CEOT-Center for Electronics, Optoelectronics and Telecommunications, University of Algarve, Campus Gambelas, 8005-139 Faro, Portugal.
Department of Physics, University of Algarve, Campus Gambelas, 8005-139 Faro, Portugal.
Sensors (Basel). 2022 Mar 14;22(6):2227. doi: 10.3390/s22062227.
An ultra-low-cost RCL meter, aimed at IoT applications, was developed, and was used to measure electrical components based on standard techniques without the need of additional electronics beyond the AVR® micro-controller hardware itself and high-level routines. The models and pseudo-routines required to measure admittance parameters are described, and a benchmark between the ATmega328P and ATmega32U4 AVR® micro-controllers was performed to validate the resistance and capacitance measurements. Both ATmega328P and ATmega32U4 micro-controllers could measure isolated resistances from 0.5 Ω to 80 MΩ and capacitances from 100 fF to 4.7 mF. Inductance measurements are estimated at between 0.2 mH to 1.5 H. The accuracy and range of the measurements of series and parallel RC networks are demonstrated. The relative accuracy (ar) and relative precision (pr) of the measurements were quantified. For the resistance measurements, typically ar, pr < 10% in the interval 100 Ω−100 MΩ. For the capacitance, measured in one of the modes (fast mode), ar < 20% and pr < 5% in the range 100 fF−10 nF, while for the other mode (transient mode), typically ar < 20% in the range 10 nF−10 mF and pr < 5% for 100 pF−10 mF. ar falls below 5% in some sub-ranges. The combination of the two capacitance modes allows for measurements in the range 100 fF−10 mF (11 orders of magnitude) with ar < 20%. Possible applications include the sensing of impedimetric sensor arrays targeted for wearable and in-body bioelectronics, smart agriculture, and smart cities, while complying with small form factor and low cost.
开发了一款超低成本的 RCL 表，旨在满足物联网应用的需求。它采用基于标准技术的测量方法，无需额外的电子设备，仅使用 AVR®微控制器硬件本身和高级例程。本文描述了测量导纳参数所需的模型和伪例程，并对 ATmega328P 和 ATmega32U4 AVR®微控制器进行了基准测试，以验证其电阻和电容测量的准确性。两款 ATmega328P 和 ATmega32U4 微控制器均能够测量 0.5 Ω 至 80 MΩ 的隔离电阻和 100 fF 至 4.7 mF 的电容。电感测量范围估计在 0.2 mH 至 1.5 H 之间。本文还演示了串联和并联 RC 网络的测量精度和范围。本文还对测量的相对精度（ar）和相对精度（pr）进行了量化。对于电阻测量，通常在 100 Ω 至 100 MΩ 的范围内，ar、pr < 10%。对于电容测量，在一种模式（快速模式）下，ar < 20%，pr < 5%，在 100 fF 至 10 nF 的范围内，而在另一种模式（瞬变模式）下，通常在 10 nF 至 10 mF 的范围内，ar < 20%，pr < 5%，在 100 pF 至 10 mF 的范围内。在一些子范围内，ar 低于 5%。两种电容模式的结合可实现 100 fF 至 10 mF（11 个数量级）的测量范围，ar < 20%。可能的应用包括针对可穿戴和体内生物电子学的阻抗传感器阵列的感应、智能农业和智能城市，同时符合小尺寸和低成本的要求。
