I whakawhanakehia e te Firessentor tetahi otinga inenga wai wai i te hinu, e whakamahia ana me o maatau umanga ultrasonic.
Ko te sensor o te taupoki Manhole (te aroturuki taumata o te taumata ultrasonic) ka uru ki te hangarau ultrasonic, te hangarau whakawhitiwhiti a te NB-iot me te 2.4G hangarau whakawhitiwhiti korero 2.