Electronics and PCB Design

For our final yoyo design, we wanted our design to light up our Citgo sign when the pyramid of the Citgo sign on our design is pressed. To do so, we brainstormed a lot of ways on how we can integrate the electronics in our design. Ultimately, we decided designing a PCB would be the easiest to ultimately integrate within our design and manufacture. 

Designing the Circuit: 

When designing the PCB, our biggest constraint was the size of our batteries. We decided to use 10mm coin cell batteries, because of their size. The CR1025 are 10mm coin cell batteries with the highest voltage we could find at 3V. Since we decided, we would want at least 2 LEDs to light up our yo-yo, and the sum of the forward voltages of these LEDs would exceed 3V when put in series, we opted for using 2 coin cell batteries. Here is our final circuit, with 2 batteries, a current limiting resistor, 2 LEDs, and a push button switch all in series. Below that are calculations of finding the current limiting resistor using Ohms Law. Edit: the calculation below is incorrect because the conversion of 20 mA to Amps should be 0.02 A not 0.2 A, which would result in a current limiting resistor value of 10 Ohms. 

Electronics BOM:

Here is our preliminary BOM for our first prototype! Finding a push button switch that could fit in our design was a little hard but eventually we were set on this one because of its size and functionality:

Push Button Datasheet: https://www.digikey.com/en/products/detail/panasonic-electronic-components/ESB-33535A/3873298