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Piezoelectric Energy Harvester - Capstone Design

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1 Introduction
1.1 Problem Statement
Now a days the cost of the energy is increasing day by day, and the supplies of
the f...
Figure 2: counting numbers of cars that are passing abu-dhabi al ain road
Also for example in abu-dhabi university in 2013...
people will not be able to know that this technology is there. .this novel idea is
not only clean but it is also renewable...
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Piezoelectric Energy Harvester - Capstone Design

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•The complete design of a real size piezoelectric system, enabling to harvest from roads and generate, store, and supply electricity to light up street lights.
•Sizing and construction of a scaled down prototype of the real size piezoelectric energy harvesting system, Storage of electrical energy outputted from system, supplying power to the load and smart system, Power monitoring system to monitor energy stored, supplied, and outputted.
•Complete PCB Design and circuit board building in accordance with Arduino UNO Rev-3 on EagleCAD as well as LCD to display readings.
•Prototype commissioning and performance testing of entire system comprised of 3 main subsystems: Generation, Power Storage, and Power Monitoring System

•The complete design of a real size piezoelectric system, enabling to harvest from roads and generate, store, and supply electricity to light up street lights.
•Sizing and construction of a scaled down prototype of the real size piezoelectric energy harvesting system, Storage of electrical energy outputted from system, supplying power to the load and smart system, Power monitoring system to monitor energy stored, supplied, and outputted.
•Complete PCB Design and circuit board building in accordance with Arduino UNO Rev-3 on EagleCAD as well as LCD to display readings.
•Prototype commissioning and performance testing of entire system comprised of 3 main subsystems: Generation, Power Storage, and Power Monitoring System

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Piezoelectric Energy Harvester - Capstone Design

  1. 1. 1 Introduction 1.1 Problem Statement Now a days the cost of the energy is increasing day by day, and the supplies of the fossil fuels or the traditional sources start decreasing , beside the environ- mental problems and issues that start aggravated and creating many problems. Therefore sustainable forms of energy have become very important. The high priority was to find another sources of energy that are clean and efficient. So the renewable sources of energy like solar, wind, waterfalls and etc was the ideal and perfect solution to wean ourselves off of most of the problems. One of the renewable energy sources that can be used and converted into useful energy is the vibration or the kinetic energy that cased by the motion of the objects, like the motion of the vehicles on roads or the footsteps of peoples around us, this kinetic energy can be captured and converted into electrical energy by using piezoelectric technology. Figure 1: footsteps causing a vibration [?] In small experiment we counts the cars that are passing al ain- abu dhabi road coming from al ain in 10 minutes at 7:30 on 1st-may-2014 am more than 650 cars passed the road, which has 4 ways. All these cars can create a huge useless vibration energy in 10 minutes so can we imagine how much vibration energy can be created in one day. 1
  2. 2. Figure 2: counting numbers of cars that are passing abu-dhabi al ain road Also for example in abu-dhabi university in 2013 the number o under grad- uated students was 4965 students [?]. If we just consider 25Our objective and goal in our project is to convert parasitic energy loss into a beneficial gain in other words convert the vibration energy into electrical energy and have an ef- ficient, clean and sustainable parasitic energy harvesting system. The parasitic energy or the vibration energy on congested roads is harvested using piezoelec- tric devices which use the mechanical strain that is generated by the vehicles and convert, it into electrical energy. This energy is used to run many systems like street lights, speed detectors, radars, house lights, or for example entering or attending card checking system and also it can be fed back to the grid. 1.2 Motivation in fact converting this useless kinetic energy into useful form of energy is a greatest solution, for many energy problems, as we know the main problem with renewable energy is that it is inconsistent due to the instability of the sources like the wind, sunlight, or lack of water pressure. For example harvesting energy from the sun or the solar rays is only possible during the day time, or if there is clouds that will make harvesting the solar energy very difficult. But this problem does not apply in piezoelectric energy harvesting system. This energy is solely driven on the mechanical strain created by the vehicles and the piezoelectric system is constantly generating and storing this energy during the day and night regardless of low or high traffic. Also this technology is environmentally friendly, it is not noisy like the wind mail it is also don’t causes any increase in the carbon footprint, moreover it is don’t need a large places to be exist and it is not affect the natural views because it can be constructed under the construction, such as streets 3. It is also safety and no risks associated with this technology so it will not affect safety in the buildings and constructions. The installation of the piezo ceramics will be under the streets or floors so cars or 2
  3. 3. people will not be able to know that this technology is there. .this novel idea is not only clean but it is also renewable. Figure 3: piezoelectric ceramics can be constructed under the construction [?] The maintenance cost is very small and minimal due to the long life cycle of the piezo ceramic ,although the initial cost can be high but it may reduced just as solar power which has spread all over the world and the high initial costs which was very high at the beginning have started reducing. this technology has the ability to produce up to 44 mw of electricity every year from one-single lane, which is stretched through 1 km or roadway which can supply electricity up to 30,800 homes. 30,800 households can have clean and free energy for a duration of one year that cuts down a lot of bills, maintenance cost of a plant, carbon footprint, fossil fuels or other resources [?] . Such idea can fit well in an airport, train stations, malls, streets or any crowded places. Like schools or hospitals. It can light up streets, households, automatic doors, or anything that can have thermal or mechanical strain. 2 Literature Review This technology, once successful, would be able to provide power for the street lights. Moreover, this power costs less, it is clean and highly efficient (20-70% efficiency) [?]It is applied in places like: Tokyo Railway Station in Japan where , where the floors where a piezoelectric sheet is placed people pass by electrical energy is harvested from the mechanical stress applied on the sheets by the footsteps of passersby.This also this powers the ticket gates. [?].When crystals gain a charge under mechanical pressure, distortion, or stress, it is said to be piezoelectric. A few of the materials that exhibit this form of energy are: Quartz 3
