Otoscope
For the final project of the UC Davis CAD course, I was teamed up with four classmates to create part, assembly, and drawing files within SolidWorks to make an otoscope. The otoscope’s performance was evaluated by using SolidWorks Simulation to perform test analysis.
Project Overview and Design Limitations
An otoscope is used to examine the ear during physical examinations. The device illuminates and magnifies the ear canal and eardrum. The condition of the ear is evaluated by examining the lymphatic membrane.
However, an undercharged otoscope will produce poor light and can result in a yellow tint to the lympanic membrane. The inaccurate appearance of color can cause misinterpretation of the ear health during examinations and lead to misdiagnosis.
Anatomy of the Ear
Otoscope Demonstration
Final Product
Isometric View
Exploded View
To prevent misdiagnosis of ear health from an undercharged otoscope, our team decided to integrate a user feedback system into our design.
By connecting the circuitry of the lightbulb with two visible LED lights at the bottom of the handle, a signal can be given to indicate when the battery levels are acceptable and when they are too low. A green light is used to signal a fully charged battery and a red light is used to indicated that the battery needs to be replaced.
Exploded View Animation
Left View
Top View
Bottom View
Right View
Front and Back View
Otoscope Parts
The otoscope consists of six mechanical parts shown below. The parts include the head, handle, ear tip, lens frame, lens glass, and bulb. To complete the project efficiently, each team member was responsible for designing a part. I was responsible for completing the head of the otoscope.
Lens Frame
Lens
Ear Tip
Handle
Head
Bulb
Head Design
Head
Head Drawing
The head connects all the parts of the otoscope together. The front of the head has a small circular cut out design to press fit the lens frame. The back of the head is also designed as a press fit to allow the ear tips to attach and detach easily. The head is also hollow to allow the light to reflect into the ear tip from inside the handle. After considering the ergonomics of users during the examination procedure, I designed the head to slope downwards at a 120 degree angle. This would provide a better user experience and improve the examination outcomes.
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Drop Test
The drop test of the otoscope was performed on SolidWorks Simulation. The otoscope was dropped on its side at a height of 4.5 feet based on the approximate height the otoscope would be held at during use. The otoscope was dropped at the speed of gravity, 9.8 m/sec^2.
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Based on the drop test, there is higher stress on point on the side of the head. This is expected since the side of the head hits the ground first. However, aside from that point, the stress is evenly distributed throughout the otoscope.
Drop Test Set-up
Drop Test Results
Static Grip Test
Grip Test Set-up
Grip Test Setup
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The static grip test was performed on SolidWorks Simulation. The average force a human being exerts on an object of this size is approximately 489 N, therefore we used that value of force for the test.
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Based on the static grip test, the only region of failure is near the ear tip attachment of the head. We tried to change the material of the head to a stronger metal but this did not reduce the point of failure. After further examination, I believe the failure was caused by an uneven distribution of weight at the base of the head. To solve this problem, redesigning the head with a ncreasing thdiameter and width of the head's base could provide better support to the head and reduce the stress in that area.
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Project Overview
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This project was my first introduction to SolidWorks and it was on of my favorite classes at UC Davis. I picked up on SolidWorks and 3D design quickly because I enjoyed it so much. I enjoyed designing the head of the otoscope because I had the opportunity to be creative and think about the user and the otoscope ergonomically. This project allowed me to see my potential with CAD and user experience.
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If you would like to learn more about the project, please see the link below.
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