Beyond the kettle: How Heatle boils down IoT efficiency into business value

Ruth: Wow. That sounds like quite the journey from aerospace to tea kettles. Why kettles?

David: As a kid, I've always looked at kettles growing up. They're very common and popular in the UK and globally actually. And I've always been fascinated with how they worked.

I've been like that with all things, actually. I always like to know how things work. I took things to pieces as a kid. But I always noticed that kettles are often overfilled. They get dirty inside of scale and calcium. And even as a kid, I was always switching off the kettle manually because there's a bimetallic strip inside the kettle, which heats up with steam and turns off the kettle automatically.

So that's the same on every kettle. Everything from the cheap ones for 15 euros, right up to the more expensive for a few hundred, they basically rely on a bimetallic strip. And those things are very slow and lazy to turn off. So consequently, you get unwanted heating like 30 seconds at two to three kilowatts.

Even years ago, I looked at this and did some basic maths on the back of an envelope and could tell that there was a huge problem because in every home and office globally, these kettles are not only being overfilled, but they stay on for too long. And the kettle was one of the most energy hungry devices in any home.

So, I always had this irritation at the back of my mind that I wanted to do something about kettles. And at this point in my career, I had the opportunity. So that's why we started Heatle.

Ruth: Fascinating. And what is it that, what do you do differently? What did you change about the way a kettle heats water?

David: So, a kettle heats water via resistive heating, technically it's 100% efficient. It has mains AC applied to a resistive element that's made of micron wire. It's at the bottom of the kettle and in an ideal scenario, that system could be a hundred percent efficient, but in reality, as a product, a kettle is, like I said, overfilled, it stays on for too long, but also the resistive heating element is quite far down in a kettle and not in contact with the water.

It can't be because of safety reasons, so it's insulated. So those layers of insulation and the whole thing, the whole body of the kettle that needs to be heated up, that all adds to the inefficiencies. So, what I wanted to do is heat the water in the cup only what you need and the most efficient form of heating is induction.

So, it works like a transformer. You have a primary and a secondary side in induction heating. The primary side is in our case, in the Heatle, under the glass. So that's a 13-turn coil with an inductance of about 65 micro-Henrys. And then the secondary side to this transformer is the disc.

And the disc goes into the liquids, and it gets hot through eddy currents being produced in the disc. And so, the disc makes the secondary, it's like a one turn coil, so it's a huge step-down transformer from a high voltage on the primary side at 1,200 volts. Right the way down to only about three and a half volts, but a huge current in the circling around the disc in hundreds of amps.

So that's how it works fundamentally. So, behind that, you need an oscillator and safety and control and a user interface. So, it was designed with the fundamentals in place in order for the customer side to heat any liquid in any cup. So, it could be a bowl, it could be a plastic or paper cup, it could be a plastic cup.

Even plastic cups. So, for example, the reusable cups. Many of our customers give us feedback and pictures on Instagram and they're using their reusable cup at home, reheating coffee and things. So, it's very flexible, for baby milk and for soup and all kinds of things.

So, I was always interested in this because it seemed to solve a few problems, saving energy, making a better user experience. So that's why my focus was on this and nobody else had done it before. There were some startups in the past that had a go at this in Germany and in France. The more we worked on this, the more we discovered these things that weren't exactly public, and some were, some weren't.

We realised all of them failed for different reasons. They could only achieve a power level of about 300 watts, and that seemed to be a ceiling of functionality because of the way in which the system had to work. And that was really my focus to solve that fundamental power electronics problem.

And I did that. And then from that fundamental foundation of the electronics. The rest of the system was built, the user interface, the packaging, the plastic case, so it was designed from the inside outwards.

Ruth: Okay. And what challenges did you face? So, you said you broke the power barrier that set you apart from the competition. What other challenges did you face?

David: Right. So, the power barrier that seemed to be the ceiling was because most people, including myself in the beginning, try to achieve the power electronics with a half-bridge driver circuit, which is very common.

