This paper suggests a portable multi-gas sensing module with chemiresistive gas sensors on a micro-electro-mechanical-systems (MEMS)-based heating platform. MEMS gas sensors are composed of four microheaters mounting heterogeneous sensing nanomaterials (SnO₂ nanotubes and ZnO nanowires with/without a Pt catalyst) and operating power is only 6 mW per each heater. A comprehensive approach to control heaters and readout multiple resistive sensors is implemented on a printed circuit board through the combination of analog/digital signal processing and a highly reconfigurable circuit structure. A wide range of sensor resistance (1 kΩ-100 MΩ) can be read with a relative error less than 1% by adaptively adjusting the gain of a trans-impedance amplifier. Heater controller circuits are operated in a way to give optimized power for each heater, and the target power is maintained at a constant value to keep a stable temperature condition. The module’s multiple gas sensing capability enables selectivity enhancement by principle component analysis (PCA). Operation mode is readily reprogrammed to give repetitive sleep mode, and it is demonstrated that fabricated sensors show decent response and recovery to frequent heater on/off repetition. For both of portable and stationary applications, Bluetooth Low Energy and Wi-Fi communication is realized through a RF-microcontroller combination system-on-chip (SoC).

本文提出了一种在基于微机电系统（MEMS）的加热平台上具有化学阻性气体传感器的便携式多气体传感模块。MEMS气体传感器由四个装有异质感测纳米材料（SnO ₂带有/不带有Pt催化剂的碳纳米管和ZnO纳米线），每个加热器的工作功率仅为6 mW。通过模拟/数字信号处理和高度可重构的电路结构的组合，在印刷电路板上实现了一种控制加热器和读出多个电阻式传感器的综合方法。通过自适应地调节跨阻放大器的增益，可以以相对小于1％的相对误差读取大范围的传感器电阻（1kΩ-100MΩ）。加热器控制器电路的工作方式是为每个加热器提供优化的功率，目标功率保持在恒定值以保持稳定的温度条件。该模块的多种气体传感功能可通过主成分分析（PCA）增强选择性。操作模式易于重新编程以提供重复的睡眠模式，并且证明了制造的传感器对频繁的加热器开/关重复显示出良好的响应和恢复能力。对于便携式和固定式应用，低功耗蓝牙和Wi-Fi通信都是通过RF微控制器片上系统（SoC）组合实现的。