounting all the components to and fitting inside the project box).  From Ebay.
  • 2.1mm barrel connector with twin wire (cut this off an old dead power supply)

I already had various Ethernet cables and tools.  Not many tools are needed, a small drill with a selection of drill bits, selection of screwdrivers, sharp knife (Stanley knife or art knife) for cutting the ABS sheet, some cable ties.

You will also need a method of writing to an SD card, either a USB card reader or a card reader built into your PC/laptop.

Putting it all together

I think a picture speaks a thousand words here so this is a picture showing the internal parts inside my DIY LoRa gateway:

concentrator board inside diy lorawan gateway

  • The Coredump backplane comes with plastic standoffs which sit on the Raspberry Pi mounting holes, these are screwed through the 2mm plastic backing sheet I cut down to size to fit the mounting holes in the project box.
  • The backplane plugs into the Raspberry Pi board and the IMST LoRaWAN concentrator plugs into the backplane.
  • The backplane provides power to both the IMST concentrator board and the R-Pi.  It has a voltage regulator accepting anything from 6.7v to 28v DC input.  So the output from the PoE splitter into connected to this with the splitter set to either 9v or 12v.  This is the only power input needed.
  • In the picture, the purple Ethernet cable is the network+PoE input, the black Ethernet cable is the network connection from the splitter into the R-Pi.

Software configuration

  • Download the latest Raspbian lite/minimal image.  At the time of writing, this was based on Debian Stretch.
  • Burn this on to your SD card.  Even if you bought a Noobs SD card I would still over-write the operating system that comes pre-installed because it includes a lot of software you don’t need, including a full desktop environment.  There are loads of how-to guides on how to do this already so I’m not going to repeat them here.
  • Put the SD card into the R-Pi and then power everything up.
  • SSH into the R-Pi (default login is username ‘pi’, password ‘raspberry’, please change this to something else immediately!).
  • The R-Pi talks to the IMST board over SPI (serial peripheral interface), this needs to be enabled:
    sudo raspi-config
    Select “Interfacing Options”
    Select “SPI”
  • Assuming you want to use The Things Network, there is an installer script available on Github. Install steps:
    sudo apt update
    sudo apt install git sudo
    sudo adduser ttn
    sudo adduser ttn sudo
    sudo visudo
  • add the line:
    ttn ALL=(ALL) NOPASSWD: ALL
  • save and close that file, then install the software:
    git clone -b spi https://github.com/ttn-zh/ic880a-gateway.git ~/ic880a-gateway
    cd ~/ic880a-gateway
    sudo ./install.sh spi
    and follow the instructions. I didn’t bother with the remote management things
  • During installation, it will tell you that gateway’s EUI, you will need this to add the gateway to The Things Network so make note of it.
DIY gateway

Connecting to The Things Network

The Things Network have excellent documentation already so I’ve leave this part largely for the reader to work out.  If you’ve managed the above steps then this will be straight forward.

One thing to note is that you need to select “Legacy Packet Forwarder” when adding the gateway in the TTN Console.  Once you’ve done this you should soon see the status to go “connected” with a green icon, this means you’re ready to go!

diy lora gateway in ttn console
DIY gateway in the TTN Console

Conclusion

This is a fairly quick, relatively cheap way of getting a fully capable LoRaWAN gateway up and running.  I would consider it suitable for experimentation & hobby purposes.

Whilst I’ve found in the past that Raspberry Pis will trash their SD cards from time to time, my gateway has been running mostly non-stop for about 8 months now without any issues.  I’ve only powered it down once or twice though to move it to a different location in our office.

The total cost will be about £250.  Commercial, off the shelf LoRaWAN gateways are now getting down to that price.  The LorixOne gateway we sell for example, isn’t too far off now:

LORIX One LoRaWAN Gateway