The 'Tempo' from U.K. startup Blue Maestro is encased in a sleek, highly polished polycarbonate pebble-shaped casing designed to look and feel like a high quality ornament. It employs a Nordic Semiconductor nRF51822 SoC, utilizing its high output power and ultra low power operation to offer a maximum 250-ft (75m) operating range and one-year battery life from a pair of regular AA batteries.
In operation, the weather- and water-proof Tempo takes full advantage of the embedded Nordic nRF51822 SoC high +4dB maximum output power to maximize operating range to up to 250-ft (75m) – including through walls and floors (which will, however, reduce the range depending on construction material) – while still achieving a one-year continuous use operating life from a pair of regular, user- replaceable, AA batteries due to the ultra low power operating characteristics of the nRF51822.
Each Tempo advertises the current temperature once every two seconds and records temperature in its memory once an hour over the previous 24 hours so users not-in-range can track the temperature behavior when they are next in range through a free Android or iOS app. The app will provide alerts at pre-set temperature thresholds, even when running in the background. And Blue Maestro claims there is no (for practical purposes) upper limit to the number of Tempos that can be operated simultaneously and that the product requires no set-up beyond downloading the app.
Temperature is measured using a high accuracy thermistor that monitors air or water temperature (rather than less accurate casing temperature) in the immediate vicinity of the Tempo to allow even subtle variations to within ±0.2oC to be immediately detected. Readings can also be 'read' out loud for the visually-impaired.
More information on Nordic's nRF51822 SoC
More information on Blue Maestro’s Tempo