It involves two big transistors, MOSFETs normally, that drive a series or parallel resonance circuit. So that's fundamentally how it works. The problem is the secondary side of the coil; the disc that I mentioned is variable. Its inductance, its resistance, and its characteristics change a lot because of the distance away from the primary coil. It could be a thick base cup. The disc can be moving with bubbles. There are many factors that can affect how this works. You need a very, basically, in any oscillated system, you need a feedback loop. And the problem with this half-bridge topology that most people use is that the feedback loop is loose.

It wasn't tight enough. So, the transistors are hard switching. And we got a lot of help from some of our distributors and suppliers, including Avnet, who supplied our transistors. Silicon carbide MOSFETs, actually. And what I did is I designed a custom topology that uses analogue feedback, so there's no opto couplers involved.

And with that, it was able to self-tune its resonant frequency on the fly very quickly. I mean, really in the nanosecond domain. And that allowed the driver circuit to not overheat, basically. So that was the fundamental part of the electronics. The system has to be controlled and from that become all of the software and the safety systems that really are also fundamental to the design.

Ruth: So, most of the people, I assume they already own kettles. How did you convince investors and customers that the world needs another heating device?

David: Right. That's definitely a challenge because what we discovered is there are many marketing avenues you can take on a product like this.

So, there's just purely energy saving, which really appeals to perhaps the green market. And then there's the more kind of premium products that has features, functions, and benefits similar to an Apple products perhaps. And then there's like the kind of the geek, nerd scientific aspect.

So, all of them have different characteristics, how does it look? How does it work? So really, during the market research, it was discovered that the market group is actually broad. And that actually makes the marketing quite challenging because you can't pinpoint your marketing in one place and put all your power and money into that.

It includes families, single people and students, mothers to be with baby milk and baby food, coffee market, tea market because the device is so flexible. So, what we did is we designed a product that looked nice and was easy to use, and that was the main target. And that's actually difficult to do because it's very easy to put lots and lots of features into this.

But to make it look sleek and simple and easy to use is more challenging than adding 50 buttons. So that was the challenge.

Ruth: For our listeners who have not yet in parallel Googled Heatle, it doesn't look like a water kettle, which is nice 'cause I hate the water kettle in my kitchen because I hate kitchen appliances, for example.

I think I would be like the, I would be the tech geek target group for you that also likes a nice design, right? Those water kettles are not pretty, they're just these ugly, bulky things that take up kitchen counter space. And so how do I describe it?

David: It looks a bit like the Qi chargers for charging your phone, these discs?

Yes. With a power cable. It's a bigger one of those. So, it's actually about 18 centimetres in diameter and about six centimetres tall and weighs about two kilos. It comes with three-disc size options, small, medium, and large. So, the small is good for the baby bottles. Medium is supplied as standard; that's four and a half centimetres.

It fits into most cups and glasses. And then there's a large disc, which is really for transferring more energy. There's more coupling between the primary and secondary, and that large disc is really good for large volumes of water, and particularly where the base of the cup or the teapot tea strainer is really thick.

So, the power drops off exponentially with distance. So, the further the disc is away from the primary coil in the base of the Heatle, the lower the power. So, in order to counter that, you can use a large disc if you like. So, these are all optional accessories you can purchase. And actually, that's where the story started for Heatle with the accessories.

There's a whole range of accessories we have now and discoveries we made for other uses for the Heatle. There's things like the hot water bottle, the Wärmflasche, tea filters, cleaning sets, holder discs for where like glass trays, for example, where you put your discs after use, a whole range of things.

Which really came from the customer community. So, we reached out to them, we gave them polls and questions, and we listened to our customers. They had suggestions so they could vote on ideas. They could also as an option to see, for example, they can propose their own ideas. So, we took those things, and we developed products.

In collaboration with our customers. And that is a huge step in development for the product with improvements and particularly around the user interface. So, we're going to be using NFC tags, for example. So, working with Avnet, they supplied us with NFC solutions around St. Micro actually.

So, they make a whole range of NFC tag readers and writers. So, we're actually incorporating NFC read write into the new Heatle. Now that's, NFC is nothing new. It stands for near field communication. And the tag is passive, and it's energised by the transceiver that's reading this thing.

