Solar Charging Improvements

Posted on September 2, 2017 by Ray Keefe

Powering Telemetry

A big issue in the world of the Internet of Things, or IoT as it is abbreviated, is how to get power to remote devices. And this splits up into two separate but definitely related problems:

the power source
the power consumption

Obviously, if the power consumption is high, the power source has to be capable of providing a lot more power. We looked at this in our IoT – Remote Telemetry Case Study. So let’s tackle that one first.

And the focus for this article is remote devices using Solar Charging. Before we look at that specifically, let’s understand the problem.

Power Consumption

There are multiple ways to reduce power consumption. These were covered already in Reducing Power Consumption and Reduce Power While Awake with examples given in Sleep Saves Energy.

Low Power Sleep Mode

The short version of this is that you have to do two things at the same time:

reduce the average power that is consumed all the time
reduce the energy required to process an event

The first of these is also known as Quiescent Power Consumption. This is the power consumed just running the system when it is doing nothing, or close to it. At a minimum, the Power Supply has to deliver this amount of power just to make sure that we could react to an event, should it occur. And I can hear you thinking that it is hard to get this low enough and still have a responsive system.

Correct! But you have to have at least this amount of power or Game Over!

Which is where the second part comes in. You also need some power to respond to events. These can be something you need to log, or reports you need to post. If you are uploading to a web service using cellular communications, the peak power consumption can be very high. So you have to minimise this time.

We would normally model both of these and work out a power budget based on the worst case scenario model. Excel is a suitable tool for doing simple modelling of this as well as scenario modelling.

But I can hear you thinking “why worst case“? Answer: “Because you want it to always work, not just work on average“!

Telemetry

Telemetry means measurement at a distance or remote measurement. So you are measuring something at location A, and want to know the value of the measurement at location B. This implies the two locations are not close enough together that this is a trivial problem to solve.

In our world, Telemetry can mean anywhere on earth, though our customers are usually in Australia. In NASA’s world, (maybe world is the wrong term for them) it can be anywhere in the solar system. Voyager 1 is currently more than 18 billion kilometres away and has been active for 40 years.

Artist’s concept of Voyager in flight

The challenge for low power consumption, is how to get the measurement from location A back to location B?

Solar Charging

The NASA solution is simple. Near sun facilities are Solar Powered, and the rest use some form of nuclear power. Since no-one will ever let us nuclear power any Telemetry device, and I’m okay with that, and we are near enough to see some sun, we will follow that option instead. And besides which, we can do it in our office and not a heavily shielded facility.

So lets recap on what we know about solar charging:

ignoring the energy cost of making a solar panel, the energy cost is free after that
there is a maintenance cost which includes cleaning panels
provided the construction is robust, they are a long life product
you have to do Maximum Power Point Tracking (MPPT) to harvest the most energy or minimise the panel size

And to get more power from a solar panel, you have to:

have more sun
have a better angle to the sun (cosine reduction)
have a better MPPT
handle lower voltages
use the right silicon

Not all Solar Panels are equal. If you want your panel to work in a mostly shady place then you might also want to use mono-crystalline Silicon solar cells because they are efficient and can continue to convert even low levels of light. In recent developments the efficiency of conversion had passed 25% as reported in Efficiency of Silicon Solar Cells Climbs and some of the stacked cell technologies are past 40% efficiency.

compact solar cell

And then you have to harvest that energy. Which is where new devices like the SPV1050 come in. Experiments in our office showed that we can charge a Lithium Polymer battery from the internal lighting. And it is a buck boost converter meaning that it can charge the battery in full sunlight (reducing voltage) and also moonlight (increasing voltage) and the device costs less that $2 in 1K pieces.

I only have one criticism. The super low quiescent current LDOs would have been more useful if they were fully independent because this would have taken another item off the Bill of Materials.

Primary Cells

The other option for Telemetry is using Primary Cells. These are not rechargeable and so must last the life of the product. We currently deploy Cellular based Telemetry modules that can run for up to 10 years from a Lithium Primary Cell or 5 years from Alkaline Primary Cells. This is ideal for Smart City style projects where the devices might be moved as they fulfil their current purpose. A good example of this is people metering or pedestrian counting where a council may want to know how much use an area is getting. Once that is understood, the Telemetry module can be redeployed and since it isn’t connected to mains power you don’t need an electrician to do that. Or they could be used to understand the level of demand of public transport services in real time so you can adjust capacity on the fly.

