Have you ever heard of charging your phone just by walking?
Yes!! is is possible by an short experiment. Here's a little secret on making insoles that can charge USB devices...!!!
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Step 1: Concept Behind the Project
The secret behind this experiment is "Piezoelectric Disk". The piezoelectric disk generate a voltage when deformed (change in shape exaggerated)
Step 2: Parts/Materials
- Piezoelectric Disk(6*)
- 1N4007 Rectifier Diodes(4*)
- Wires Aluminium
- Old Pare Of Shoes
- Contact Adhesive
- 3.7v mobile battery
- USB Port
- Voltage Regulator 5v
- USB DC-DC Mini PFM control (0.9-5v) (step up convertor)
- Lithium Battery Charger Board USB 1A 18650
- Electric Tape
Step 3: Measuring&Cutting PVC Board
Trace your shape of sole on your PVC material and cut it carefully.That cut PVC sheet will act as a base plate where you had earlier made your circuit.
NOTE-choose your base material carefully. i have tried every thing wood, rubber, hardboard etc but according to me plastic is best, but also choose your PVC material very carefully it should not be too thick nor too thin, it should be 2-3mm
Step 4: Measuring and Cutting Board
Make a triangle in between the base plate such that three piezoelectric disc can be fitted inside,then Make three holes on your base plate in your triangle , of size of inner circle of piezoelectric disc.
Why i made these holes?
This holes will help you bend your discs properly, while walking can create enough power to charge your phone.
Step 5: Pasting Piezoelectric Disc
Pasting your piezoelectric on your base plate on the cut circular holes,and do same thing on other side of your base plate and then made your "sandwich"
Why i have called This whole arrangement "sandwich"?
It is best suitable word i can think for this arrangement. piezoelectric disc will act as a bread and base PVC cutted material act as a binding agent.
Step 6: Connecting All Disk Together
Solder all disc in parallel to each other .don't connect these in series because we need more current then voltage.And repeat the same thing in other side and connect both positive and negative wires together, so in end we will get only two wires (+)&(-) containing whole current
But here we have a problem....
By our whole arrangement we will get AC(Alternating current) but to charge ant USB devise we need DC(Direct current). So we will attach a Diode bridge to convert AC to DC.
Step 7: Connecting Diaode Bridge
Diode bridge or full wave rectifier device to convert AC to DC current without changing the amount of current.So solder both wire to diagonal corners of bridge and by other two corner will get our DC current
NOTE- solder wires and make your bridge carefully because we have to be careful about 'forward Biassing'and 'reverse biasing'
Step 8: Adding Foam Pusher
We have to add form pusher on our discs, because of our comfort and main reason- because of surface area "Lesser the surface area More the Pressure"
Step 9: Testing on Voltmeter
Now we have to test our whole arrangement On voltmeter
It should produce
- 10-15v pressing by hand
- 20-25v while walking and
- 25-30v while running
Pin No Function Name
1 Ground (0V) Ground
2 Ground Input voltage (5V-18V) Input
3 Regulated output; 5V (4.8V-5.2V) Output
The two wires from diode bridge containing DC voltage ,will now be connected to voltage regulator
The first wire should be connected to input pin where as , the another would be connected to ground pin
Step 11: Making of Power Bank
For making a power bank , firstly connect the positive output point of lithium charger to the positive terminal of battery and further connect that wire to the input (positive) point of step up convertor(5v)
And now vice versa with the negative point.
Note- As you can see i have used mobile battery instead of cylindrical battery (both are same thing of 3.7v)
and I have used double sided board in place of to boards (it is better, it occupies lesser space)
Step 12: Connecting Power Bank to D.C Generator
The output and ground points of D.C generator would be now connected to the input points of lithium charger.
And taped it well....
Step 13: Final Setup
Connect the positive points of U.S.B port to the (+) output end of step up convertor and negative end of U.S.B port
would be firstly connected to switch,then further connect the same with the output (-) point of step up convertor......
If you have any queries then send me mail on "email@example.com" write it in comments
Participated in the
Green Electronics Contest 2016
Participated in the
Trash to Treasure Contest 2017