And that's just over, I think it's 13.8 meg frequency and it is a tuned circuit inside the tag. So, these things are used in products and in your phone and in payment cards and business cards. Energises that and sends a small amount of data. So, what we want to do is we want to set the Heatle parameters automatically.

'cause currently, the customers are choosing the power, time, and temperature manually, right? So, using this knob from the front, they can rotate. That's an LED display. And they can choose high power mode, low power modes. They can choose profiles like baby mode, for example, for baby milk.

And they can do all kinds of things, but some of the feedback we got from customers is it's fiddly, and it's a lot of menus and sub menus. You can set the temperature steps in one degree, five degree, or 10 degrees. You can do that in settings. So, all of those things we want to make easier for our customers.

So, when it comes to settings, we are going to use our app, our mobile app, and that's, we'll have a page where you can do all your settings on there of a nice GUI graphical user interface. But when it comes to actually setting the power, time, and temperature. Then we're going to do that with NFC tags. So, we have a range of teas already.

Custom teas, very premium. But tea is something that should be heated to the correct temperature, we have these presets. So how about putting an NFC tag on our tea bags? We have these big tea sacks that we sell. So the

Ruth: NFC tag is on the back, and then you put the tea.

Exactly. So, it's on the product.

David: And that thing is really simple to use. You just hold the teabag near to the Heatle in the correct location. It's just to the left side. And it will read and set the power, time, and temperature. So smart

Ruth: tea.

David: Right. And it's just simple. Really. Of course, the customer can do it manually. But we've made the process simple and easy, and it's the same for our accessory. The Wärmflasche the hot water bottle. It, that should be heated to 80 degrees. And we supply this hot water bottle, which has temperature feedback built into it.

We supply it with special liquid inside, so the customer doesn't need to pour it themselves and risk burning or overfilling, or using a hundred degrees, all of those things shouldn't be done. So again, that's a brand-new creation and it's a premium silicon hot water bag that we manufactured ourselves with a lovely cover.

It's a special wool cover, very soft. Again, you need to set these three parameters manually, the power, time, and temperature. So, we have also put in the tag around the neck of the hot water bottle and NFC tag. So again, you put your hot water bottle on there when you want to heat it up and it would automatically set these parameters like 80 degrees, for example.

So that's something that's clever we're bringing in. And it's, like I said, it's not a particularly new technology, it's just a new use. So that's really a lot of what we do, and we're taking a very old fundamental technology like induction heating. And adding a new digital layer.

We're abstracting that. Such that the customers find it easier to use.

Ruth: It is incredible how many use cases you found around such a simple technology as just heating liquid or heating liquids. Right. That's really, that's really, it's just the beginning

David: Actually, because there's the whole coffee industry, so the moka pots, for example, this is the two stage metal pots.

It was originally invented in; I think it was the fifties by Bialetti. You may have one.

Ruth: I have. I use one of these for my espresso.

David: Right. And it's very common. If you look at the Bialetti Coffee pot on Amazon, it's got almost five-star reviews from many thousands of customers.

So, it's still very popular, but it has its drawbacks. Just like the hot water bottle, it's something that gets heated, but there's no temperature feedback. So, we are actually working on a really cool product. It's in its latest development phase now. We're going to get it manufactured soon.

It's a moka pot with temperature feedback. So automatically turns off. So that avoids again, overheating. You can overheat the coffee. The

Ruth: coffee gets bitter if you make it too hot, right? It does. It really does. And then it kind of burns the whole thing.

David: It does. It burns. And particularly on a gas or electric or induction cooktop, it's very easy to perhaps walk away whilst that thing's heating.

'cause it takes like five minutes to heat. And then it goes crazy with the vapour pressure. The water expands to 6,000 times its volume when it's in a gaseous state. So, there's a huge amount of pressure down there and it pushes up and it goes through the coffee into the top chamber, but there's no feedback.

