Gas concentration detection is important for applications such as gas leakage monitoring. Metal Oxide (MOx) sensors show high sensitivities for specific gases, which makes them particularly useful for such monitoring applications. However, how to efficiently sample and further process the sensor responses remains an open question. Here we propose a simple analog circuit design inspired by the spiking output of the mammalian olfactory bulb and by event-based vision sensors. Our circuit encodes the gas concentration in the time difference between the pulses of two separate pathways. We show that in the setting of controlled airflow-embedded gas injections, the time difference between the two generated pulses varies inversely with gas concentration, which is in agreement with the spike timing difference between tufted cells and mitral cells of the mammalian olfactory bulb. Encoding concentration information in analog spike timings may pave the way for rapid and efficient gas detection, and ultimately lead to data- and power-efficient monitoring devices to be deployed in uncontrolled and turbulent environments.

翻译：气体浓度检测在气体泄漏监测等应用中具有重要意义。金属氧化物（MOx）传感器对特定气体具有高灵敏度，使其特别适用于此类监测任务。然而，如何高效采样并进一步处理传感器响应仍是一个悬而未决的问题。受哺乳动物嗅球尖峰输出机制和事件驱动视觉传感器的启发，本文提出一种简洁的模拟电路设计方案。该电路通过两路独立通路脉冲间的时间差对气体浓度进行编码。研究表明，在受控气流嵌入气体注入的实验场景中，两路生成脉冲的时间差随气体浓度升高呈反比变化，这一现象与哺乳动物嗅球中簇状细胞和二尖细胞间尖峰时序差异的规律一致。利用模拟尖峰时序编码浓度信息，有望为快速高效的气体检测开辟新途径，并最终推动在非受控湍流环境中部署数据与功耗监测设备。