EPICS PURDUE SPRING 2021
Sláinte
Need Statement
“The need to create an affordable, in-clinic, non-intrusive and user friendly device for an individual with limited mobility to help motivate them to track their waist circumference in support of their cardiovascular health.”
Sláinte is designing a medical device that will be used by obese individuals in Ireland to measure waist circumference. The device will be a waist circumference measuring device that can be used by an individual without assistance. The device will be designed to not only be used in a clinical setting but preferably be used at home. The hope is for the device to encourage and motivate the individuals to keep track of their measurements and work towards a healthier cardiovascular life.
Currently, when measuring the waist circumference, a dietitian must use a measuring tape and wrap it around the patient. This process of measuring can be intrusive of the patient and make them feel uncomfortable with themselves. Our project is working towards making this measurement process non-invasive and user friendly so that the patients will be encouraged to keep working towards their goal.
Sláinte is partnered with Croí House, a nonprofit organization in Galway, Ireland. We are partnered with the Clann Program which is an obesity management program. It is a healthy lifestyle initiative that aims to help individuals achieve a healthy weight and shape through physical activity and healthy eating.
Some of the main issues that the Clann Program is facing are that their patients have limited mobility, so multiple doctors are needed to measure their waists and this can feel intrusive and alienating.
The project began in May 2014 and was brought to Croí House in Ireland three separate times. It started as a device that could be used at a user´s home but it was later decided that it would be beneficial to be implemented in clinics as well. Previous prototypes were finished in 2019 and Spring 2020 but did not function properly and so the Fall 2020 team decided to take the project in a new direction.
In previous designs, teams have used a physical measuring tape and potentiometer to obtain measurements, but this design ran into some issues -- one such issue being that the potentiometer would often slip, resulting in an inaccurate measurement. The tautness of the tape measure also made it difficult to get an accurate measurement.
To fix these errors, the team from Spring 2020 came up with ideas for modifications that they and future teams could make to solve these issues but the Fall 2020 team realized that these changes would increase the complexity and probability of failure for the device.
Because of these reasons, the Fall 2020 team has decided to develop a new design for a device that is accurate and provides the user with a positive experience.
Updates
Fall 2020
September 2020
We are currently taking the project in a new direction. While previous iterations provided an adequate seeming start, the proposed modifications would have led to an extremely complex and costly product. It’s for these reasons that we decided to reevaluate our design considerations and bring the project in a new direction. The goal of this semester is to produce a functioning product that can be further optimized. This optimization should only deal with motor control and sensor readings, no large mechanical subsystems should need to be redeveloped after this semester.
After looking at past semesters and the design updates they proposed, it was decided to take the project in a new direction. The team’s main priority is to make headway on our new design. This will require timely phases of design, manufacture, and testing. We are confident that the current design will prove effective and, with further optimization and development, can fulfill all requirements proposed by our partner.
October 2020
We have begun working with the ultrasonic range meter sensor and have taken and recorded measurements in Microsoft Excel. We took measurements first with a notebook and then our hands (one stacked on top of the other to provide more surface area). We took measurements at 5 centimeter increments, starting with 5 centimeters and going to 100 centimeters. We then calculated the differences between the actual and expected values and then calculated the percent error using the percent error formula [(actual value observed - expected value)/(expected value) x 100].
Development has also begun with motor control algorithms and layouts. We currently have the motor setup tethered to a laptop and external power supply for testing purposes. This will most likely be the case until we can more formally prove functionality. Currently we have control over the motor’s speed and direction, and are working on implementing a limit switch system to indicate when we are at the end of the track. While the limit switch system isn’t strictly necessary, it increases the robustness of the design and decreases any potential risk of failure. In the coming weeks, we are looking to manufacture the linear track and implement the motor to test it’s capabilities.
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November 2020
We began working with the ultrasonic range meter sensor and took/recorded measurements in Microsoft Excel. We took measurements first with a notebook and then our hands. We took measurements at 5 centimeter increments, starting with 5 centimeters and going to 100 centimeters. We then calculated the differences between the actual and expected values and then calculated the percent error using the percent error formula. Development has also begun with motor control algorithms and layouts. We currently have the motor setup tethered to a laptop and external power supply for testing purposes. This will most likely be the case until we can more formally prove functionality. Currently we have control over the motor’s speed and direction, and are working on implementing a limit switch system to indicate when we are at the end of the track. While the limit switch system isn’t strictly necessary, it increases the robustness of the design/decreases any potential risk of failure. In the coming weeks, we are looking to manufacture the linear track and implement the motor to test it’s capabilities.
We took measurements with our prototype which consists of the basic linear track with the stepper motor, sensor, breadboard, wires, button, and Arduino. A wooden board was held at varying distances from the sensor and at various angles. Data was recorded in Excel to be analyzed and interpreted later.
The design review happened on Wednesday, 2 December and was a success! We had two design reviewers from Shell and Caterpillar and they asked us several questions and helped us to think about possibly changing the type of sensor that we are using. They asked us how long it will take for the device to take a measurement of the waist of an individual. It should take approximately twenty to thirty seconds overall. It will probably take ten to fifteen seconds to scan the front but then the individual needs to turn around for it to measure the back part of his/her waist as well. The time efficiency of this device is a concern because an obese individual may have difficulty standing for very long.