So, our product has simply got a temperature sensor in the top chamber, and when the water touches it and the Heatle recognises the rise in temperature, and it shuts off the base. It is really as simple as that, but just that innovation. It's made the product completely usable so you can just put it on the Heatle.

And again, an NFC tag can be on this, so it just does it automatically. It's very quick and easy. So that's really the definition, I think of the Heatle to make your life easier in the kitchen. It's one device that does many things. It's easy to use. It saves energy, saves money. You don't need to clean it.

That's right. Well, actually. You don't have to clean the base so much. The walls of a cooker. The kettle does get completely filled with calcium. Right. I hate it. But the discs also our disc, our metal discs, they do also get calcified. And also, if you use it, if you heat it, milk and hot chocolate, it does need to be cleaned.

So, the cleaning feedback from our customers, actually we found the cleaning is actually quite challenging. So, we developed a cleaning kit like you would get for your coffee machine. Or your dishwasher. And that we thought

Ruth: about everything. We had to. That was

David: actually, quite crucial because the disc really does get calcified over time. It tends, but it depends on the hardness of the water in your area in Berlin, particularly hard. So, we have a cleaning set. It's completely bio-organic, and that thing is basically made, the liquid's made of concentrated lemon juice. And it works really well. We have a cleaning mode and NFC tag, and it cleans the things really well.

They come out like new in about 30 seconds. So that's one of the things in the ecosystem that we've worked on.

Ruth: Very nice. And are you thinking also about broader smart home integration use cases?

David: Definitely. We do want to integrate to the general smart home topology.

Like, Matter is now very popular. Most people in their homes have some kind of smart device like Alexa or Google. So, we would connect to this, and we are working on this. But we are not going to connect in the way some smart devices connect to your home. I mean, we don't see the need to start the Heatle automatically using a voice command.

This unnecessary smart layer. I mean, there's no point for that. But where it could be useful is integration with our app. So, if you want to use the app with the Heatle for software updates or looking at the analytics, you don't have to be right next to Heatle. You could be on the WIFI in your house.

That connects to the Heatle, and if you want to look at your energy savings on the energy savings tab of the app, you can look at how much energy you've used in kilowatt hours, and you can even see comparisons of how much energy you've saved to a typical kettle.

Ruth: We will take a short break.

Stay with us. We will be hearing from our guests very shortly. This podcast is brought to you by Avnet Silica, the engineers of evolution. We help you bring secure, intelligent. And connected products to market. If you want to learn more about us, we have put information and links in this episode, show notes, and you can also connect with us on LinkedIn or Avnet-silica.com.

That's A-V-N-E-T dash S-I-L-I-C-A.com.

You mentioned data and analytics now quite a bit, and I think in our briefing call you mentioned that you're now also starting to make use of the data that you're collecting from your customers. Can you elaborate on that?

David: Sure, sure. And the first thing to say fundamentally is data privacy is very important.

So, for any customers that want to opt in,

Ruth: You are a German company. I can tell.

David: Fundamental. So, any customer that does want to opt into this. Can share their data and so we can, in our platform and even including the customers with their login can actually look at, like I say, the energy usage.

So inside Heatle, we measure the voltage and the current. And we also measured phase shift between the two-power factor. And the Heatle was designed for a very good power factor, almost one. And I achieved that with the type of drive electronics I use as part of my DC link. I use a very small DC link capacitor, so that doesn't create too much of an offset between the voltage and current, which is really important.

So, you use all of the energy that you're getting, it's less reactive. Power. So, you're using a real power, and that's fundamental. So, you can look at these factors from the data that comes in. So, if any customer's having challenges or issues, or if there's a warranty case, if they've perhaps broken a glass or if there's any issues, we can ask for their permission.

They can check a box in the app. We get the last 20 seconds of usage, and we can look at, what's the current, when it's scanning, when it's looking for a disc? What's the power when it's running? We can do some basic analytics and if there's a need to have a warranty case, then we handle all of the warranty cases ourselves and we have an efficient system and we can change a glass, for example and send it back to the customer within a few days.

