World's smallest Bluetooth location 'stickers’, StickNFind, locate misplaced items from smartphone app using Nordic Semiconductor nRF51822 SoCs

StickNFinds are the size of a U.S. quarter at just 0.98-inch (24mm) in diameter and 0.16-inches (4mm) thick. Users can easily track up to twenty location stickers on a smartphone app. Stickers can be used to track keys, remote controls, pets, and even people. Using a free smartphone app users can locate their stickers using a 'radar screen', set distance alerts called 'virtual leash', and more.



StickNFind was created from U.S. crowd-funded startup Stick-N-Find Technologies (a subsidiary of RF design firm SSI America - see 'About Stick-N-Find Technologies' below). Each tag retails for as little as $20 and is said to be able to operate at a range of more than 100 feet (30m) and run for a claimed industry-leading one year from a slimline CR2016 watch battery.



Bluetooth low energy location sticker from StickNFind, using nRF51822 SoC



StickNFind is offering developers a free software development kit and technical support with its stickers already being developed for use in a wide range of applications including automated inventory tracking and monitoring within shops, stores, and shipping crates, plus security tracking of high value items such as precious stones and expensive tools or equipment.



Making the tags fit into a coin-size form factor, however, was extremely challenging. The first problem was the antenna, recalls Jimmy Buchheim, Founder of Stick-N-Find Technologies. It had to be omni-directional over a range of up to 30m line-of-sight while being sandwiched between a watch battery on one side of the tag and a buzzer on the other: both acting as RF shielding. In addition there was no space for a regular battery bracket, which meant it had to sit within the tag unfixed and free moving which meant its RF characteristics were also continuously moving. We went through five different 'trial-and-error' designs before we got this right.



Buchheim continues: The next major issue was battery life. Our philosophy was that this product had to be 'stick and forget' to win over consumers and that meant a one-year battery life. This would have been fairly straightforward with a regular CR2032 watch battery, but with a slimline half-capacity CR2016 – which was all we had space for – we had to minimize everything that consumed power including crystals, inductors, power collators, and of course the RF chip itself.”



The Nordic nRF51822 stood out from the competition for many reasons, but on this engineering challenge alone it was the speed with which the chip could wake up, transmit, and go back into an ultra-low-power sleep mode – as every millisecond counts – that contributed significantly towards us being able to achieve the one year battery life we were after from a CR2016 battery: what we believe to be an industry first for a Bluetooth low energy location tag.



This application is an example of a product that would simply have been impossible to develop technologically or commercially even two or three years ago, comments Geir Langeland, Nordic Semiconductor's Director of Sales & Marketing. I commend StickNFind for giving consumers a taste of the future of ultra low power wireless technology today and for the feat of engineering they achieved in managing to package all of this into a coin-sized Bluetooth low energy location tag so slim it looks like a sticker.