The initial proposed solutions for the smart-garden project looked awful. The battery would be depleted in a month. It would have taken weeks for a typical over-the-air firmware update.
Repeaters would be necessary in anything larger than a modest lawn because the radio signals were propagated so close to the ground that the waves simply bounced upwards, affecting range by a factor of 1 out of 5.
The Gardena smart-garden solution required solving a complex problem with many factors. Batteries can last the entire season, over-the-air firmware updates take less than 10 minutes, and even larger-sized lawns will need no repeater.
Fulfilling requirements for long range, low power and high throughput is not easy. But it's often the requirement of a commercially viable IoT solution. Over-the-air (OTA) firmware updates can represent a major savings in after-sale support and increased satisfaction for their customers. Instead of recalls and physical service visits, fixes are delivered seamlessly and locally. Think if the Volkswagen diesel snafu could have been solved with over-the-air update technology.
OTA firmware updates is in fact one of the fundamental wins of making a conventional product a smart product, and a major incentive for the Husqvarna group, who owns Gardena along with their American pendant, McCulloch. But it was only one of the many values of their smart-garden solution, which allows for scheduling of mowing and watering in conjunction with input from a humidity sensor device included in the smart-garden suite.
So how did Seluxit achieve the impressive figures of a range of 6 kilometers (1 kilometer close to the ground) and a throughput of 100 kbit/s at about a hundredth of a Watt for the Gardena solution?
The technical answer is a highly-connected interplay of hardware and software-related factors. The hardware needed to be specially tuned, including notably the antenna. And the stack and platform use highly efficient compression algorithms to reduce air time. The Lemonbeat stack was designed by Seluxit in conjunction with Lemonbeat's owner, the German utility company RWE. The full stack features wake-on-radio technology on the sub-GHz ISM-band, using FSK with listen-before-talk and adaptive frequency agility, to effectively solve the duty-cycle-limit problem.
The non-technical answer is that the results were achieved through a mixture of expertise, experience and attention to detail. The long-range, low-power and high-throughput solution was as tailor-made for the smart-garden use case, but there are many other use cases that can benefit from this sought-after IoT cocktail.
Daniel Lux is CEO of Seluxit. Born in Germany, educated in the Netherlands, and residing in Denmark, Daniel's outlook is distinctively international. Aside from extensive technical expertise and attention to detail down the stack, Daniel is especially engaged with high-level IoT concerns such as security and device interoperability.
Edited by
Ken Briodagh