  4. 4. crystals, Barium titanate, lead zirconate, and lead titanate. Excluding quartz, all of these materials are ceramic. When these materials are under mechani- cal stress, the lattice structure gets deformed and this causes piezoelectricity. The piezoelectric devices generate electricity due to the special sheet which is composed of two thin metal sheets enclosing a thin layer of quartz crystals or any other crystal exhibiting piezoelectric characteristics. Under pressure, these crystals deform and cause piezoelectricity. The Energy harvester circuit will harvest this energy and convert it to electrical energy. The mechanical energy is transformed into electrical energy using transducers. [?] Figure 4: Lattice structure of Lead Zirconate Titanate (PZT) and Barium Ti- tanate after mechanical stress Lead Zirconate Titanate (PZT) is a widely used ceramic material for piezo technology. This material is made up of elements, namely lead, zirconium com- bined with titanate. This material is made under very high temperatures. It can operate under high temperatures and it also has greater sensitivity than most of the other piezo ceramics. This material has a perovskite crystal structure and each of its unit consists of a small tetravalent metal ion and a large divalent; the small tetravalent ion in the lattice is either titanium or zirconium and the large one is lead. Each of these crystals has a dipole moment depending on its symmetry: Either tetragonal or rhombohedral. [?] When mechanical stress is applied the molecular dipole moments are altered or reconfiguration occurs. Piezoelectricity will then accumulate due to three factors: Orientation of po- larization or dipole density P within crystal, crystal symmetry, and mechanical stress applied. [?] The crystalline materials have to operate at 50% of the Curie Temperature. Piezoelectric materials can be affected strongly by temperature due to the fact that magnetic materials have a limited value for temperature known as the Curie temperature. Curie temperature is the temperature at which mag- netic materials change sharply in their magnetic properties. [?] The piezoelectric material has the following to abide by in terms of temperature: Temperature dependence of the coefficients are shown below: ˆ Materials: PIC151, PIC255, PIC155 graphs on the left ˆ Materials: PIC181, PIC241, PIC300 graphs on the right Temperature curve of piezoelectric charge coefficient 4
  5. 5. [?] Figure 5: Stress Strain Graph for PZT In Figure 5 Curve 1 is with the nominal operating voltage on the electrodes, Curve 2 is with the electrodes shorted (showing ceramics after depolarization) The PZT material can withstand pressure up to 250MPa without breaking and this value should not be approached under normal conditions because depolar- ization occurs at 20-30% of the mechanical limit. [?] This energy harvesting circuit will help in converting the piezoelectric energy 5
  6. 6. Figure 6: Energy Harvesting Circuit [?] into electrical energy in order to be stored in a battery to power up the street lights or traffic lights. This chip is used particularly for the piezoelectric sheet. The minimal possible circuit is used, as anything complex will consume or cause loss of energy which in this case we need to store.The Energy harvester Circuit as well as the Charge control circuit is shown below: Figure 7: Charge Controller Circuit [?] The charge controller circuit will rectify the AC current as we might either need AC or DC according to the needs of the devices. Later on, it will also include a charge monitoring system in order to detect whether the battery is full or not and, accordingly, proceed to charge up the battery or stop. The first application of a piezoelectric material was that created by Dr. Ville Kaajakari who put a tiny piezoelectric generator in order to convert the energy generated from walking in order to power mobile phones, GPS, mp3 players etc. [?] 6
  7. 7. Figure 8: Piezoelectric generator in shoe [?] This next application is that of an everyday common device: the gas lighter. Here the application of piezoelectric is used in order to generate a spark which ignites the gases by generating a current. So, two piezoelectric materials are put in such a way that their polarization is reversed. As more stress is applied more polarization occurs. In order to light the lighter the two materials are faced towards each other on the same charged side to light it up. They are connected in a circuit with a spark gap for the lighter to ignite the spark, there- by pressing the two piezoelectric materials together. This creates a charge that travels through the circuit to the device. The charges neutralize a spark which goes through the gap which in turn will burn the gas to create fire. [?] Figure 9: Lighter application of piezoelectric [?] Another application is when piezoelectric energy is harvested from human movement. To be precise this is applied in Tokyo, Japan by the East Japan Railway Company. The flooring is embedded with piezoelectric materials at the ticket gates. This is powered by the stepping pressure on the sheets at the gate to power up the lights in the station or the automatic ticket gates. [?] There are many different types of renewable energy such as solar, wind, geothermal, bio fuels, hydroelectric and more. The problem with most of these renewable energy sources is that they are natural resources and most of them need to be used or consumed in order to produce energy. Some are taken back into the environment but, if contaminated, are hazardous to the environment. 7
  8. 8. The other problem is all these renewable energy sources need a staffed plant to function and produce electricity. It comes with expensive machinery: turbines, generators, propellers, protection devices, etc. Most need maintenance for both the plant and the machinery. The plant uses electricity, too, so the cost is high and is constant throughout production. Whereas parasitic energy is a form of energy that is taken from wasted energy or from loss of energy and converted to electricity. The initial cost is the only cost incurred besides some maintenance cost. Other than that, it poses no threat to the environment. The other benefits are zero carbon footprint emission, no harmful materials used in production, no plant required, no staffing. 2.1 Applications Piezo technology can be found in all areas of the market such as medical field ,mechanical or automotive engineering, and semiconductor technologies. This technology exists in our daily lives such as generator of ultrasonic vibrations which are applications in cleaning bath for glass and jewelry and also in medi- cal tooth cleaning. Piezo technology is used in metrology where the ultrasonic sensors give off a high-frequency sound pulses which surpasses the human hear- ing capacity and then it receives signals from the objects that reflect the pulses. Here piezo force sensors are used. In ultrasonic technology the piezoceramics are used to generate ultrasonic waves in frequency which ranges from 20 to 800 kHz. This can be used for diagnosis an therapeutic application such as tartar removal or lithotripsy. Its used for scientific instrumentation pumping and dos- ing, medical technology, and harvesting energy [?] Piezoceramic devices fit into four categories: piezo generators,sensors,piezo actuators, and transducers. 2.1.1 Piezoelectric Generators Piezoelectric ceramics will give output voltages which is sufficient to spark across an electrode gap and this is used as ignitors in the following: fuel lighters, gas stoves, welding instrumentation’s, and other devices. Piezoelectric systems are simple and small and they are advantageous over other systems which include permanent magnets, transformers and capacitors. Piezoelectric energy can be stored as they resemble solid state batteries for electronic circuits. 2.1.2 Sensors A piezoelectric sensors which transform a physical parameter like acceleration or pressure into an electrical signal. Some sensors are acted upon for gener- ating vibrations to convert to electrical energy and some apparatuses have an acoustical signal which will create the vibration and these are in turn converted. Piezoelectric system can have a visual, audible, or physical output to the input given from the piezo sensors. 8