Ruth: And so, you use it for support and warranty use cases primarily? Or are there other

David: Sure, sure. So, like on your phone you can have software updates. And again, for any customer that would like this, they can have a software update. So, inside the Heatle, we have a main processor, chip, actually a PSoC 5LP, which is a really nice microcontroller.

It's not the newest thing, but it's very reliable. And it has these digital building blocks inside. So, this is logic that can run without software. So, we can use that in a safety layer, for monitoring things. With comparators and op amps, we can monitor current and temperature and things.

And also, fundamentally there is Bluetooth inside there. So, we use a Bluetooth module and that's nRF52832. It's a module that's supplied to us and that allows a connection. Like the phone, for example. So, the app can connect to this, and we can update both of those devices inside the Heatle, securely encrypted updates.

So, to update the Bluetooth chip and also the target microcontroller can also be updated via the Bluetooth. So, if we want to roll out any new features or functions such as the hot water bottles, a coffee pot, all of these things, even a request from customers was to adjust the temperature in finer steps.

The original software adjusted temperature and 10-degree steps. And we thought that's all customers would need. But actually, we were wrong. So, we changed that and lots of the customers, and we can see how many, for those that have opted in, have updated the software. And then it gives the one-degree step if you want that.

And that can be useful for some people Personally, for me, my Heatle will adjust in five-degree steps. So that's good.

Ruth: What other user patterns have surprised you most?

David: One of some of the new accessories that were bought in were around consumables, tea, mulled wine at Christmas.

These things really surprised us. It's like mulled wine. That's right. And again, with mulled wine, there's this need to not overheat it, you don't want it too cold. So, there's this same as power time and temperature needs. And so, this was introduced, and we were really surprised how popular that was.

So, these consumables and also the liquid for cleaning. So those things we didn't expect but came later. And there's this interest.

Ruth: It's really cool how your product evolves also around the experience the users make and then feedback that to you. That is really cool.

David: That's right. So, we are trying to better communicate in this way. And as in our startup phase. We tried our best, but now we are really improving with this, even with regular tech videos. Short, 30 second videos, this just shows things like whilst the Heatle's heating, you can rotate this knob on the front and you can see other things, metrics, like the power and the target temperature, and the live temperature from the rod.

So, we actually measured the temperature inside this rod that goes into the cup. We measure the temperature there. And there's a small digital temperature sensor there that's connected on I2C up to the microcontroller at the top small antenna, an LED that shines up through a window and the rod.

Is another interesting part of the Heatle. I think it's one of the key parts actually, this rod is magnetic, and it connects automatically, like it connects to these discs. That also have a magnet inside. And that was a challenge to design, but a challenge that we had to overcome because we wanted to measure the temperature in the cup or in the product, like the hot water bottle.

And what we started with was batteries, small batteries inside the rod and tried all kinds of things. Alkaline, replaceable batteries, lithium polymer batteries that could last a long time. It could be recharged. Super capacitors were put in in some of the early prototypes. But that created problems because if you need to ship your product globally as we are starting to do, you have to take care of battery safety, management, safeties, all the safety regulations regarding that.

Even with production, if production is overseas, it's not easy to ship lithium. Large quantities as well of lithium cells. So, I designed it to work without batteries. So, it uses energy harvesting. So, inside this small rod, which is six millimetres diameter stainless steel.

Non ferromagnetic. So, it's a 300 grade. It has a receiver coil at the bottom that was custom designed. And the energy field from the base, it's like a torus shape, like a donut. It picks up energy from the base. And it charges a bit like Qi charging actually, and a bit like the NFC tags, that harvest energy.

We take the energy from the base, the resonant frequency down there is around 24 to 28 kilohertz, and it goes through a small rectification circuit inside and a bank of normal MLCC, that's ceramic capacitors. A bank of those holds enough charge to power the radio and the temperature measurement only whilst it's heating.

That's actually, we realise that's only when you need it. You don't need the rod to be on 24 hours a day. So, whilst it's heating the rod powers up and then it starts reporting its temperature down to the base. And that works. So that was pretty cool to have that work. And so, it makes a nice slender rod.

