Thin film-based thermal flow sensors
afford applications in healthcare
and industries owing to their merits in preserving initial flow distributions.
However, traditional thermal flow sensors are primarily applied to
track flow intensities based on hot-wire or hot-film sensing mechanisms
due to their relatively facile device configurations and fabrication
strategies. Herein, a calorimetric thermal flow sensor is proposed
based on laser direct writing to form laser-induced graphene as heaters
and temperature sensors, resulting in monitoring both flow intensities
and orientations. Via homogeneously surrounding spiral heaters with
multiple temperature sensors, the device exhibits high sensitivity
(∼162 K·s/m) at small flows with an extended flow detection
range (∼25 m/s). Integrating the device with a data-acquisition
board and a dual-mode graphical user interface enables wirelessly
and dynamically monitoring respiration and the motion of robotic arms.
This versatile flow sensor with facile manufacturing affords potentials
in health inspection, remote monitoring, and studying hydrodynamics.