  9. 9. 2.1.3 Piezo actuators: Multilayer, Stack, Bending, Stripe The piezo actuator will take the electrical signal into a exact but controlled physical displacement in order to regulate exactitude machining tools, lenses, or mirrors. These actuators are also used for control of hydraulic valves, act like small-volume pumps or special purpose motors or others. Piezoelectric devices have an advantage and that is that they are unaffected by energy efficiency losses which will not let them use the miniaturization of electromagnetic motors which limits them to sizes less than 1cm3 . These devices also lack electromagnetic noise. There are different types of piezo actuators: Stack actuators which is made in on of two ways such as discrete stacking or co-firing, this all depends on the user’s requirements. Another type is stripe actuator or the bending actuator which has thin layers of the piezoelectric ceramics which are bonded together. 2.1.4 Transducers Piezoelectric transducers will transform electrical energy to vibrational mechan- ical energy which is usually sound or ultrasound in order to carry out a task. These devices will generate sounds that is heard and has several advantages either relative or as an alternative to electromagnetic devices- these devices are very compact,simple, and very reliable, with minimal energy that can output very high level of sound. This a matches criteria of the the needs of batter- powered devices. Piezoelectric effect is know as reversible so a transducer can both generate an ultrasound signal from the electrical energy and change incom- ing sound to electrical energy. In certain devices for measurements of different units a single transducer is use for signaling and receiving in other cases two transducers are use for separate roles. These transducers are also used in order to generate ultrasonic vibrations for cleaning,atomizing liquids, drilling, milling ceramics, or other materials, welding plastics, medical instrumentation, or other reasons. [?] A piezoelectric circuit is used worldwide for a variety of reasons. The circuit used to test the bulbs is modified in a way that can use any suitable high voltage source as the substitute for piezoelectric crystal. This circuit can be put in shoe insoles,fishing lure, toys, or other applications that needs a light source. In other applications by placing capacitors that are parallel with the crystal and the light source, the capacitor is charged by applying pressure to the crystal. This can be useful by placement of piezo discs on the pedal of a bicycle to light up the flashlight in rural areas where electricity is scarce. 9
  10. 10. Figure 10: Applications of Piezoelectric ceramics [?] In figure 1 the piezoelectric circuit is used for a light tester that will makeup a first embodiment of the present invention, figure 1A shows that the light tester is using an alternative high voltage source and figure 2 shows the schematic of the circuit which has been altered in order to include the light sources. 10
  11. 11. Figure 11: Applications of Piezoelectric ceramics [?] Figure 3 shows the fishing lure that uses a piezoelectric circuit. Figure 4 and 5 shows how toys use piezoelectric circuit and in a industrial scale. 11
  12. 12. Figure 12: Applications of Piezoelectric ceramics [?] Figure 6 shows how a shoe using a piezoelectric circuit can light up an LED. Figure 7 shows the schematic for another use of the present invention that includes a storage capacitor. Fire 8 shows how a crank mechanism is used for the circuit to operate in figure 7. 12
  13. 13. Figure 13: Applications of Piezoelectric ceramics [?] Figure 9 uses a camera which combines the circuit of figure 7 in order to operate the flash. Figure 10 shows the piezoelectric circuit in a bike pedal. Figure 11 shows and emergency light signal that uses a piezoelectric circuit. [?] 13
  14. 14. 2.2 Report Outline The remaining chapters in this report are the following: design, implementation, project management, results and discussions, summary of entire report. 3 design The main design for us was implementing a prototype for a street with piezo materials installed in the design to harvest the energy from the motions of car model, but during our researches we found that building a prototype is very difficult, first of all the piezo materials was very expensive, where each piece of 2 in2 is worth more than 400 dhs more over the current that coming out from the piezo was very small (the maximum output power was less than 2.5mw) and we need more than one piece to generate enough power for our system . So we make up our mind to build a simple design that can generate a power from piezo materials, then we have to store it , measure it and then supply it to the load which will be a small led. The design contains three main systems electrical system, mechanical system and programming system. 3.1 electrical system Electrical system this system is divided into three stages14: 1. generating electrical power 2. storing the electrical power 3. supplying the electrical power to the load and the smart system. Figure 14: the three stages for the electrical system 3.1.1 generating the electrical power In this stage we have to extract the power from the piezo materials. The energy generation stage has a mechanical structure that is built in order to generate enough power for the system to function and produce electricity to power the other subsystems. The mechanical structure have an array of piezoelectric discs that are connected to produce maximum amount of voltage and current. The mechanical structure is designed in a way to apply enough pressure without breaking or damaging the piezo discs. The structure has two layers: one lower layer with the piezo disc, a second layer has a bolts that transfer the pressure 14
  15. 15. that applied on the upper layer onto the discs. The next pictures showing the generating stage . For our design we used 12 piezo buzzers as shown in the next picture 15. Figure 15: piezo material buzzer These components can supply us with a voltage between zero and thirty or more depending on the pressure that we apply in other words, when we apply a stress on the piezoelectric material, an electrical field is induced this what we called the piezoelectric effect . Those buzzers have two poles , positive and negative( the covered part or the white color is the anode, the metal part is the cathode) when we feed them with electrical voltage they start vibrating we used them in our design because they were cheaper and available for us. 3.1.2 storing the electrical power In this stage we have to store the energy that is generated in storing unit, there is two methods to store the power, the first method is using piezo harvesting kit, boost converter ,charge controller and a battery. The second method is to build a normal circuit that convert ac current to dc current and store it in supper capacitor. 3.1.3 method 1 : In this method we need to use the following: 15
  16. 16. 3.1.4 piezo harvesting kit eh300/30116 .: This device converts the ac power output from a piezoelectric discs to a dc power output, it construct of 1. a full-wave rectifier bridge which convert the ac current that reverse it direction into one direction current and 2. charge management and dc-dc conversion ic that control the input power and produce a stable dc current 3. some storage capacitors for storing and smoothing the power. Figure 16: piezo harvesting kit eh300/301 [?] Figure 17: piezo harvesting kit eh300/301 main parts [?] 3.1.5 boost converter : This part is depend on the size of the battery that we are we going to charge, since the output from the harvesting kit are 1.8v, 2.5v, 3.3v, and 3.6v we may need to charge more than 3.6 v battery , in this case we need to boost the output voltage from the harvesting kit to the needed voltage using boost converter that can step up the dc voltage 16
