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element14’s energy harvesting design challenge: the winning entries

element14’s energy harvesting design challenge: the winning entries

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By eeNews Europe



Whether that’s something as noticeable and immediate as an overheating laptop, producing a huge amount of heat energy that wastefully dissipates (and burns!) its user’s lap, or more easily overlooked wastes, like a TV remote that is constantly using low quantities of battery power.

When we launched the element14 Energy Harvesting Design Challenge we did so in the hope that it would highlight the potential of the technology in future electronic applications, inspiring engineers to take advantage of wasted energy.

Using energy harvesting within a remote control is one of the few uses of the technology that has made it into consumer electronics already, so it was pleasing to see that one of the entrants, Electronics and IT industry veteran Monte Chan, had the same idea and set about producing his own battery-less remote control. In any other contest his final product, with such an obvious and universally appealing concept, would have been the winner.

However this wasn’t any other contest. Since its inception, the Energy Harvesting challenge was looking for the project with the most potential for being developed in to a tangible, real-life product. But our two winners submitted designs that went beyond simply being feasible products. Instead, they offered potentially life-saving benefits for people around the world, something we could never have expected.

Our first winner was Victor Sluiter, whose egg timer idea evolved in to a fully formed food safety device. What was great about Victor documenting his build on the element14 community was how eloquently and clearly he explained where he needed to adapt his design to suit the limitations he came across. Some were the result of completely unavoidable limitations, such as the timeframe forcing him to produce his own PCB design, whilst others were chance discoveries that developed naturally from Victor’s own limitations, including the entire concept of developing something unrelated to showering because he couldn’t devise a good enough mount for the peltier.

The second was Wojciech Gelmunda, with his ground breaking carbon monoxide detector. By tapping in to the heat energy wasted by household piping on a daily basis, Wojciech managed to design and produce a detector that doesn’t ever run out of battery power. Anyone who owns a detector should be able to see the immediate benefit of this, with the repetitive ‘low-battery’ warning sound often proving incredibly irritating for anybody in earshot.

There is a far more serious benefit to this technology, which is why Wojciech’s design was ultimately selected as one of the winning entries. Many home owners will have let their detector run out of power in the past, through apathy towards the warning sound or the complete lack of a warning in the first place. When the detector is out of power, it puts all members of the household at risk, thanks to the notably silent-but-fatal nature of carbon monoxide poisoning.

A single unit produced in an amateur developer’s house – the bathroom to be precise– may not be the most compact, aesthetically pleasing, or cheapest of products, but it is realistic to envisage a time when this is tweaked and mass produced. In other words, this project could develop in to a cheap, forgettable device that can be installed in homes throughout the world, potentially saving many lives.

Victor’s project offers similar future potential. Whilst it was designed to perfectly cook an egg, right down to the yolk, at the heart of the project was an attempt to solve a problem that would make full use of the computational power of the EFM32. In this case, it was using the board microcontroller to calculate the ‘hardness of an egg’ via sensors that monitored the temperature of the boiling water in the pan – a concept that can clearly be adapted to create a guaranteed water sterilization device, for use in third world or disaster areas.

Both our winners stressed how difficult the reality of energy harvesting is. Victor in particular now admits he was overoptimistic at the start of the challenges as to what is possible today with energy harvesting. Originally intending to make an LED bike light that was powered by the vibrations of the bike frame, this plan was swiftly shot down when he realised that the piezos attached to the bike only produce power in the microwatts, rather than milliwatts. This was the first major problem both engineers encountered, with energy harvesting requiring smart, out-of-the-box thinking to successfully bypass the limitations of the method.

The second was one that Wojciech expressed particular difficulties in getting around, eventually requiring a degree of lateral thinking to bypass. Energy harvesting is not like standard energy sources, in that there are few sources with a constant, steady supply. As a result, handling this energy is much more akin to managing renewable energy, requiring a highly efficient method of storage to bridge the ‘gaps’ in supply.

In fact, what united all entrants and their difficulties was the need for a very carefully considered approach to the design process – far more than in any other project. Ahead of time, the engineer needs to consider every single component that will be in the final product and its requirements, with no-leeway for mistakes; low-energy components, energy optimized analogue circuits, energy saving orientated code, low power sensors, and DC/DC converters were all considered by our winners. These then need to be matched to a power supply that can meet their demands, with an efficient way of storing and retrieving energy at any time.

So it was quite an important point that Wojciech made about the ability of the present day super capacitors the entrants used to store energy in this way. In particular, he noticed that the super capacitor leaked current at an alarming rate, resulting in a far more difficult challenge in bridging the ‘gaps’ in the power supply – likely the reason many entrants were not yet confident enough in their designs to completely remove a fall back battery for moments when energy harvesting alone is insufficient.

This is why energy harvesting is such an interesting and exciting design area to be involved in. It’s still evolving, with many areas being open to improvement, giving engineers the chance to design something that truly push the boundaries of what we thought was possible with this technology. If we return to the humble remote control for a moment, Monte Chan’s battery-less device is not a world away from the batteryless piezo remote debuted by Arveni two years ago. These are devices that still only reach a niche audience, with a hefty price tag, despite that fact everyone can appreciate their utility.

So what’s next? Well as briefly hinted at on the Energy Harvesting debrief Hangout yesterday, everything learnt during this challenge has been considered and taken in to account by the engineers behind the kit, which will form the basis of the Energy Harvesting demo kit 2.0.

As for the winners of the contest, not only have they presented to the whole world working, innovative devices, but element14 has sent them each a bundle of goodies from Würth Elektronik, Energy Micro and Linear Technology. Having already proven their worth as top class designers, what they do with this kit will be worth watching.

About the author
Dianne Kibbey is Global Head of Community, element14 – www.element14.com

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