So there are options and as technologies like NB-IoT and CAT-M1 come online the power budget for cellular communications continues to fall. We covered this in Cellular IoT Communications. And as of last month, Telstra turned on CAT-M1 across the 4GX network.

Quectel BG96 CAT-M1 Module

Successful Endeavours specialise in Electronics Design and Embedded Software Development, focusing on products that are intended to be Made In Australia. Ray Keefe has developed market leading electronics products in Australia for more than 30 years. This post is Copyright © 2017 Successful Endeavours Pty Ltd.

arcHUB – Smart Cities case study

Posted on August 20, 2017 by Ray Keefe

Smart Cities

This follows on from our look at Smart Cities and the technology mix being considered for how you implement them. For this post we will look at the development of a Smart City Telemetry sensor suite and the ICT communications that go with it. This is also a classic IoT case study.

I also want to point out that a Smart World will only happen if we have Smart Regions, Smart Countries, Smart States or Territories, Smart Cities and Smart Neighbourhoods.

arcHUB

My thanks go to The Active Reactor Company for giving me permission to share their story about the development of the arcHUB Telemetry sensor suite which is aimed at the Smart Cities programs as well as being more widely deployable.

arcHub Telemetry Module Logo

A few days ago I had the opportunity to speak with Daniel Mulino who is the State Member for Eastern Victoria. The picture below comes from his visit to our office in Narre Warren. The original post he made along with my explanation is here. I’m giving a more detailed explanation below including some history.

Ray Keefe – arcHUB – Daniel Mulino

For those wondering about the device I am holding, it is an arcHUB Smart Cities Telemetry module aimed at Smart Cities projects and environmental monitoring where you don’t have access to, or want the cost of, connecting up mains power. This is designed for The Active Reactor Company and is already involved in one Smart Cities deployment and multiple trials of low cost sensor modules by councils and government agencies in three states. I can’t yet provide specific details on those as they are covered by non-disclosure agreements.

To understand how we got here, it helps to know the history.

The Active Reactor Company make a product called The Active Reactor. It improves both the efficiency and the life of arc lamps such as low pressure sodium street lights, high pressure sodium and metal halide lamps.

The Active Reactor

With the advent of LED street lighting their current product is not needed for new installations and so they wanted to secure the future of the business. So a great example of addressing an issue that will arise in the future so you are ready for it rather than just reacting to it once it happens.

Initially the new product was aimed at monitoring LED street lights. One of the big issues with LED lighting is that the LEDs either fail over time or they fade and lose brightness. Or a mixture of both. The fading is a result thermal diffusion in the semiconductor substrate. When they fall by more than 30% then you have to address that as they no longer comply with legal standards for lighting levels. The other catch is that the claimed life of 10+ years isn’t yet proven and so it is expected that there will be many lights that fail early or fade early or both.

Of course, once you have a communicating device that can monitor one thing and report it, it can also monitor other things and report them as well. Plus there were issues with being allowed to monitor the light. And where would the power come? Their inquiries with authorities responsible for the poles would not give permission to tap the power in the pole or light.

So this set us the follow set of constraints to work within:

must be battery operated
easy to install
low cost to make and also run
communicate using the cheapest data transport
monitor the LED light at night and keep track of the brightness trend
send an alert when it is persistently out of specification
field life to match the street light (10+ years)

As The Active Reactor Company talked to target users (initially the same people who buy their current product) and got an idea of what they wanted, a very different picture emerged. The people who cared about LED street lighting, also cared about micro climates, and soil moisture levels, and air quality, and foot traffic, and …

So that lead to a change of direction and a look at what else was required. The result is a device aimed at the Smart Cities market that also suits a wide range of other end customers and has the following features you won’t find combined together in conventional devices:

battery operated (either solar charged or primary cells)
minimum 2 year battery life for standard AA cell alkaline batteries
10+ day running time if solar charging is lost
up to 20 days on board non-volatile storage
compact form factor
multiple sensor types per node (up to 20)
sensor area network to minimise data costs
over the air firmware upgrades
over the air configuration updates
variable sample rates and upload timing
still has to be low cost to make and also run
easy to install