  17. 17. Figure 18: boost converter [?] 3.1.6 method 2 : In this method we need to design a simple circuit that contain 1. bridge rectifier which convert the ac current that reverse it direction into one direction dc current. 2. smoothing capacitor to smooth the output of the rectifier 3. voltage regulator to generate a fixed output voltage 4. super capacitor to store the power. It was very difficult to chose the most suitable method for us, method 1 was good but very expensive, method 2 was cheep but we can’t guaranty the results. So method 2 was our first choice. How bridge rectifier work19 Figure 19: bridge rectifier work [?] A diodes bridge rectifier is construct of four diodes connected as shown in 19. Points a and c are the inputs, during positive cycle of the voltage diodes 17
  18. 18. d1 and d3 are forward biased so they conduct the current or the voltage but d2 and d4 are reverse biased so they operating like an open circuit. So current flows as shown in part1 . During negative half cycle, the diodes d2 and d4 are forward biased and the diodes d1 and d3 are reverse biased so the current will flow as shown in part 2 in both cases current flows through the resistor in the same direction, but increasing and decreasing so we get ripple current in the resistor or the output [?]. Calculations for the smoothing capacitors: The output from the rectifier on its own would be a cycles of half sine waves and the voltage varying between zero and 30v. So to smooth the output of the rectifier we use a capacitor which placed across the rectifier output , the rectifier will charge the capacitor then when the voltage from the rectifier drop down the capacitor will provides the voltage that it store it. Figure 20: the bridge current and smoothing capacitor current [?] The diagram 20 shows the output from the bridge and the capacitor smooth- ing voltage. The best capacitor should match the next condition R * c ¿ 1 / f R = the resistance of the load c = value of capacitor in f f = the frequency - this will be two times the frequency of a bridge [?] . If we are going to use about 500 and the maximum frequency is 4 hz then the required capacitor is more than 125f Picture21 is showing the method2 simulation: In this picture 21 we chose a power source as piezo because there is no piezo elements in the multism program the storing unit will be a super capacitor In this picture 22 we can see the simulated output voltage from the bridge diodes and how it is ripple, to construct the bridge diode we will use a schottky diodes those diodes are perfect for our project since they are consuming very less power. See ****** In this picture 23 we can see the simulated output voltage from the smooth- ing capacitor and the regulator, the yellow line is the smoothing capacitor out- put, the blue line is the regulator output 3.1.7 supplying the electrical power to the load and the smart sys- tem Our load should be very simple because the output power from our system is very small we chose to use leds and rheostat as a load connected in series with 18
  19. 19. Figure 21: multism simulation for storing energy stage Figure 22: the output voltage simulation from the diodes bridge 19
  20. 20. Figure 23: the output voltage from the smoothing capacitor and the regulator 20
  21. 21. a switch, the aim of the switch is to control the supply of the energy . We can adjust the rheostat to change the brightness of the leds24. Figure 24: supplying the electrical power to the load stage In this picture24we can see the simulated circuit for the load where the led is connected in series with the rheostat and the switch. 3.1.8 Arduino Part In this part of the report the description of the problem that we face and the objectives we are trying to achieve will be explained. FSM models, flow charts, architecture figures are put in order to describe to the reader exactly what we are trying to solve. Description of the whole design is explained in details here about every component used and every connection made between each component and system and the flow through the systems. The tools that are used for the components are used in FSM models and through flow charts and Multisim and/or Eagle PCB circuit connections. Description of the mechanical system is described in detail and how it con- nects to the other subsystems which is the electrical and the arduino system. Here the design of the mechanical system along with every components descrip- tion and circuit connections withing is described. The description is in the 21
  22. 22. Figure 25: the final design for the circuit form of pictures, circuits, and useful information. The electrical circuits and connections are drawn on multisim and EAGLE for PCB printing and circuit connections to be clear and concise. The arudino connections with the system and the LCD are in the form of circuit and the additional code is written and explained in details. 3.1.9 Implementation In this section the implementation of our system is described. Every components purposed using connections or code is described..The circuits, codes, and figures from software are explained and shown as well as the progress from the progress presentation model to the current and final model is shown along with the description of all the problems faced and the changes made to the model. List of components, circuits, models, circuits, and softwares used and changed are all corrected and explained in details. 3.1.10 Project Management In this part of the report the members explain about their background as well as the progress that has occurred is shown on the Gantt chart and compared to the one made in the proposal presentation. The software elements and the planning involved is described as well as the communications between team members and the professors is shown as proof via emails.Weekly report, minutes of meetings, supervisor meetings are all arranged and put in the report. 3.1.11 Results and Discussions This part of the report will show all the evidence we have gathered throughout the whole period of time that our system works and is fully functional. The tests that needed to be carried out are shown as evidence along with the results. Any changes made is discussed and explained in details. 22
  23. 23. 3.1.12 Conclusion and Future Work Concluding with the summary of the entire report and what we have learned from the design building process technically and about working as a team. What we found out about the system about the materials over the whole time. Sug- gestions of how the system can be improved and what to expect in the future. 23
  24. 24. 4 Design The circuit that will be connected at the end of the piezoelectric and electric systems will be the power monitoring system previously the control system. The circuit which is after the energy harvesting system and storage will be monitored using the Arduino Uno Rev-3 and display on the liquid Crystal Display. The circuit and connections are drawn on Eagle CAD and the schematic diagram as well as the Board is shown below: 4.0.13 PCB Figure 26: Schematic diagram for the power monitoring system 24
