3D-printed Wearable Button
Building and designing a 3D printed button and wearable
This week, our paper bag contained three items: copper tape, a battery, and a LED pin. Our prompt? To use our 3D printers and create a wearable that lit up an LED as a button was pressed. The task seemed simple, but there was a twist — we would have to create our own button, and design our wearable such that it would be easy to replace and remove the battery.
Materials given:
- Copper tape
- 3V Lithium Coin Battery
- LED
The Prompt:
A 3D printed wearable that lights up an LED with a push of a button.
Our End Result:
Designing our Button
Our first step was designing our button. We had many ideas on how to do this — and they all involved making a spring buttons, since these were buttons we dealt with on a daily basis. The only issue was printing a spring flexible enough to support the button without snapping or being too stiff. We had PLA and Flashforge printers to our disposal, but our resources could not easily handle the flexibility and subsequent resolution we needed. We ended up printing many different springs, and limited by the material and quality of our printer, as well as time, we decided to go an entirely different route.
We figured — all our button needed to be able to do was move down, and go back up.
- Manual Push Pin: Our first alternative idea was a “push pin” where the user would push the button pin down into a hole and would have to pull it back up in order to push it again. Therefore, the button would go back up by using manual labor, instead of a spring.
Nevertheless, we thought this idea was too simple. We still had over 24 hours left before the deadline, so we kept this idea as our last resort and went back to the drawing table. That’s when we thought about flexible plastic items, and one in particular was a ruler. We discussed how plastic rulers are still able to move up and down even though they are not thin pieces of plastic. When anchored at one side, with the other side of the ruler dangling, a ruler bounces up and down when the dangling side is pressed, similar to a diving board. Using that, we figured that by experimenting with different proportions, we could implement our “button.”
2. Diving Board: We though of many different ways to implement the diving-board like button as shown below. We played with many different proportions of thickness and sizes, as our “button” either kept breaking off at the base, or rarely budged. We also thought of ways we could reduce the amount of force needed to press the button by extending the end of the button, as shown below.
Yet, we realized we could reduce our button even further. Our button didn’t need to protrude outward like a diving board — it could be like a “ruler” cut out of our base.
3. Press Button: We then decided to make the shape a circle to make it more button-like, and we realized that we had seen buttons like this before in real life products.
In the end, we also decided to add a handle to our button since it was a bonus to make a “latched” button — one that stayed down when pressed down. Therefore, we made it so that the handle was the right length in order to make it somewhat “stiff ”when pressed down. The handle would then be used to raise it back up.
Designing the wearable
Our next step was designing the wearable. The first thing that came to our mind was a watch, with circles to fit the wrist. We decided to make a rectangular shape to hold the different compartments that we needed, which was a battery, a LED, and a resistor. We also needed a place to implement our button — we decided to incorporate our button into a lid. We designed a slide-in lid in order to make the battery easily replaceable, but also out of sight.
We decided to use press fits to fit the button, so we measured our items and in created a divider that would separate the battery and LED. We also thought this would be nice as the divider would serve as the elevated platform that the button would touch. We decided to use an elevated platform in order to reduce the amount of force needed to push the button down. For the divider, we also decided to leave space on one side in order to have a place to put the resistor.
Since our primary objective was to make an LED light up, we also thought it would be nice to have the LED be poking out of the wearable. Since our lid was detachable, we decided to make it poke out of the side instead of from the top. Lastly, we added ridges in order to implement our sliding mechanism for our lid.
After sketching our compartments, we then created our 3D model.
Connecting our circuit
Lastly, we needed to connect our circuit. We first wanted to put tape on the sides of the wearable, in order to have a clean look, but our copper tape did not conduct electricity well. We discovered that not all tape is created equal, as some parts of the tape worked, while others didn’t. We rethought our tape design and came up with this:
We wanted to reduce the amount of tape we needed to rely on by using the tape to stick the ends of the resistor to the short end of the LED and the positive side of the battery, as shown above.
Yet, even implementing this design was long. After grabbing our tweezers and placing the tape on carefully, making sure every part of the tape was touching other parts, our circuit still wasn’t working. We knew this wasn’t our button as even putting tape to complete the circuit didn’t work. Something deceptively simple turned into hours of mindless re-taping.
With just a few hours left, and no voltmeter or soldering available to us, we grabbed our tweezers and dissected the board methodically. With our hands we connected the metals together and placed the other ends at different parts of the circuit to determine when connection was being lost. After hours of fiddling and trying out different pieces of tape and different orientations, we managed to pull it all together.
Our advice — get better tape, or just use metal. Also, always have a voltmeter on hand to do continuity tests.
End Result
This was the end result of our wearable!
