P2: Digital 3D Model Process Blog

Context:

For the class HCDE 451, the assignment was to create a digital prototype of a wearable IoT device in the CAD software, OnShape. My model built off a previous physical prototype of a TENS unit for menstrual pain.

Design:

Like for the Analog 3D model, the intended users were people who suffered from period cramps. The purpose was to reduce menstrual pain by using electrodes to stop pain signals from going to the brain. The functionality of this device is that a user plugs in a USB-like cable into the main TENS unit. The cable comes with attached gel stickers meant to be placed on the area where the user feels pain. The user then turns on the device and can adjust their level of pain relief. Once the user turns off the device, the data is sent to an app on the user’s phone for them to see.

The feasibility of this design to make in CAD is definitely possible. Below is an incomplete model of my digital prototype. I had never used OnShape before and the last time I used CAD software was SolidWorks in 2017. For this specific assignment, I wasn’t sure how to design the cable with the gel stickers, so they were not included in the drafts and finalized versions of the prototype.

One of my first renders for TENSy

Prototype:

This prototype is a less clunky version of the Analog 3D model. There are more curved edges and surfaces than the previous model which was boxier.

Steps for Finalized Prototype:

1. Started with a circle sketch because I wanted to eventually make a cylindrical shape.
2. I then extruded the circle sketch to create a cylinder of 75 mm in height. In the original version, the cylinder was smaller in height. However, after doing some research on the dimensions of popular TENS menstrual devices, Ovira and Livia, I decided to make the cylindrical shape taller.
3. On top of the cylinder on the front plane, I sketched a rectangle.
4. I then extruded the rectangle 15 mm as “remove” to create an outlet for the electrode USB cable.
5. I used the transform tool to move my extruded rectangle closer to the center of the circle because I wanted to make the top more round to match the bottom.
6. I used the fillet tool on the edge of extrude 1 with a circular radius of 9 mm. This was to even out the shape of the device.
7. Next, I used the fillet tool on the edge of the first extrude to get a rounder and smoother bottom of the device. This would ideally make it easier to place in a user’s pocket if they wished. Additionally, The fillet radius is 15 mm which is in between too round to stand up straight on its own and too clunky to fit into a pocket.
8. I then sketched another circle on the top plane of the cylindrical shape to create a power button for the device.
9. I extruded this circle outward by 21 mm from the center of the cylindrical shape so the button is pushable.
10. I added another plane so that I could work on the clip-on part of the device
11. Next, I sketched an ellipse to act as a clip/hook to attach TENSy onto pants.
12. For the final version, I used the fill tool to fill in the hook. I wanted to make it look like this elliptical shape could move outwards, similar to a clip, but I couldn’t figure out how to do it in OnShape.

Below are images of the TENSy render before classroom feedback

Here is a side view of TENSy that shows the back attempted clip-on, the USB slot, and the power button.

Here is a top view of the original TENSy render mainly focusing on the rectangular extrusion.

Below are after the class critique:

Here is the newer render of TENSy. This is the front view with the power button in a darker teal color for emphasis that a user should push it.

This is the side view of the new TENSy render. I was able to use fill to fill in the back clip-on.

Analysis:

During this process, I learned that you can change the colors of the different parts. By going near the cube shape next to the cube with the axes. I don’t remember the steps where I added the colors.

For next time, I would try harder to figure out how to make the back of the TENSy device to be attachable to clothing. For the life of me, I couldn’t figure it out. Ideally, I would like to learn how to make a part for the back of the device, similar to how Ovira and Livia do it as shown below:

Additionally, I did do some research on dimensions for current TENS devices to change the dimensions of my own prototype. However, I feel like I should have done research on the dimensions of existing TENS devices before I started prototyping in OnShape.

I would also like to learn how to make USB cables in OnShape to show the cable with electrodes that would plug into the rectangular extrusion. I wasn’t sure how to make a USB cable in OnShape and wasn’t sure if I should have included it in my render.

Near the end of my render, I realized I never added plus or minus buttons to my render as I did in my analog 3D model. However, I realized while looking at the Livia device that users do not have a way to keep track of the power levels on the device. With this in mind, I thought about perhaps allowing users to change the power levels through an app on their phones, similar to how certain IoT light bulbs can change intensity through apps.