Abstract: A transducer for measuring the thickness of ice in a body of water includes a transducer body, at least one ice presence sensor for measuring the presence of ice at a point beyond a boundary layer between the transducer body and the body of water, a flotation element, a controller, and a display assembly. The transducer body includes waterproof membrane sealed orifices positioned on the transducer body for one or more ice presence sensors. A tether point attaches an anchor to keep the transducer at a fixed location in the water body. The ice presence sensor includes a sense probe passing through the waterproof membrane, a sense probe seal, a drive rod, a switch, and an actuator. The display includes one or more visible elements to indicate ice thickness at the transducer location. The ice thickness is inferred by the collective indications at the one or more ice presence sensors.

Abstract: A transducer for measuring the thickness of ice in a body of water includes a transducer body, at least one ice presence sensor for measuring the presence of ice at a point beyond a boundary layer between the transducer body and the body of water, a flotation element, a controller, and a display assembly. The transducer body includes waterproof membrane sealed orifices positioned on the transducer body for one or more ice presence sensors. A tether point attaches an anchor to keep the transducer at a fixed location in the water body. The ice presence sensor includes a sense probe passing through the waterproof membrane, a sense probe seal, a drive rod, a switch, and an actuator. The display includes one or more visible elements to indicate ice thickness at the transducer location. The ice thickness is inferred by the collective indications at the one or more ice presence sensors.

Abstract: An RTD having a thin film HfN resistor formed on a substrate for temperature detection in accordance with the resistance of the HfN resistor. The RTD is a two lead device having high accuracy and a wide temperature range from 20 to 1400 degrees Kelvin. The substrate has bonding pads or contact strips connected to the resistor and processing electronics. An SiN thin film passivation layer is formed on the resistor and substrate. Two leads connect the bonding pads or contact strips to processing electronics and an indicator.