2-Photon Compatible Acoustic Plethysmograph

This acoustic plethysmograph was designed to able to function during 2-photon microscopy of mice in order to determine lung respiration volume. This project was turned open-sourced and the Arduino code and STL files are available on GitHub and Grabcad respectively.

Software & Hardware:
-Software
Multiple softwares were used to create and operate this device. The STL files of each piece were created with the use of Onshape and SolidWorks while 3DPrinterOS was used to print each of the individual pieces. For the use of the calibration device, a code was written in Arduino IDE, with the Adafruit stepper motor library, to allow for external inputs from LabVIEW to operate a stepper motor. For the recording of data, a custom VI was created in LabVIEW to receive and record the data from each individual component of the device, while MATLAB was used to analyze the recorded data. Finally, 3D Slicer was used to generate a 3-dimensional model of a mouse skull that was used to form fit the head piece that would connect to connect to the window of the vessel and restrain the mouse during imaging.
-Hardware
The 3D printer that was used to create the pieces was a Dremel 3D45 3D Printer set to 230°C nozzle temp, and 40°C bed temp, with PLA used as the filament. Layer thickness and shell thickness set to 0.3 and 0.4mm respectively. The stepper motor that was used was the Adafruit Stepper Motor Hybrid 12V (Adafruit Industries LLC.). This motor was controlled by the Arduino Uno (Arduino.cc) and the Adafruit Motor Shield V2 (Adafruit Industries LLC.). The speaker we used to output the sinewave was the Speaker 40HM 3W Top Port 76.5DB (PUI Audio Inc.) and was used to create a sine wave of 300 and 350Hz at an amplitude of 12V using a Siglent function generator (SDG1000X). Two Microphone Sensor High Sensitivity Sound Detection Modules (DEVMO) were used to detect relative sound pressures of the original signal and the excitation signal inside the vessel. A thermal camera (MLX90640 Thermal Camera 55 Degree, Pimoroni LTD.) was used to monitor intranasal temperature modulations for cross-validation of breathing measurements. Our vessel design was partially based off the equations of Catapane et al. paper(2) on Helmholtz resonators where we used the dimensions of the third Helmholtz resonator as the basis for of our vessel and neck, which were a cuboid and cylinder shape, respectively.