  25. 25. Connections between components and details: ˆ Materials needed: Liquid Crystal Display 16x2 Arduino Uno Rev-3 10k potentiometer 1 MΩ, 100K Ω, and 330 Ω resi resistors(Voltage divider) Breadboard Pin headers ACS 712 Current Sensor LED ˆ Arduino connections to LCD: The pin headers are first soldered onto the 16 pins of the 16x2 Liquid Crystal Display. The connections between the two components are revised and the connections are made. The connections between the two are as follows: Pin 1(GND) of the LCd is grounded by connecting to the ground of the arduino at Gnd Pin. Pin 2(Vcc) of LCD is connected to the 5V pin on the Arduino. The LCd is now powered up and grounded for displaying output from the Arduino. Pin 12 and Pin 11 are connected to pin 4(RS) and Pin 6(Enable) pins respectively. Register Select(RS) pin will control the location of the LCD’s memory that data is being written to and this connects to Pin 12 (MISO) and this is the SPI communication medium for the LCD to display/write data onto the display that the Arduino outputs through pin 12(MISO). Pin 11 is also for SPI communication(MOSI)to device which connects to the Enable pin for writing to the registers. The data being displayed comes from here where the Arduino through pin 11 enables the registers for writing on the LCD and the LCD outputs the location of the registers that data will be written to. Next is the connection from the LCD D4 pin to digital pin 5: D4 pin is a data pin and there are 8 data pin D0-D7, these pins depending on their states being high or low the bits are being written to a register when writing or the values being read when you read from it and it is connected to digital pin5 which is with output of analogWrite() function hence the arduino will send analogWrite() function and D4 pin writes to the registers the depending on the state. LCD D5 pin to digital pin 4 which can have these functions digitalWrite() digitalRead()and so data is either being read or written. LCD D6 pin to digital pin 3 holds the same as D4 and the same in this case LCD D7 pin to digital pin 2. [?,?] 25
  26. 26. ˆ Arduino connections to Voltage Divider: Arduino Uno-R3 is connected to a voltage divider so as to measure the Voltage to output onto the LCD. The voltage divider takes the input which is going to be very high for the Arduino to takes since it takes a maximum voltage of 5V and 3.3V. So the Current that we have has a maximum of 50V and through the voltage divider of 1MΩ and 100kΩ and this will bring down the voltage for input to the arduino to 5V. The middle of the voltage divider is connected to the analog A2 pin on the arduino as this will take the analog value and using the code it will display the how much voltage is running in the circuit. The circuit is connected to R1 which is 1MΩ resistor and 100kΩ resistor is grounded. The A2 pin is carrying out functions of analogRead() so it reads the voltages that is being inputted to the Arduino to be read. [?] ˆ LCD connections to potentiometer: The potentiometer is used in order to adjust the brightness and contrast of the LCD and the connections are as such : The outer legs one of them is grounded and one of them is connected to 5V. The middle pin is connected to the Vo Pin 3 of the LCD which is responsible for the display contrast. [?] ˆ Current sensor connections to LED: The current sensor is used in order to detect the current that flows through the circuit and the LCD displays the voltage, current, power, and watt- hour on the display. In order to do this the current sensor’s GND is connected to the ground on the arduino and the 5V is connected to the 5V of the Arduino, the middle pin is connected to the analog A3 pin this pin is for the current readings to be sampled and is inputted to the arduino which using the function analogRead() and is processed in the Arduino and and sent to the LCD. [?] 26
  27. 27. Figure 27: Schematic diagram on board for the power monitoring system In this circuit diagram: The components used are Arduino Uno, 16x2 LCD character display, 10k potentiometer, resistors, LED, and ACS712 current sen- sor. The following has it’s own purpose in the design and it’s use is explained in the following few pages: Arduino Uno: The Arduino Uno is a board which has a microcontroller base on the AT- mega328. This board has 14 digital input/output pins,6 analog input, 16 Hz ceramic resonator, a USB connection, a power jack, an ICSP header and a reset button. Ithas everything necessary for the microcontroller to function by just connecting it to the computer via USB cable or by power it up using AC-to-DC adapter or a battery. Previous boards use FTDI USB-to-serial driver and the current model does not;on the other hand, it uses an ATmega16U2 which is programmed as the USB-to-serial converter. Some of the key features of the 27
  28. 28. Figure 28: Arduino Uno Rev3 Arduino are listed below: [?] ˆ Microcontroller - ATmega 328 ˆ Operating Voltage - 5V ˆ Input Voltage(recommended) 7-12V ˆ Input Voltage(limits) - 6-20V ˆ Digital I/O pins - 14 ˆ Analog Input Pins - 6 ˆ DC Current per I/O Pin - 40 mA ˆ DC Current for 3.3V Pin - 50 mA ˆ Flash Memory 32 KB (ATmega328) of which 0.5 KB used by bootloader ˆ SRAM 2 KB (ATmega328) ˆ EEPROM 1 KB (ATmega328) ˆ Clock Speed 16 MHz [?] 16x2 LCD character display A liquid Crystal display screen is an electronic device via which many devices can have different applications. A 16x2 LCD display is the most commonly used LCd in electronic devices. This LCD is 16x2 which means it has 16 characters with 2 lines. and each characters resolution is 5x7 pixels. Command and Data registers are present in this LCD. The command register will store the commands 28
  29. 29. which are given to the LCD and this is done by things like : initializing screen, clearing screen, setting cursor position etc. The data into the LCD is the ASCII value of the character. The pin diagram is shown below for an LCD [?] Figure 29: LCD pin diagram 29
  30. 30. Figure 30: LCD pin diagram connections 10k potentiometer Figure 31: 10kΩ Potentiometer The Rotary potentiometer standing at 10kΩ is and adjustable potentiometer and the pot is turned in order for the resistances to changes. The VCC connec- tions are connected to the outer pin whilst the ground is connected to the other one and the center pin is connected to have a voltage from 0 to VCC which de- pends upon the rotation of the pot. This can be connected to a mcrocontroller on an ADC to get varying inputs from the user. Int this case the potentiometer was connected between pin Vo of the LCD and ground and 5V ont he Arduino for changes in the contrast of the LCD. [?] 30
  31. 31. Resistors Figure 32: LCD pin diagram connections Resistors are electronic coponents which usually have a certain, non-alternating electrical resistance. The resistor’s resistance blocks the flow of the electrons that go through a circuit. These components are passive which is that it will only consume power and will never generate power. These components are added to circuits where it will work alongside the active components such as LEDs, microcontrollers, or other integrated circuits. Resistors limit the current, are used as voltage dividers and pull-up I/O lines. [?] LED: Figure 33: LCD pin diagram connections LED also knows as Light emitting diode is a special diode that will give off light when the electric voltage is give to it. It is a common electronic equipment that is used in a lot of devices. An LED has two heads that is used on order to give input voltage the longer head is the positive head called Post and the smaller one is negative head called Anvil. [?] 31
  32. 32. ACCS 712 current sensor: Figure 34: ACS712 -Current Sensor The ACS712 provides economical and the exact solutions that are needed for AC or Dc current sensing devices in industrial , and communications system. Sine we are establishing a power monitoring system we need to measure the current from the output of the system in order to calculate the power that the system generates and in order to do that a current sensing break out board is needed hence, we have used the ACS712. [?] 32
