Overview of Status of Analysis, Design, Fabrication, Tests, etc.
By comparing and contrasting the measurement of the excessive projection of eye, the progress of several diseases can be analyzed. The distance that is to be measured using this device is the linear distance from the front of the cornea to a fixed position on the orbital bone, typically the lateral orbital rim or the frontal facial bones around the eye socket. The typical exophthalmometer that is widely being used throughout ophthalmology measures the clinical relationship of the globe to the orbit using prisms and mirrors. Every doctor uses the device slightly differently, and every patient has a dissimilar facial shape, forcing this device to a greater degree of possible error. The objective of this design project is to design and build a portable instrument capable of accurately measuring the distance between the cornea and the orbital rim.
Accomplishments from Previous Week
This project has multiple objectives and priorities. To achieve these objectives, we were able to brainstorm and produce a few solutions to this problem. The main objective and highest priority is to develop a device that can accurately measure the distance between the orbital bone and the very tip of the eye’s lens, the cornea, within an accuracy of 1 mm. If possible, they also expressed interest in having the device measure the distance between the two orbits across the face of the patient. They also touched on the possibility of having a picture taken from each side of the patients face for patient records.The sponsors also stressed many design constraints that helped narrow down what kind of product they desired. They requested that the product be lightweight and simple, allowing for easy and straightforward operation. They also wanted a standalone device over something that required a computer for data processing. With these constraints, we suggested a device that utilized a sensor on the inner side of the eye, near the nose, and a laser or infrared emitter on a horizontal slider. Once the sensor picked up the laser or infrared signal, the device would know that the slider had moved past the cornea, and the distance the slider had traveled could be calculated. This WOW design solution created a few more constraints, however. This design means that we must be careful about what type of sensing equipment we use to avoid damage to the eye.
Goals for Next Week
Risk Reduction Test: In the preliminary hardware test, the main objective is to use an Adriano in conjunction with light source and sensor to measure distances. The number one concern for the light source will be safety for the eye. Three light sources are under consideration; class 1 laser, infrared light, laser diode. The sensor used for testing purposes will be linear array light sensor. The electrics must be powered by the Adriano without the use of any external power source; such as, motor drives to boost voltage and current. To test the devise, a set distance will be marked on the light sensor and the output of the sensor will be displayed in the Adriano. The method of acquiring and interrupting the output of the sensor will be studied in this test.
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments
Research laser and sensor options
Learn the prexisting model and its problems via the reference sent through team email
Bring new ideas and concepts to brainstorm
Instructor Comments from Last Meeting and Actions Taken to Address these Comments
Index number (start ordering laser diode and linear sensors by this weekend)
Gain familiarity with the exophthalmometer - calculate grounds for systematic error (keep track of measurements everyday and compare the error and standard deviation)
Quantify the amount of systematic error: each person should come up with two ways
Hardware test as risk reduction
Accuracy
Amount of error expected and desired by the sponsor (250 microns -- 400% increase)
Smallest scale desired (1 mm)
Sources of systematic error
Risk Reduction / Hardware Test
Hardware test on both laser diode and linear sensor
Still widely explore optical methods (infrared and proximity sensors)
Upcoming Presentation & Write-ups
Include figures (include references; make own)
List and label with bullets
Literature search for different methods - divide up the team into (1) literature search & (2) hardware test groups
Risks and Areas of Concern
Eye safety, Choosing the optical light source, Accuracy on sensors
Resources or Information Required but not Available
Accuracy of each optical light source and sensors after linearly positioning the components
Schedule
Risk reduction hardware test to confirm the concerns
Progress on Report and Webpage
Problem definition worksheet filled and turned in
Start working and finalize on the powerpoint by next week