Overview
This is a training model for nurses and medical students to use to practice taking a cast saw off of an 8-year-old child. This model was created to be reusable and provide instant feedback if the user touches the patient with the cast saw. This model will help train future students to not burn the child as they take off the cast.
Before I started to create the model, I needed to create a mechanism that would determine whether the user has cut too deep. The previous person on the project had experimented with temperature sensors that would determine if the surface of the skin got too high. While this type of sensor would be ideal, creating a flexible temperature sensor that is reusable was a difficult challenge. I experimented further with this method by embedding thermistors and flexible tape thermocouples in silicone. However, this method did not work since the silicone was not conductive enough for the sensors to have an accurate measurement.
I next experimented on a visual method. This would have consisted of wax that would melt around the temperature that skin burned. The wax would be scented so once melted, would give off an odor which the user will notice. Through testing it seemed that the response time was too slow, and the scent was not noticeable enough.
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In the final method, I decided to use a similar mechanism seen in the game Operation. Since the cast saw is made of a conductive material, it would transfer current when part of a circuit. So, by making the surface of the model conductive, the saw can set off an alarm if it were to come into contact with the model.
To create the model, I used an online arm model of an 8-year-old child to create a 3D printed mold. To strengthen the model, I added bamboo dowels that would function as bones. I made holders for the dowels so they would be held in the correct position as the silicone would cure in the molds (see image below).
Once the arm was made, I covered the surface of the model with copper tape. I used copper tape since it was flexible, conductive, and easily replaceable. I then connected the circuit onto the copper tape and then cast the arm.
The model was tested and lite an LED bulb when the saw was in contact with the arm. The model satisfied its requirements and can be easily reproduced.