  33. 33. 4.0.14 Flow Chart chart.JPG Figure 35: Flow chart of design system The piezoelectric discs are arranged in the mechanical system which upon force produces electricity which goes through the energy harvesting circuit and stores the electricity in a supercapacitor which in turn will light an LED. The output from energy harvesting system will go into the power monitoring system through the voltage divider circuit and through the current sensing module back to be read into the Arduino Uno Rev-3 which in turn will send the data to the LCd for displaying to output the voltage, current, power in W and Wh. 33
  34. 34. 4.0.15 FSM Figure 36: Finite State Machine for System The state machine describes how the system will work from each state to state and each subsystem to subsystem. The idle state is the Piezo mechanical system and this given pressure will act as output 1 and send the signal to the harvesting system which will get input 1 if input is 0 the idle state will be actuated again. From the energy harvesting system output of 1 is given the the battery in our case the capacitor if input is zero the system will be actuated again for output of 1 to capacitor which gives output of 1 to the LED. 34
  35. 35. 4.1 Arduin Code #include <LiquidCrystal.h> double PinV = 2; double PinI = 3; int time; double Voltage; double Current; double Power; double PowerWh; LiquidCrystal lcd(12,11,5,4,3,2); void setup(){ Serial.begin(9600); lcd.begin(16,2); time = 0; Voltage =0; Current =0; Power =0; PowerWh = 0; } void loop(){ Voltage = (analogRead(PinV)*12.764)/218; if(Voltage <0){ Voltage = 0; } Current = ((514-analogRead(PinI))*27.03/1023); if (Current <0){ Current = 0; } Power = Voltage *Current; PowerWh = (Power /3600) +PowerWh; Serial.print("VOLTAGE : "); Serial.print(Voltage); Serial.println("Volt"); Serial.print("CURRENT :"); Serial.print(Current); Serial.println("Amps"); Serial.print("POWER :"); 35
  36. 36. Serial.print(Power); Serial.println("Watt"); Serial.print("ENERGY CONSUMED :"); Serial.print(PowerWh); Serial.println("Watt-Hour"); Serial.println(""); // print the next sets of parameter after a blank line delay(2000); lcd.setCursor(0,0); lcd.print(" "); lcd.setCursor(0,0); lcd.print(Voltage); lcd.print("V"); lcd.setCursor(8,0); lcd.print(Current); lcd.print("A"); lcd.setCursor(0,1); lcd.print(" "); lcd.setCursor(0,1); lcd.print(Power); lcd.print("W"); lcd.setCursor(8,1); lcd.print(PowerWh); lcd.print("Wh"); delay(1000); } ˆ # include< LiquidCrystal.h > - This code will include the library for the Liquid Crystal because we are using an LCD for displaying the voltage, current, and power. ˆ double PinV = 2; double PinI = 3; int time; double Voltage; double Current; double Power; 36
  37. 37. double PowerWh; This will initialize all our variables. PinV which will be connected on the arduino to Analog A2 and PinI to analog A3 pin and these are the pins for reading the voltage and current from the circuit. ˆ LiquidCrystal lcd(12,11,5,4,3,2); - This line will prepare the arduino to know the pin connections :12,11,5,4,3,2 are the ones the lcd will connect to and initialize. ˆ void setup(){ Serial.begin(9600); lcd.begin(16,2); time = 0; Voltage =0; Current =0; Power =0; PowerWh = 0; } void loop(){ Voltage = (analogRead(PinV)*12.764)/218; if(Voltage <0){ Voltage = 0; } Current = ((514-analogRead(PinI))*27.03/1023); if (Current <0){ Current = 0; } Here the code is ready for startup with the funciton void setup() and the lcd is initialized where it will begin and where the display will output data. lcd.begin(16,2); The variables are all initialized to 0. ˆ void loop(){ Voltage = (analogRead(PinV)*12.764)/218; if(Voltage <0){ Voltage = 0; } Current = ((514-analogRead(PinI))*27.03/1023); if (Current <0){ Current = 0; 37
  38. 38. } Here the code runs into a loop where the Voltage and Current are initial- ized and will be displaying these two variables constantlt with a delay of 2 second ˆ ˆ Power = Voltage *Current; PowerWh = (Power /3600) +PowerWh; This equation is for outputting the power values in W and Wh from the Votlage and Current values onto the display. ˆ Serial.print("VOLTAGE : "); Serial.print(Voltage); Serial.println("Volt"); Serial.print("CURRENT :"); Serial.print(Current); Serial.println("Amps"); Serial.print("POWER :"); Serial.print(Power); Serial.println("Watt"); Serial.print("ENERGY CONSUMED :"); Serial.print(PowerWh); Serial.println("Watt-Hour"); Serial.println(""); // print the next sets of parameter after a blank line delay(2000); This is the code for outputting the values onto the serial monitor. lcd.setCursor(0,0); lcd.print(" "); lcd.setCursor(0,0); lcd.print(Voltage); lcd.print("V"); lcd.setCursor(8,0); lcd.print(Current); lcd.print("A"); lcd.setCursor(0,1); lcd.print(" "); lcd.setCursor(0,1); 38
  39. 39. lcd.print(Power); lcd.print("W"); lcd.setCursor(8,1); lcd.print(PowerWh); lcd.print("Wh"); delay(1000); } This code will print onto the LCd the values of the Voltage, Current, Power in W and Wh. The calculations and readings are taken from the arduino and the LCD reads this part of the code and outputs it onto the LCD. 4.1.1 Calculations Calculations for the Arduino part are as follows: Since the voltage input fromt he piezo electric system ranges from 0-50V the voltage needs to be stepped down in order to be inputed to the Arduino which takes only 5V maximum. Hence, A voltage divider calculation is needed for 50V to be converted to 5V. Figure 37: Voltage Divider circuit R1 R2 = R1∗R2 R1+R2 = 1MΩ∗100KΩ 100KΩ+1MΩ = 90909.09090909091 Ω Voltage = (analogRead(PinV)*12.764)/218; The analog reading needs to be converted to digital and this is done by mul- tiplying the voltage divider output by the ration which is from the A2 input and the R1 resistor which comes up to around 12.764 and this is divided by 218 because 1023/5 = 204.6 and the closest approximation is 218 because we need a digital output of 5V. For the current sensing part calculations need to be done for analog to digital conversion: 39
  40. 40. Current = ((514-analogRead(PinI))*27.03/1023); The calculation is done of 514-analogRead(PinI) because when the input is 0 the current sensor gives an output of 2.55V and in digital half of 5V needs to be subtracted so it is 514. It is multiplie by 27.03 since the sensitivity is 0.185 V as per the datasheet 5V is divided by 0.185V and this gives 27.03 and the whole thing is divided by 5V for a digital output to be given out. 40
  41. 41. 5 implementation 5.1 implementing the electrical system: 5.1.1 implementing the power generating stage: On the mechanical structure we place 12 buzzers on the lower layer upon the holes, each disk has another disk replaced opposite to it to make it easy when we want to connect them in series by connecting the positive side of each buzzers to the negative side of the other buzzer then we connect the groups in parallel as shown in38. The negative side of each piezo will be the negative output from the bridge and the positive side will be the positive side of the bridge rectifier since we are going to connect each buzzer to diodes bridge. When we apply a pressure on the upper layer the bolts press the piezo discs at the same time, the piezo disks will convert the pressure to electrical power. Figure 38: replacing the piezo discs on the lower side of the mechanical system In picture 38 we can see the piezo discs replaced on the lower layer and each disk is connected to diodes bridge rectifier . And in order to increase the output voltage from the buzzers we connect each two disks in series but the output current from the piezo was very small so to increase the output current we connect the groups in parallel . Picture39 showing the mechanical system of the power generating stage. Picture 40 showing the lower layer with the piezo disks placed on it and the upper layer with the bolts fixed on it also we can see the springs between the upper and the lower layers. Picture38 showing when we apply the pressure on the upper layer we can see how the all bolts are pressing the piezo discs. 41