As I said, six millimetres diameter, the wall thickness gives us an inside diameter of 5.4 millimetres, so the PCB inside. At five millimetres, slides in and fits perfectly and allows us to work without batteries. And it just looks a lot better.

Ruth: I can imagine that for enterprise or commercial users, it will be all too interesting to integrate the Heatle into like a kitchen counter.

David: Right. Definitely. That's a good point. Thanks for the prompt. That's actually something we're working on. Again, we listen to customers, and they said almost exactly the same as you would be nice if it was integrated in. So, we have done that. And basically, the Heatle case, the Heatle, the way it looks, we can take off the outer skin of the Heatle.

We can replace it with like a metal frame that has tabs with holes so it can screw up underneath a counter. Countertop. It can work through the induction field. The electromagnetic field can go through any non-ferromagnetic material, glass, ceramic, wood, polymers, it can work through those.

So that's what we started to do. And we have some demo units also works great in sinks, in actually the sink because, oh, this is again, was feedback from our customers. Can we fit it into a sink? Why? How? We made some prototypes. 'cause

Ruth: that's where the water goes automatically. Exactly. It's exactly

David: the right place to have the Heatle actually. Because you need to fill up with water, you need to perhaps empty a cup. You need to rinse the disc after use. You're right next to the tap, so why not? So, in collaboration with a large kitchen sink manufacturer, we've developed a range of prototypes.

Which work really well, and the fact that we've got Bluetooth in the Heatle with this Nordic nRF chip. We can have a remote control. So, this remote control that can control the Heatle, start the scanning, set the power time, temperature. All the NFC tag can be on the counter surface.

Or near to the sink. Right. So, this little remote control we've got and the prototype's only a 3D printed thing. Again, it's got a little Nordic chip in there. It's magnetic and it can go anywhere in the kitchen. You can even clip it up underneath the work top cupboards. And it can be different colours.

You can have wood, metal, plastic, red, green, whatever. So, it matches your kitchen. There's different facets that go onto it. So, it that has to be battery powered. But the cool thing is in our prototype we have a coil in there, a receiver, a coil, and you hold it next to the Heatle, you click charge and it will charge that thing and it will last for months.

'cause it goes in, it drops into a low power mode. We wake up the Bluetooth chip in the remote control with an interrupt so it can go into a deep sleep with a button press it wakes up. So that's another use case that's coming soon. And that's really more of a business-to-business type.

Things. One of our investors is actually in the kitchen industry in large scale distribution and has a huge platform that the kitchen manufacturers and distributors use. So, we already have a good soft entry into that market, and that's something we're really looking forward to.

Ruth: It's incredible. I would not have expected that an episode about water kettles would fly by so fast, but we I think we are almost at the end of the show. It is really incredible to learn that when you listen to your customers, create a great user experience, how many use cases and how many new ideas can come up and make a terrific product.

It sounds really exciting.

Ruth: The only thing I have left to ask you is the most difficult question of the show. If you had to put together a soundtrack for this episode or your company, what song would you put on it?

David: Oh, wow. Well, personally, I like James Lavelle, the artist, and the particular track is called Sweater Weather.

The remix by James Lavelle. I listened to that most mornings coming into work. It was a soundtrack really, to the development side. Nice. But also, as a cliche, it could be any song to do with getting hot. So, there's so many song titles about things getting hot in here. Sure.

Or something via the blues bands, Canned Heat or something to do with heat. I was also thinking

Ruth: about the heat is on. Exactly. Something,

David: something like. So that would be a good cliche.

Ruth: I will put it on the playlist.

David: Good. I look forward.

Ruth: We have a playlist on YouTube and on Spotify where we collect all the contributions from our guests.

Nice. So, thank you David. It has been terrific. The time flew by so fast. Thank you for being on the show. It was really insightful and thank you for sharing all your expertise.

David: Thanks for inviting me. Thanks for making the time to listen and much appreciated.

Ruth: Thank you for listening to We Talk IoT. Stay curious and keep innovating.

This was Avnet. We Talk IoT. If you enjoyed this episode, please subscribe and leave a rating. Talk to you soon.