Bluetooth Low Energy is designed to enable devices with low power consumption. Several chipmakers including Cambridge Silicon Radio , Dialog Semiconductor , Nordic Semiconductor , STMicroelectronics , Cypress Semiconductor , and Texas Instruments have introduced their Bluetooth Low Energy optimized chipsets over the last few years. Devices with peripheral and central roles have different power requirements. A study by beacon software company, Aislelabs , reported that peripherals, such as proximity beacons, usually function for 1–2 years with a 1,000mAh coin cell battery.  This is possible because of power efficiency of Bluetooth Low Energy protocol which only transmits small packets as compared to Bluetooth Classic which is also suitable for audio and high bandwidth data.
The Romans are credited with the invention of the first smoke-free heating system in Western Europe: the hypocaust. Until recently, historians had assumed that its technology was largely lost after the collapse of the Roman Empire. In fact, however, it lived on in large parts of Europe, and was further developed into the “heat storage hypocaust”, an underground furnace on top of which granite stones would be piled, to then release hot air through vents in the floor. By this means, a room could be kept warm for days with just one firing of the hypocaust's furnace. Continue reading "Heat Storage Hypocausts: Air Heating in the Middle Ages" »