So here is the range of sensors already trialled:

wind speed (external anemometer attached)
sunlight level
night light level (street light monitoring etc)
temperature
PM2.5 particulate levels
PM10 particulate levels
Gases – CO, H2S, SO2, NO2, H2S
Humidity
People counting (PIR based anonymous counting)
Soil moisture levels (external probe)

It is also the HUB and coordinator of a Sensor Area Network that can include modules that can measure any of the above as well as:

vibration
shock
movement
water level
GPS location
USB charger current (for usage analysis)
counting any device or system that has a pulse output
analog voltage measurements (AC and DC)

arcHUB trial at Fitzroy Gardens

The arcHUB is solar powered and includes a cellular modem to allow reporting back to a web service. It is designed to mount to a pole using straps but can easily be mounted to a wall or any other typical structure. A typical scenario is measurements every 15 minutes (except people or pulse counting which are continuous) and uploading to the web service every hour.

With the release of CAT-M1 services across Australia by Telstra, we are expecting migrate to this communications standard because it will reduce power consumption by at least a factor of 4 which will further improve battery life.

Quectel BG96 CAT-M1 Module

The arcHUB Peripheral Modules connect via 915MHz ISM Band communications and use standard AA batteries. They can run for between 2 and 5 years depending on what sensors are attached and how often they are read and reported. If you used primary lithium cells then you can expect life beyond 10 years.

The arcHUB Peripheral Modules are also capable of stand alone operation with the addition of an internally fitted cellular modem so you can have a portable people counter module that can be easily moved to a new location and doesn’t require an electrician to install it.

And pretty exciting to also announce that this is not only a designed in Australia product range, but it is also a made in Australia product range.

Again, my thanks to The Active Reactor Company for permission to share this story and if you want to know more, leave a comment and I will put you in touch with them.

Smart Cities

Posted on August 15, 2017 by Ray Keefe

Smart Cities

A Smart City is a blending of current and emerging technologies being employed to allow a city to better manage its assets and deliver value to its residents. It is an emerging concept and still very much in exploration. The 2 core technology areas being investigated as the primary value creators are ICT (Information and Communications Technology) and the IoT (Internet of Things).

Smart City

What isn’t fully understood is the relationships between any or all of the list below:

what is worth measuring?
how to measure it (what sensor, what platform)?
how often?
in what detail?
to learn what from?
how quickly to transport the reading?
how much will it cost to transport the data?
via what technologies?
stored how?
accessed how?
analysed how?

Quite a big list.

Did you know there is a Smart Cities Plan for Australia? I only recently found out. And if you read through it there are more questions than answers. Which I think is the right balance given where we are positioned in trying to understand what is possible versus what is useful.

Smart Cities Plan

There are some obvious areas already being tackled by ICT systems. These include:

transport logistics (road, rail, freight, air, sea)
public transport
utility services (gas, water, electricity, waste)
weather prediction
environmental monitoring

And there are a range of trials underway to try and understand what using a broader sensor mix and more widely deployed sensors might do to improve amenity, even if they aren’t all very high quality sensors. Again the questions come back to:

what sensors?
how many and where?
how accurate?
how much do they and their platform cost?
measured how often?
at what latency?
what to do with the data?

Smart Cities Segments

IoT Challenges

Although the Internet of Things (IoT) has a huge promise to live up to, there is a still a lot of confusion over how to go about it. This breaks up into three distinct areas.

IoT Hardware

The first is the IoT Hardware device that is deployed to the field. These come in a wide range of shapes, sizes, power profiles and capabilities. So we are seeing everything from full computing platform devices (Windows, Linux, Other) deployed as well as tiny resource constrained platforms such as Sensor Node devices. Examples of the later are Wimoto Motes and our own FLEXIO Telemetry devices which are OS-less Sensor Nodes.

The trade offs are between:

power consumption
power supply
always online versus post on a schedule or by exception
cost (device, data, installation, maintenance)
size
open standard versus proprietary
upgrade capable (over the air OTA firmware or software capability)
security

As of a month ago, the KPMG IoT Innovation Network reported there are 450 different IoT platforms available. And most don’t talk to each other. Many lock you in. Many only work with their specific hardware. So picking a hardware platform is only part of the challenge. And new products appear every week.

IoT Innovation Network

IoT Communications

The second area of challenge is the communications. Everyone is trying to get away from Cellular IoT Communications because the Telecommunications Companies pricing model has traditionally been higher than they want to pay, and because the power required means you need a much higher power budget. So there has been a push to find other options which has opened the way for players like LoRa and sigfox.

