Sensing on a Zero Power Budget

　　簡(jiǎn)化物聯(lián)網(wǎng)傳感器

　　在任何時(shí)候，大部分的物聯(lián)網(wǎng)都可能無(wú)所作為。物聯(lián)網(wǎng)傳感器通常只需要在很短的間隔內(nèi)進(jìn)行測(cè)量，然后將產(chǎn)生的少量數(shù)據(jù)送回收集器，然后返回盡可能少的電量，直到下一次測(cè)量為止。一些智能傳感器可以由一個(gè)小電池供電，并在幾年內(nèi)不用充電或更換。

　　如果完全可以避免永久連接電源的需求，傳感器可以無(wú)限期地部署，并且可以變得更小、更輕。這為新類(lèi)型的傳感器創(chuàng)造了機(jī)會(huì)，例如可以佩戴舒適的無(wú)損傷醫(yī)用傳感器。附著在皮膚上的無(wú)線(xiàn)溫度感應(yīng)貼片，可以快速檢查，使佩戴者比有線(xiàn)傳感器更能自由移動(dòng)。與可重復(fù)使用的含鉛傳感器相比，一次性貼片也有衛(wèi)生效益。

　　許多其他應(yīng)用程序可以受益于粘貼傳感器補(bǔ)丁，如監(jiān)測(cè)溫度，濕度或壓力。它們還可用于占用檢測(cè)、工業(yè)過(guò)程無(wú)連接監(jiān)控或智能農(nóng)業(yè)，如監(jiān)測(cè)土壤或溫室環(huán)境，或檢查牲畜的體溫。

　　A new category of smart sensors is emerging that combine an ultra-low-power sensor with RFID technology. These sensors can be powered by the energy in the RF field emitted by the RFID reader only for the time required to take a reading. Batteryless sensors such as these collect data and forward it to the reader only on demand， and do not take measurements or store data independently.

　　Figure 1 presents a simplified overview of the functional blocks of a passive patch sensor， including the front-end interface to an analog or digital transducer， signal conditioning， data processing， wireless communication， and power management. Integrating these various elements to create a system capable of operating with the limited available RF field energy demands skilled low-power design， with careful attention to computational load and efficient power management. Such a sensor must also be small and flexible for easy positioning， and comfortable if it is to be a wearable device such as a bio sensor.