  42. 42. Figure 39: the mechanical system of the power generating stage Figure 40: the lower and the upper layers of the mechanical system 42
  43. 43. Figure 41: applying pressure on the mechanical system 5.1.2 implementing the power storing stage: 5.1.3 build bridge rectifier Instead of connecting the all the piezo buzzers directly together then connect to one diode bridge it was better Idea to connect each buzzer to bridge so we need 12 bridges, otherwise the output from each piezo may cancel the output from the another piezo (the output from the piezo is sine wave so may the positive cycle may canceled by the negative cycle of the other piezo). The piezo buzzers provide us with very small power, so we use schottky diodes 42 that consume very small voltage to build our bridge rectifier we will need 4 diodes and connect them as following: 1. for each two diodes connect the negative side of one of them to the positive side for the another one. This will be the input side of the bridge 2. now the free unconnected positive side for one diode connect it to the other free unconnected positive side to the opposite diode, this will be the positive side of the bridge. 3. finally the free unconnected negative side for one diode connect it to the other free unconnected negative side to the opposite diode, this will be the negative side of the bridge. Picture42 showing the bridge rectifier that we built for each diode the side with line is the negative side 5.2 connect the piezo discs to the bridge After we built our bridge rectifier we have to connect the piezo discs to it and that can be done by connecting the negative side and the positive side to the input side of the bridge, as shown in picture 44 , we can see the red wire of the 43
  44. 44. Figure 42: schottky diodes [?] Figure 43: diode bridge 44
  45. 45. piezo (positive wire) connected to the input side of the bridge the same thing to the black wire(negative wire). Figure 44: connect the piezo discs to the diode bridge 5.2.1 connecting the piezo discs in parallel and series For each two piezo discs connect their one positive side of the bridge to the one negative side to the second bridge, this will be the series connection between the piezo buzzers and that will increase the output voltage, then connect the free unconnected positive sides of the all diode bridges together and the free unconnected negative sides of the all diode bridges together this will be the parallel connection, tha aim of the parallel connection is to increase the output current. See picture45 5.2.2 connecting the smoothing capacitor , regulator and the storing super capacitor Finally to finish the storing stage we have to connect smoothing capacitor 100f ( to smooth the output rippled voltage from the bridge rectifier) a cross the bridge rectifier and connect the positive side to the input of the regulator the output 45
  46. 46. Figure 45: connecting the piezo discs in parallel and series of the regulator is connected to another 100f capacitor the aim of the second capacitor is to filter and remove any noise or ac frequency in the regulator output. The middle pin of the regulator is grounded, finally we connect the super capacitor to store the output voltage, picture46 is showing the connected component for the storing stage. Figure 46: power storing circuit 5.2.3 implementing the load circuit: We used a LED as a load, this led is connected in series with a rheostat and switch. The aim of the rheostat is to adjust and control the flowing voltage to 46
  47. 47. the LED, and the switch is used to turn off and on the circuit. Picture 47 is showing the load circuit. Figure 47: power storing circuit #include <LiquidCrystal.h> double PinV = 2; double PinI = 3; int time; double Voltage; double Current; double Power; double PowerWh; LiquidCrystal lcd(12,11,5,4,3,2); void setup(){ Serial.begin(9600); lcd.begin(16,2); time = 0; Voltage =0; Current =0; Power =0; PowerWh = 0; } void loop(){ 47
  48. 48. Voltage = (analogRead(PinV)*12.764)/218; if(Voltage <0){ Voltage = 0; } Current = ((514-analogRead(PinI))*27.03/1023); if (Current <0){ Current = 0; } Power = Voltage *Current; PowerWh = (Power /3600) +PowerWh; Serial.print("VOLTAGE : "); Serial.print(Voltage); Serial.println("Volt"); Serial.print("CURRENT :"); Serial.print(Current); Serial.println("Amps"); Serial.print("POWER :"); Serial.print(Power); Serial.println("Watt"); Serial.print("ENERGY CONSUMED :"); Serial.print(PowerWh); Serial.println("Watt-Hour"); Serial.println(""); // print the next sets of parameter after a blank line delay(2000); lcd.setCursor(0,0); lcd.print(" "); lcd.setCursor(0,0); lcd.print(Voltage); lcd.print("V"); lcd.setCursor(8,0); lcd.print(Current); lcd.print("A"); lcd.setCursor(0,1); lcd.print(" "); lcd.setCursor(0,1); lcd.print(Power); lcd.print("W"); 48
  49. 49. lcd.setCursor(8,1); lcd.print(PowerWh); lcd.print("Wh"); delay(1000); } Figure 48: Arduino circuit for Displaying values The implementation of this code and connecting the circuit altogether gave a lot of problems. The problems starts with input voltage since it is varying and not a constant voltage obtain a voltage divider suitable for the system was critical. The other issue was due to the voltage problem one of our LCD’s had burnt out and would not display the correct values or characters on the screen. The code gave a lot of errors during compiling, there were problems uploading the code due to configuration of the ports. But the code and connections after revision gave us the results we needed for our system as a whole to work. 49
  50. 50. Figure 49: Software implementation Figure 50: Software implementation 50
  51. 51. 5.3 Project Management Figure 51: Gantt chart progress for system As can be seen from the Gantt chart the only change from the progress report to the final design report is the added timing for testing for a duration of about 30 days from 27 September to November 10. 51
  52. 52. 5.3.1 Assembling the all systems: Finally we connect the all systems together, we connect the mechanical part with the piezo ceramics to the storing circuit, the storing circuit is connected to the load circuit as shown in pictures 52 refb13. Figure 52: Assembling the all systems 5.3.2 Problems that we face during the work 1. before getting the piezo buzzers we ordered a square shape piezo material 54, those piezo was very expensive about 400dh for each54, when we test it we shocked that the output from it is less than 0.1mw, so we need more piezo sheets , also it is only can generate power when we vibrate it, and that is not consistent with our project, where we need to generate power when we press the sheets, this mistake teach us to be very careful in the future when we want to order anything. 2. in the first time we built our rectifier bridge from normal diodes , and when we connect it to the piezo disks , the output voltage dropped to zero, that’s why we used the schottky diodes that have very small voltage drop. 6 results 6.1 results of testing circuit Before we build the final demo we built a simple design testing circuit to test the properties of the piezo elements and check it if they are able to generate 52
  53. 53. Figure 53: piezo layer with storing and load circuits Figure 54: piezo material that we order 53
