A pressure sensing assembly (1), comprising: an elongate, axially extending tube (100), having a flexible tube wall (102) that encloses an inner pressure chamber (106); and at least one sensor unit (200), including: two tube wall fixation devices (210), connected to the tube wall (102) at respective axially spaced apart positions, and configured to fix respective diameters (D, d) of the tube wall at said positions; and a first strain sensing element (220), connected to the tube wall (102) at a first position axially in between said two tube wall devices (210), and configured to provide a first signal indicative of an axial elongation of the tube wall resulting from a change in axial curvature of the tube wall when a pressure differential between the inner pressure chamber (106) and an outside environment (108) of the tube is applied across the tube wall at said first position.

An ascent rate indicator mechanism includes a first wheel set and a pressure sensor. The first wheel set is connected to the pressure sensor driven in rotation by a pressure variation. The mechanism further includes a second wheel set driven by the first wheel set in a single direction of rotation from a start position into a measurement position corresponding to a decrease in pressure, uncoupling and return structure to be actuated at regular intervals to uncouple the second wheel set and to return it to the start position, an ascent rate display mechanism connected to the second wheel set and including an indicator member arranged to occupy, at each regular interval, a display position representative of the decrease in pressure during the interval, and synchronization structure actuated at each regular interval and arranged to maintain the display position of the indicator member during the regular interval.

Systems and methods for detecting pressure changes is provided. A system can include an object having a surface. The system can include a coating having microcapsules. The coating can be a pressure-sensitive paint configured to emit fluorescence outside of a threshold pressure. The coating can adhere to the surface of the object and receive an application of a pressure from a source. The coating can change at least a portion of the microcapsules from a first state to a second state responsive to the application of the pressure meeting a threshold pressure. The system can include an image capture device configured to capture images of the coating to identify a change in pressure at a portion of the object.

A remotely interrogatable pressure transition indicator (100) having a pressure sensitive element (110) interacting with a remotely interrogatable mechanical switch (120). The pressure sensitive element (110) is a hermetically sealed, gas impermeable, flexible walled sachet (110) containing a quantity of gas, operable for transitioning between inflated and deflated conditions induced by a change in external gaseous pressure experienced by the sachet (110). The sachet (110) interacts with the mechanical switch (120) to producing a first interrogatable value when the sachet (110) is inflated and a second interrogatable value when the sachet (110) is deflated.