However the CAT-M1 and NB-IoT Telecommunications Standards mean that the pendulum could easily go back the other way. CAT-M1 reduces the data rate (no streaming video needed for most IoT devices) and changes the modulation scheme so you get a better range at a much lower power consumption. And unlike sigfox, you aren’t severely constrained on how much data you can move or how often. CAT-M1 has just gone live in Australia on the Telstra network and we are about to do our first trials.

Quectel BG96 CAT-M1 Module

NB-IoT doesn’t yet have an official availability date but we aren’t too concerned about that. NB-IoT is really aimed at the smart meter market and similar devices which have low amounts of data and upload it infrequently. So a water meter running off battery for 10+ years is an example of what it is targeting. We will find CAT-M1 a lot more useful. And the modules that support CAT-M1 currently also support NB-IoT so we are designing now and can make the decision later.

IoT Back End

The third area of challenge is the back end. Pick the wrong data service and storage provider and you could find you don’t own your own data and you have to pay every time you want a report on it. And you can’t get at it to port it to another system. And if the volume of data grows the cost can grow even faster as many offer a low entry point but the pricing get expensive quickly once you exceed the first threshold.

Because of this there is an strongly emerging preference for open systems or for systems that do allow you to push and pull data as it suits you.

So our strategy to date has been to provide our own intermediate web service and then republish the data in the required format to suit the end user / client. The result is the best of both worlds. We can deploy resource constrained field devices which are low power and low cost, then communicate with high security and high cost platforms using the intermediate service to do the heavy lifting. And we don’t try and imprison the data and trap the client.

The service is called Telemetry Host and was a finalist for IT Application of the Year in Australia in 2015 at the Endeavour Awards. And again for the PACE Zenith Awards in both 2015 and 2016.

Telemetry Host

This isn’t the only approach and so we also create devices and incorporate protocols that allow them to directly connect to other systems. This includes porting our core IP to other URLs which are then owned by our clients. So far we haven’t found that one single approach suits every scenario.

Smart City

You can’t be smart if you don’t know anything. And this is certainly true for Smart Cities. To be a Smart City requires Sensors and Telemetry. But the jury is still out on how much and what kind.

Cellular IoT Communications

Posted on April 23, 2017 by Ray Keefe

LPWAN = Low Power Wide Area Network

LPWAN is typically thought about as cellular data networks but that involves a contradiction since cellular and low power are inherently in conflict with each other. For instance, a standard 3G or 4G cellular modem will have a peak current draw of up to 2A during transmission and needs to be carefully power managed if running from batteries. This has meant that a 10 year operating life from a primary cell battery either needs a huge primary cell or very infrequent communications. So what are the alternatives?

In IoT Versus M2M we looked at how the real benefit of IoT (Internet of Things) is that rather than a single Machine to Machine link being established, there are now multiple devices connected via shared web services and their combined data is being used to create extra value, and particularly if Big Data analytics is added to the mix.

SigFox Logo

LoRa Alliance

There is also a lot of potential disruption in this. LoRa and SigFox are both looking to provide lower cost networks to replace dependency on cellular network operators for coverage and also address the power consumption problem. There is an excellent comparison of these 2 systems in SigFox versus LoRa. And both are trying to disrupt existing cellular network providers. An overall view at available at NB-IoT versus LoRa versus SigFox.

NB-IoT

Which introduces Narrow Band IoT or NB-IoT as it is now commonly abbreviated to. Just to continue the confusion of acronyms, it is also called CAT-NB and CAT-NB1. There is a detailed view of this technology and its likely long term adoption at NB-Iot is dead – Long live NB-IoT.

The summary is that NB-IoT is too late to market and requires too much equipment changeover to win the early adopter market, especially in the USA, but will win in the long term. In the interim there is a host of other options also being developed. The cellular network operators have realised, at least 5 years too late, that their business and technology models were both under attack simultaneously. This is a particularly dangerous form of disruption.

Hardware is now becoming available and China adoption of NB-IoT makes them the main early adopter market.

Quectel BC95 NB-IoT Module

u-blox SARA-N2 NB-IoT Module

Low Power Cellular

So if up until now, low power and cellular were not usually compatible concepts, what is changing to address that?

