Week 9 - Preparing for the presentation

We met outside of class to make a video for the final presentation. We brainstormed our ideas of how long we wanted the video to be, and what would be the most simple, yet effective way of showing that out product works. One group member volunteered to wear the shoe and walk during the presentation, while another member would film the multi-meter and a third member would film the entire act. Before filming, the piezo crystals on the shoe sole were adjusted according the member's foot map to increase the mechanical energy input on them. The initial voltage reading was noted down and the person walked for 2 minutes and then the final voltage reading was read. An increase of 0.01 V was obtained, from 0.26 to 0.27 Volts. That was a success for the group. Because if the person keeps on applying the same pressure on the shoe for 4 hours, they will fully charge the battery, assuming it is an ideal system. The figure below shows the team members making some fianl adjustments before filming the video for presentation.

Figure 1: A team member placing the rechargeable battery in the case before testing and filming. 

Week 9 - Final touch

Figure1: Circuit board, the rechargeable battery and 4 piezo crystals in series attached to shoe sole

Figure2: Completed sole implemented in a shoe, with battery case attached at the back of the shoe

According to our project  timeline, we should be finishing up with everything and implementing the electrical part into an actual shoe by week 9, and we succeeded in doing it. The group members have been testing the piezo crystals with the circuit board by simply using their palms or fingers to apply pressure to the board, however, actual testing was needed. In lab this week, when we completed the shoe, one group member wore it and walked around the lab for about 1 min. A multi-meter was attached to the battery case at the back to monitor if the rechargeable battery was being charged. The initial and final voltages were compared and to make sure that the product was reliable, all 4 group members wore the shoe and walked for a minute. The increase in voltage readings were close to each other for the 4 trials, a mean of about 4 mV increase in a minute. Our prototype was ready to be shown in the presentation. We also concluded that our initial requirement of charging a 1.2 V battery in less than a day was met. Success ! 

Presentation Time!

Figure 1: Graph showing voltage over time

We had our presentation in Engineering on Tuesday! We didn't win the nomination for our team section, but we're still going to continue as hard as we can with our project. Our idea still is a very viable one and could help a lot of people if put in the right direction. Before the presentation, we did one last check to make sure we were storing energy, and we were! The Matlab plot showed that after it was charged up, it had a constant 5 volts that would allow it to charge a battery.

Week 7: Electrical Components complete

Completed Piezo circuit

The final product of our electrical design is complete. After numerous circuit diagrams and multiple bread board designs the most voltage efficient circuit was created. The final circuit board actually runs similar to a breadboard design, with a copper wire running through one entire end of the board. While creating the circuit, we made a mistake in attaching the first copper wire, as it turned out to be from some sort of resistor component. We also 3D printed another piezoaqueduct for our final mechanical design. Along with this, we learned to utilized an arduino to collect real-time voltage data to display data.

Piezo crystals hooked up to arduino

Week 6, 3D Print

Image 1: 3D printed piece

Image 2: Intended function; blue:force; orange:tool; green:piezocrystal

3D PRINT SUCCESS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
The purpose of this piece is to direct the input force onto the piezo crystals. Since the crystals actually produce voltage from distortion and shearing, a sharper directed force produces better electricity. The modeled aqueduct-like structure, dubbed the "piezoaquaduct", focuses the relatively spread out pressure onto specific points in the crystals. This simple mechanical feature should greatly increase the yield of the piezoelectric generator.

Week 6, Engineers make a Quantum Jump

a circuit diagram showing the various component
used to charge the battery

After several weeks of research and experimentation, we finally set up the right circuit diagram which was able to increase the voltage of a 1.5 volt rechargeable battery from about 0.03Volt to 0.04volt during our first test. this value showed a general increase with further testing. although this voltage increase is not that huge of a value, we used only one piezo to perform this experiment and also our circuit lacked a DC-DC converter which is basically to be used as a tool for ensuring that the charge in the capacitor is efficiently and effectively transferred to the rechargeable battery and hence reduce power loses or voltage leaks.

Week 5, The fails and wins

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A picture of Shaumik trying to 3D print the aqueduct-like structure

We decided to go to the innovation studio to perform some tasks on the project. the first thing we did was to use the soldering iron to solder all the defective piezo and then tested them all out to make sure they were working. we then connected the set of piezo on a board to test whether series and parallel connections produced the most voltage since our previous test did not give any strong confirmation for either. after testing which connection works best, we then set up a circuit consisting of a 470 micro farad capacitor which was connected in series with a diode to ensure there is unidirectional flow of voltage and hence current. other component were also attached to it and through a continuous application of pressure to the piezo disc, we were able to charge the capacitor to about 1.9volts which was very constant until the capacitor was discharged. we attempted to 3D print an aqueduct-like structure to focus the pressure on the piezo crystals. this was however not successful as the 3D printer was malfunctioning