Lauren S.

Hi, engineering has always been a passion of mine, and I love to show it at BlueStamp! My starter project this summer is the Mini POV4 and my main project is Battery Charging Shoes.


Castilleja School


Rising Sophomore


Through the six weeks I spent at BlueStamp, I delved into electrical engineering and physics. I didn’t finish my main project, but I gained a lot of skills that I will use in the future. I now know much more about piezoelectric and inductive charging than before, and how ineffective they are for charging a battery. Also, through this experience, I got a taste of the average engineers design process. Inventors and innovators try many methods of completing a task before finding a solution, and this is what I experienced first hand at BlueStamp.

Main Project

Inductive Charging

The second iteration of my battery powering shoes uses inductive charging and Faraday’s law of induction to charge my battery. The component that I show in the video is completely designed by myself. I used the 3d printer to print the tube of the inductor. Then, I coiled the magnetic wire several times around the tube and placed the magnets inside. Coiling the magnetic wire was very difficult, since I didn’t have a specialized machine e to coil it around the tube. I used a drill to secure the coil around the tube. I attempted coiling it by hand, but it was taking far too long.

When the magnets move throughout the wire, the change in flux creates voltage. In succession, several capacitors would have to be used to smooth the charge, because the voltage is constantly varying. The highest voltage spike, produced by the component, was about seven volts, it was still not charge to charge a battery efficiently.

Through this second attempt at charging a battery through walking, I learned a lot about the daily inventor’s struggle. I will never except the “impossible”, but with the time I have at BlueStamp, it its just not ethical to continue, but I would love to look farther into this subject later.


  • Magnetic Coil
  • Earth Magnets (6)
  • 3D printed tube
  • Adhesive (to keep the parts together)

Full Circuit without Coil
Magnetic Coil Component
Magnetic Coil Component

Piezoelectric Element Charging

This Milestone taught me a lot about drawing and testing circuits. Through this project, I used new tools: a multimeter to test the voltage of the circuit, an oscilloscope to observe the voltage over time for the piezo, a power supply to adjust the buck converter, and a bread board to test my circuit.

Charging a battery with the piezoelectric element was the hardest part of this project, because the piezoelectric elements could not produce enough current to charge a battery. However, the piezos produce a very high voltage, so in order to prevent overpowering the battery, a buck converter would have to be used to step down the voltage. Through the piezoelectric approach to creating battery charging shoes, I learned that the use of piezoelectric elements is not ideal for charging a battery. Although, it was sufficient in lighting a LED. Still, when I charged a battery with an increased number of piezoelectric elements, the results didn’t change. Because I could not use the piezoelectric elements to charge my battery on the shoe, I used a different transducer. The method I am using now to charge the battery is inductive charging.


  • Piezoelectric Elements
  • Full Bridge Rectifier
  • Oscilloscope

Starter Project

My starter project is a DIY Colorful Light Painting & POV(persistence of vision) Toy. When this device is moved horizontally back and forth, pictures and letters can be seen in the air!

To begin my project, I soldered all of the components to my circuit board. In the process of soldering, I accidentally soldered one of the LEDs, which are polarized, incorrectly. To correct this, I had to desolder the entire LED out of the circuit. This was probably the most difficult part of making the mini POV. Once I had desoldered the LED, I re-soldered it correctly. While I was struggling with re-soldering the LED, I considered soldering in another LED, because it was less destroyed. However, I could not use the other LED, because it didn’t have a ground pin. Eventually, I was able to solder back in the original LED. My advice for anyone that is going to make this starter project is to pay attention to the polarization of the components on the circuit board, because this cost me a lot of time. Finally, I continued to solder the rest of my components, turned on the battery, and observed the light show!

POV Module

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