Wind dispersal of battery-free wireless devices
Wind dispersal of battery-free wireless devices
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DOI：
10.1038/s41586-021-04363-9
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发表时间：
2022-03-16
期刊：
影响因子：
64.8
通讯作者：
Gollakota, Shyamnath
中科院分区：
文献类型：
--
作者：
Iyer, Vikram;Gaensbauer, Hans;Gollakota, Shyamnath
植物覆盖了地球陆地的很大一部分，尽管大多数物种的移动性有限甚至没有。为了运输繁殖体，许多植物进化出了利用风传播种子的机制（1-4）。例如，蒲公英的种子有一根刚毛状的细丝结构，它可以降低种子的终端速度，帮助种子在向地面飘移时定位。受此启发，我们展示了无电池无线传感设备的风扩散。我们的毫米级设备重量为30毫克，采用可编程的现成部件设计在灵活的基板上，以实现各种传感和计算应用的可扩展性和灵活性。该系统使用轻型太阳能电池和能量收集电路供电，该电路在低光和可变光条件下都具有鲁棒性，并具有支持数据传输的反向散射通信链路。为了实现太阳能收集所需的大面积分散和垂直着陆，我们开发了蒲公英启发的薄膜多孔结构，其终端速度达到0.87 +/- 0.02米/秒，垂直着陆概率超过95%，具有空气动力学稳定性。我们在室外环境中的研究结果表明，这些设备可以在微风中行驶50-100米。最后，在自然系统中，单个种子形态的差异导致一些种子落得更近，而另一些种子走得更远。我们采用了类似的方法，并展示了如何调节结构的孔隙度和直径，以实现跨设备的分散变化。
Plants cover a large fraction of the Earth's land mass despite most species having limited to no mobility. To transport their propagules, many plants have evolved mechanisms to disperse their seeds using the wind(1-4). A dandelion seed, for example, has a bristly filament structure that decreases its terminal velocity and helps orient the seed as it wafts to the ground(5). Inspired by this, we demonstrate wind dispersal of battery-free wireless sensing devices. Our millimetre-scale devices weigh 30 milligrams and are designed on a flexible substrate using programmable, off-the-shelf parts to enable scalability and flexibility for various sensing and computing applications. The system is powered using lightweight solar cells and an energy harvesting circuit that is robust to low and variable light conditions, and has a backscatter communication link that enables data transmission. To achieve the wide-area dispersal and upright landing that is necessary for solar power harvesting, we developed dandelion-inspired, thin-film porous structures that achieve a terminal velocity of 0.87 +/- 0.02 metres per second and aerodynamic stability with a probability of upright landing of over 95%. Our results in outdoor environments demonstrate that these devices can travel 50-100 metres in gentle to moderate breeze. Finally, in natural systems, variance in individual seed morphology causes some seeds to fall closer and others to travel farther. We adopt a similar approach and show how we can modulate the porosity and diameter of the structures to achieve dispersal variation across devices.