  54. 54. enough power and understand the relation between the pressure, voltage, and the size of the piezo. The next pictures is showing the results of the testing circuit Picture 55 showing the testing circuit are connected in parallel to one rectifier bridge. Figure 55: testing circuit Picture 56 is showing the output from the testing circuit, the piezo buzzers was new so they were able to give us 54.6v with one press. Picture 57 showing the testing circuit while it charging the capacitor. In one minute we were able to charge the capacitor to 10.06v 6.2 results from the main demo After we implement and built our demo we were able to generate electrical power and store it in super capacitor then supply it to the load, in other words the project was very successful and meet the objects. The next pictures are showing the results of our demo We test the piezo elements to see how much voltage we can get from it picture59and ?? showing the output voltage from the ceramics: Picture 59 showing the output from the piezo squared ceramic, we can notice how is the output is sin wave and very small output power , and we need to vibrate the sheet to get the output. Picture ?? showing the output waves on the oscilloscope from the piezo buzzer discs, the output is sin wave and the maximum voltage was about 10 v this volt we get it by clicking the discs continuously. Picture?? showing the output voltage on the oscilloscope when we apply pressure on the mechanical system, this improve that we were able to generate 54
  55. 55. Figure 56: output from the testing circuit Figure 57: testing circuit while it charging the capacitor 55
  56. 56. Figure 58: output from the piezo squared ceramic Figure 59: output waves on the oscilloscope from the piezo buzzer discs 56
  57. 57. a power from the piezo sheet. Figure 60: output voltage on the oscilloscope when we apply pressure on the mechanical system Picture61is showing the rectified output from the bridge rectifier in the me- chanical system, here we can see how the current has one direction only after it rectified. Picture62 is showing the output that is charging the super capacitor, this is output is coming from smoothing circuit. Picture63 is showing the multimeter value before the system start charging the capacitor here we can see the capacitor is discharge Picture64 is showing the multimeter value after the system start charging the capacitor here we can see the capacitor is charged tell 10.22v this picture improve that we were able to charge a super capacitor. Picture 65 showing the super capacitor is discharging and supplying the voltage to the load , the multimeter value is dropped from 10.22 to 9.33. Picture66 shows the led glows after we turn on the switch. The lime of glowing depend on the rheostat value when it zero the led only sparks one time and then turned off, but when we increase the value of the resistance, the led works for long time but with low brightness. 57
  58. 58. Figure 61: output from the piezo squared ceramic Figure 62: output that is charging the super capacitor 58
  59. 59. Figure 63: multimeter value before the system start charging Figure 64: showing the multimeter value after the system start charging 59
  60. 60. Figure 65: super capacitor is discharging and supplying the voltage to the load Figure 66: led glows after we turn on the switch 60
  61. 61. Figure 67: Arduino Code Figure 68: Arduino Code 61
  62. 62. Figure 69: Arduino Code output on serial monitor Figure 70: Complete system working and displaying output 62
  63. 63. Figure 71: 3V at end of discharge completely and also voltage at which LED lights up Figure 72: 2minutes 22 seconds body weight on mechanical structure to charge capacitor to 10V 63
  64. 64. Figure 73: 4 minutes 2 seconds to charge capacitor to 10 V by hand Figure 74: 2 minutes 8 seconds to discharge from 10 V to 3V The final systems as shown in Figure is what we had by the end. We con- nected the input which is at the voltage divider and ground the negative part and this gives us output. The arduino is powered up by the USB cable to the laptop and the Arduino code is compile and uploaded to the microcontroller. Once the input from the system was given the output is shown on both the serial monitor and the LCD display. The input from the mechanical structure goes through a circuit as shown in Figure ?? The circuit goes through a rectifier circuit from each of the peizos in an array and it then goes into the energy har- vesting circuit where it is parallel with a capacitor for smoothing the voltages out and then a voltage regulator in order to a fixed voltage and then through a parallel capacitor network for smoothing out more and remove the noise. At the end of it it will go to another separate board which will have a rheostat which plays with the resistance which in turn will be a brightness meter for the LED and this capacitor will light up the LED. We managed to charge the capacitor 64
  65. 65. up to 10 V with the body’s weigh typically 60kgs for 2 minutes 22 seconds as shown in Figure 72 and by hand it takes 4 minutes 2 seconds as shown in Figure 73. The discharge time is 2 minutes 8 seconds to drop from 10 V to 3.5 volts as shown in Figure 74, 71 7 Conclusion and Future Work The conclusion of this report is that the proposed design system that was to light up a bulb through the use of piezoelectric discs with the pressure from vehicles on the roads was down scaled to a mechanical system with an array of piezo discs to receive pressure through ones body weight successfully charged a capacitor and lit up and LED. The project has worked in terms of the technical stages of charging up a battery and lighting a lamp just the source of pressure is a human not a vehicle and instead of piezo discs we proposed a piezo sheet implemented on roads. It could not be implemented on roads as we do not have enough resources are available to do so also more research is needed regarding road implementation. American piezo and other industries gave us a red flag for the use of piezo sheets on roads and other suppliers would not supply a few sheets to our group. With team coordination this design system has been a success. With the appropriate design made and division of work between the team members the design has been successfully carried out as each subsystem works perfectly and gives the readings and outputs that is needed for evidence of work. The problems is piezo is a new technology and the resources are not always readily available the other issue is the ouput is not a steady source of voltage or current hence, we have very low power. The power is in mJ because we have very low current output as it is not a stable source of energy they are peaks of energy which needs to be sampled and harvested and then outputted. Due to the lack of times, resources,a a flexible budget this could not be achieved. The future thought is to use a linear booster in order to step up the voltage and a voltage sampler in order to have a constant output not peaks of output which needs a lot of time to store. The application then for the future can be used for charging phones with every footstep, road implementation but these areas need a lot of research. 65
  66. 66. Figure 75: Schematic diagram on board for the power monitoring system 66
  67. 67. Figure 76: Schematic diagram on board for the power monitoring system 67
  68. 68. Figure 77: Schematic diagram on board for the power monitoring system 68
  69. 69. Figure 78: Schematic diagram on board for the power monitoring system 69
  70. 70. Figure 79: Schematic diagram on board for the power monitoring system 70
  71. 71. Figure 80: Schematic diagram on board for the power monitoring system 71
  72. 72. Figure 81: Schematic diagram on board for the power monitoring system 72
  73. 73. Figure 82: Schematic diagram on board for the power monitoring system 73
  74. 74. Figure 83: Schematic diagram on board for the power monitoring system 74
  75. 75. Figure 84: Schematic diagram on board for the power monitoring system 75
  76. 76. Figure 85: Schematic diagram on board for the power monitoring system 76
  77. 77. Figure 86: Schematic diagram on board for the power monitoring system 77
  78. 78. Figure 87: Schematic diagram on board for the power monitoring system 78
  79. 79. Figure 88: Schematic diagram on board for the power monitoring system 79

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