Bhakta Heran C, Choday Vamsi K, Grover William H
Department of Bioengineering, University of California, Riverside, 900 University Ave., Riverside, California 92521, United States.
ACS Omega. 2018 Sep 30;3(9):11026-11032. doi: 10.1021/acsomega.8b01673. Epub 2018 Sep 12.
The frequencies of notes made by a musical instrument are determined by the physical properties of the instrument. Consequently, by measuring the frequency of a note, one can infer information about the instrument's physical properties. In this work, we show that by modifying a musical instrument to contain a sample and analyzing the instrument's pitch, we can make precision measurements of the physical properties of the sample. We used the mbira, a 3000-year-old African musical instrument that consists of metal tines attached to a wooden board; these tines are plucked to play musical notes. By replacing the mbira's tines with bent steel tubing, filling the tubing with a sample, using a smartphone to record the sound while plucking the tubing, and measuring the frequency of the sound using a free software tool on our website, we can measure the density of the sample with a resolution of about 0.012 g/mL. Unlike existing tools for measuring density, the mbira sensor can be made and used by virtually anyone in the world. To demonstrate the mbira sensor's capabilities, we used it to successfully distinguish diethylene glycol and glycerol, two similar chemicals that are sometimes mistaken for each other in pharmaceutical manufacturing (leading to hundreds of deaths). We also show that consumers could use mbira sensors to detect counterfeit and adulterated medications (which represent around 10% of all medications in low- and middle-income countries). We expect that many other musical instruments can function as sensors and find important and lifesaving applications.
乐器发出的音符频率由乐器的物理特性决定。因此，通过测量音符的频率，人们可以推断出有关乐器物理特性的信息。在这项工作中，我们表明，通过对乐器进行改造以包含一个样本并分析乐器的音高，我们可以对样本的物理特性进行精确测量。我们使用了姆比拉，一种有3000年历史的非洲乐器，它由附在木板上的金属尖齿组成；拨动这些尖齿就能演奏出音符。通过用弯曲的钢管替换姆比拉的尖齿，在钢管中填充样本，用智能手机在拨动钢管时录制声音，并使用我们网站上的免费软件工具测量声音的频率，我们可以以约0.012 g/mL的分辨率测量样本的密度。与现有的密度测量工具不同，姆比拉传感器几乎可以由世界上任何人制造和使用。为了展示姆比拉传感器的能力，我们用它成功地区分了二甘醇和甘油，这两种相似的化学物质在制药生产中有时会被彼此误认（导致数百人死亡）。我们还表明，消费者可以使用姆比拉传感器来检测假冒和掺假药物（在低收入和中等收入国家，这类药物约占所有药物的10%）。我们预计，许多其他乐器也可以用作传感器，并找到重要的救命应用。
