It may be minuscule, but there's a lens systems, light sensor, illuminator, electronics and more inside this sensing module, which Heptagon claims is the smallest in the world. Given that it's only 350 micrometers thick and has a surface area of 2mm², we're inclined to believe them.

To add some perspective, Heptagon's new module is four times thinner than a US one cent coin. Comparable products currently available are 40% thicker, the company adds. These unfathomably small dimensions were achieved using what Heptagon calls "wafer-level" miniaturisation technology, and form part of the company's efforts to create tiny system-in-a-package sensors for mobile and wearable devices.

Heptagon says that due to its size, the module is particularly suited for providing advanced contact and proximity sensing capabilities in "next-generation" mobile devices, in addition to providing concealed buttons that can be used in health monitoring systems and intelligent keyless access systems for things like car doors.

The module is in mass production already. While you'd think anything this small would be impossible to churn out in large quantities (surely you'd lose half of them?) Heptagon says it is able is able to develop its diddy module in high volumes and with very high yields thanks to a range of proprietary, patented wafer-level manufacturing methods.

Hartmut Rudmann, senior vice president of engineering at Heptagon, said: "We are excited to be taking our sensor technologies to an all-new level. By combining proprietary design and processes in solution development for these significantly thinner sensors, we're enabling greater design flexibility with reduced form factor and improved aesthetics for mobile and wearable devices seeking slimmer profiles, such as smart watches.

"It is now possible to spread out more sensors in a device to increase coverage or for a more accurate reading."