To reduce power consumption, you have to have one or more of the following:

reduce transmit power
increase receiver sensitivity
reduce transmit duration
increase transmit interval
reduce network registration time
reduce data rate

Some of these can be mutually exclusive. However the key elements that are working together is to reduce the data rate and use a modulation scheme that means the transmitter power can be reduced. LoRa does this very well and NB-IoT is looking to achieve a similar thing. There are trade-offs and the lower data rate for NB-IoT means it is best suited to very small packets. CAT-M1 will require less power for larger packets because the faster data rate means the transmit time is a lot shorter.

Low Cost Cellular

So we have looked at the power consumption angle. How about cost and business model. And there are two aspects to cost. There is the hardware cost and there is a the network operations cost. To reduce cost you have to do one or more of the following:

reduce silicon and software protocol stack complexity
high volume production allows economies of scale for hardware
increase the number of channels available in the network
increase the number of simultaneous connections in the network
reduce margins

Both SigFox and NB-IoT aim to make the end device hardware cost as low as possible. In the case of NB-IoT and CAT-M1 the channel bandwidth can be reduced and so the same bandwidth can support multiple devices instead of just one. The power level in the device transmitter is reduced by reducing the bandwidth and data rate. As an example, a CAT-M1 module has a peak transmitter current draw of 500mA which is a factor of 4 lower than CAT-1. So low cost and low power can go together very well.

The graph below shows how the various cellular standards relate to each other.

Cellular IoT standards and how they relate

IoT Deployment Options

We have been using standard 3G/4G Cellular modems for our broadly distributed IoT offerings. As of the end of this month, we ship our first CAT-1 based offerings. These have the advantage of supporting both 4G with fall back to 3G. Although NB-IoT hardware is available now from both Quectel and u-blox, the networks in Australia don’t yet support it. And while NB-IoT is ideal for fixed location assets, we also do mobile systems so these need to be CAT-M1 once it is available.

CAT-M1 is expected to be available in Australia on the Telstra network around September 2017. I am also taking this as meaning that NB-IoT is 2018 or possibly even longer. So we plan to move to CAT-M1 as soon as it is available. The modules are expected to be available about the same time as the network upgrades.

Here are some CAT-1 and CAT-M1 offerings from Quectel and u-blox.

Quectel BG96 CAT-M1 Module

Quectel EC21 CAT-1 Module

The Quectel EC21 is what we are deploying in our units later this month.

u-blox LARA-R2 CAT-1 Module

u-blox SARA-R404M CAT-M1 Module

IoT Network Upgrades

Ericsson have announced the roll out plans for the Telstra Network CAT-M1 capability.

And Telstra have announced their own Telstra IoT Network Plans.

That is the overall Telstra road map. Summary:

– CAT-1 now
– CAT-M1 by September
– NB-IoT sometime after that but no dates yet

Other carriers will follow although Vodafone are well placed to introduce NB-IoT first as they have Software Defined Radio base stations from Huawei and so can roll it out as a software update.

Connect Expo 2017

Posted on April 7, 2017 by Ray Keefe

Connect Expo

The Connect Expo is on each year around late March in Melbourne at the Exhibition and Convention Centre. I had gone to previous events but this was our first time as an exhibitor.

Connect Expo – Successful Endeavours

This was by far the best Connect Expo I have been to. The mix of software vendors, web platform vendors, component suppliers and specialist IT vendors was excellent and there was also a specific section for eHealth. We set up our own IoT Platform demonstration with a QR code you could scan with a phone and take you to a webpage showing real time (less than five second delay) updates to the status of a device on the stand. A simple demo of the Internet of Things in action.

A really good trend I noticed was several Software Testing companies represented in the mix. Testing to confirm software is working correctly is a very important part of delivering a high quality product and it was good to see this coming through at the industry level.

We also shared the stand with Minnovation who do data science and analytics so it was also good to see how rapidly that area is expanding.

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Tag Archives: IoT

Solar Charging Improvements

Powering Telemetry

Power Consumption

Telemetry

Solar Charging

Primary Cells

arcHUB – Smart Cities case study

Smart Cities

arcHUB

Smart Cities

Smart Cities

IoT Challenges

IoT Hardware

IoT Communications

IoT Back End

Smart City

Cellular IoT Communications

LPWAN = Low Power Wide Area Network

NB-IoT

Low Power Cellular

Low Cost Cellular

IoT Deployment Options

IoT Network Upgrades

Connect Expo 2017

Connect Expo