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University of California, San Diego
Mechanical and Aerospace Engineering
SP25 MAE 156B: Senior Design Project
Neha Jacob, Gina Arce, Cassie Pheiffer, Sohan Lele
Sponser: Blake Iwaisako from SoundImaging
Project Background
MRI procedures can be uncomfortable for patients because they are very loud and can cause claustrophobia. SoundImaging has developed a pneumatic headphone system that allows patients to listen to their preferred audio input while dampening the sound of the MRI machine, making the procedures more comfortable.
Objective
Objective
Our goal in MAE 156B is to improve the design of an existing pneumatic headphone system that allows patients to listen to audio during MRI procedures. The system must deliver quality audio the patient can hear and understand during the procedure. Furthermore, it must have noise-dampening attributes that diminish the MRI sounds.
Requirements
Requirements
Subjective and quantitative increase in audio quality through the headphones
Quantitative increase in audio decibel level through the headphones
MRI noise must be reduced to a comfortable level for the user
Space constraint to fit inside the smallest area of an MRI, the head coil, and must be compatible with multiple types of MRI machines
Design must use non-ferrous or shielded materials
Headphone system cannot interfere with MRI images
Only one power/audio cable connected to the headphone system can be used
User friendly and durable design
Prototyping
Prototyping
Experimentation was conducted in an anechoic chamber to isolate sound measurements for precise recording, simulating MRI noise using a speaker reaching 119.733 dB. A laptop-amplifier-speaker system delivered sound through pneumatic tubing to a headset on a mannequin with a microphone. Testing focused on refining the transducer shape and material, tubing characteristics, and headphone noise dampening through iterative prototyping and data collection.
Resulting Design Solution
Resulting Design Solution
Our final prototype is a fully MRI-compatible pneumatic headphone system consisting of three optimized components:
Headphones: ABS plastic outperformed other plastics in durability and FDA compatibility. A high-density foam lining and recycled denim insulation on the outside allow for ample noise dampening and acoustic clarity. For improved comfort, an adjustable headband that maintains a snug fit for effective acoustic sealing.
Transducer: Functionally, this component converts electrical signals to air pressure waves that carry the audio through tubing. ABS with 15% infill allows smoother sound transmission. A smooth, curved profile inside the dome outperformed the stair-step profile domes in decibel output.
Pneumatic Tubing: Polyvinyl Chloride (PVC) tubing with 1.25 in outer diameter provides rigid, kink-resistant support as well as superior sound clarity over long distances
Copy of Week 9_ Preliminary Design Review (Team 5-SoundImaging MRI).pdfCopy of Week 10: Team 5 Poster - Final.pptxPage updated
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