Head Office for Tailor-Made and Baton-Zone Graduate Course, Toyohashi University of Technology, Toyohashi, Aichi, Japan.
Sensors (Basel). 2012;12(6):8338-54. doi: 10.3390/s120608338. Epub 2012 Jun 15.
Making several simultaneous measurements with different kinds of sensors at the same location in a solution is difficult because of crosstalk between the sensors. In addition, because the conditions at different locations in plant beds differ, in situ measurements in agriculture need to be done in small localized areas. We have fabricated a multimodal sensor on a small Si chip in which a pH sensor was integrated with electrical conductivity (EC) and temperature sensors. An ISFET with a Si(3)N(4) membrane was used for the pH sensor. For the EC sensor, the electrical conductivity between platinum electrodes was measured, and the temperature sensor was a p-n junction diode. These are some of the most important measurements required for controlling the conditions in plant beds. The multimodal sensor can be inserted into a plant bed for in situ monitoring. To confirm the absence of crosstalk between the sensors, we made simultaneous measurements of pH, EC, and temperature of a pH buffer solution in a plant bed. When the solution was diluted with hot or cold water, the real time measurements showed changes to the EC and temperature, but no change in pH. We also demonstrated that our sensor was capable of simultaneous in situ measurements in rock wool without being affected by crosstalk.
在溶液中的同一位置同时使用不同类型的传感器进行多次测量是困难的，因为传感器之间存在串扰。此外，由于植物床内不同位置的条件不同，农业中的原位测量需要在小的局部区域进行。我们在一个小的硅片上制造了一种多模态传感器，其中 pH 传感器与电导率（EC）和温度传感器集成在一起。用于 pH 传感器的是具有 Si(3)N(4)膜的 ISFET。对于 EC 传感器，测量了铂电极之间的电导率，而温度传感器是 p-n 结二极管。这些是控制植物床条件所需的最重要的测量之一。多模态传感器可以插入植物床中进行原位监测。为了确认传感器之间不存在串扰，我们在植物床中对 pH 缓冲溶液的 pH、EC 和温度进行了同时测量。当溶液用热水或冷水稀释时，实时测量显示 EC 和温度发生了变化，但 pH 没有变化。我们还证明了我们的传感器能够在岩棉中进行同时的原位测量，而不受串扰的影响。
