This sketch defines two variables: lowerThreshold and upperThreshold. These variables signify our thresholds. Non Call microwave-centered radar sensors have the ability to see as a result of small conductivity 'microwave-clear' (non-conductive) glass/plastic windows or vessel partitions by which the microwave beam is usually handed and measure a 'microwave reflective' (conductive) https://controltechme.com/ultrasonic-level-sensor/