wpt finalprogressreport
TRANSCRIPT
WIRELESS POWER CHARGING SYSTEMBy
Ubong UdoessienTamim AlkhonainiNadeem Qandeel
Senior Design Progress Report
Submitted to:Advisor:
Dr. Aiping Yao
_________________________ Signature
Committee:
Dr. Glazos
_________________________ Signature
Dr. Petzold
_________________________ Signature
Department of Electrical and Computer EngineeringCollege of Science and Engineering
1
Abstract
Wireless power transfer is the transmission of electrical power from a source to an electrical load without the need of conducting wires or materials. The project can be done through magnetic coupling between copper coils. The technology of wireless power transfer is getting a particular interest from the industry due to it is numerous applications.
2
Table of Contents:
1. Introduction· Background · Problem Statement· Design Objectives · Design Specifications · Constraints
2. Design Methodology · Design Alternative· Research Concepts· System Level Design· Future Work
3. Testing · Accomplishments· Testing and Results
4. Budget
5. Schedule
6. Conclusion· Summary· Lessons Learned
7. References8. Appendices
3
List of Figures
Figure 1 Transmitter Coils.............................................................................................................................7Figure 2 Receiver Coils.................................................................................................................................8Figure 3 ATmega328.....................................................................................................................................9Figure 4 FSR 406.........................................................................................................................................10Figure 5 A1 design schematic......................................................................................................................11Figure 6 Coil Arrangement for Wireless Inductive Power Transmission System.......................................12Figure 7 Resonant Coupled Windings with Resonant Capacitors...............................................................13Figure 8 Impedance Matching of a coupled circuit.....................................................................................14Figure 9 Qi Logo..........................................................................................................................................14Figure 10 Block diagram of system configuration......................................................................................15Figure 11 Sensor simulation circuit.............................................................................................................17Figure 12 Standalone ATMEGA328...........................................................................................................18Figure 13 PWM signal before filtering........................................................................................................20Figure 14 Two PWM signals filtered and going to transmitter...................................................................21Figure 15 serial communication monitor from microcontroller to PC........................................................22Figure 16 LCD screen..................................................................................................................................23Figure 17 LED indicators.............................................................................................................................24Figure 18 PWM signals with 80 KHz and 13V Pk-Pk................................................................................25Figure 19 LT Spice simulation of receiver circuit.......................................................................................26Figure 20 DC results....................................................................................................................................26Figure 21 Project expenses..........................................................................................................................29Figure 22 Work Schedule............................................................................................................................30Figure 23 Gantt chart...................................................................................................................................31
4
1. Introduction
1.1 Background
Wireless power transfer is the transmission of electrical power from a source to an
electrical load without the need of conducting wires or materials. The possible applications of
wireless power systems extend from wireless charging of phones and other consumer devices to
higher power applications like electric vehicles.
Wireless power transfer is getting particular interest from the mobile phone and the
electric vehicle industry. The industry realizes the demand for wireless power charging where
mobile devices can be charged without the need for connecting wires.
Wireless energy transfer has been around for some time since the inventions of Nicola
Tesla in the late 1800’s. Now there is widespread interest in finding suitable applications in
consumer products. The most common and probably the oldest consumer application of wireless
energy transfer can be found in the electric toothbrush.
Essential to the endorsement of wireless power transfer by consumers and industry as a
means of powering devices is the efficiency of the power transfer when compare to a convention
plug and socket power supply.
1.2 Problem Statement
The aim of the project is to produce a demonstration of wireless power system for
charging a mobile phone and illustrate how magnetic coupling can be used to transfer energy
wirelessly.
1.3 Design Objectives
The overall purpose of the project is to demonstrate how a wireless power system works
for charging a mobile phone or multiple phones. To illustrate how magnetic coupling work and
how resonant magnetic coupling could improve the level of power transferred at a distance.
5
Most of the project research will consist of; conducting experiments in different circuit
designs to achieve a wireless power system and improve on the performance, the addition of the
microcontroller element to be able to control specific tasks that are unique to this project. The
factors and implementations that allow for wireless charging of a mobile phone lithium battery
will be researched. It is of most importance that the research and any following lab
demonstration comply with the Qi standard.
The Qi standard will be the foundation on which any final demonstration or prototype
will be developed. The Qi standard identifies the coil design, coil size, shielding and positioning.
The wireless charging project should explore the two different wireless charging outlines in the
Qi standard, guided positioning and free positioning.
1.4 Design Specifications
The key components that will bring about the success of this project include; the
transmitter circuit, the receiver circuit, the copper coils, and the micro-controller. To each of
these components a set of specifications that allows them to be beneficial to the need of the
project.
The transmitter coil has to have certain dimension and so does the receiver coil, to ensure
that mutual magnetic induction occurs between the two coils. Just as mutual inductance is
witnessed in a transformer it operates in this project under the same principle, as the current
flowing in the transmitter coil induces a voltage in the adjacent receiver coil, which in turn
causes current flow in the second coil.
Figure 1 Transmitter Coils.
6
Table 1 Transmitter Coil Parameters.
Parameter Symbol Value
Outer diameter do 43+-0.5mm
Inner diameter di 20.5+-0.5mm
Thickness dc 2.1+-0.5mm
Number of Turns per Layer N 10
Number of Layers – 2
The receiver coil is a key component in a successful and efficient design of a Qi-
compliant receiver things to be considered in the design is the shield, wire gauge and number of
turns.
Figure 2 Receiver Coils.
7
Table 2 Receiver Coil Parameters
The ATmega328 chip of the Arduino Uno has 14 digital input/output pins (of which 6
can be used as PWM outputs), 6 analog inputs, on the breadboard connected to the chip will be a
16MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button
to allow the use of the microcontroller with full functionality.
Figure 3 ATmega328.
8
Table 3 Arduino Uno Specifications.
Parameter Value
Input Voltage 7V - 12V
Operating Voltage 5V
Digital Pins 14 (6PWM)
Analog Pins 6
Flash Memory/EEPROM 32KB/1KB
The FSR used is a force sensing resistors, or FSRs, are robust polymer thick film (PTF)
devices that exhibit a decrease in resistance with increase in force applied to the surface of the
sensor. It allows the user to detect physical pressure, squeezing and weight. They are simple to
use and low cost.
Figure 4 FSR 406.
9
1.5 Constraints
Few constraints have risen since the proposal of the project, those constraints have been
in the areas of future communication work and wireless charging including both the transmitter
and the receiver.
The ultimate goal for the transmitter unit is to achieve a high voltage and about 700mA at
its end, but the first couple of transmitter circuits designed have failed to produce the wanted
outcome, one circuit schematic was the A1 design shown below.
Figure 5 A1 design schematic.
One of the challenges in this circuit is that it required four high frequency PWM signals
that the microcontroller had troubles providing, in addition to the occurrence of cross conduction
which was a result of the PWM signal being on at the same time rather than one is off while the
other is on, along with other many problems this was the reason for the circuit’s failure to
provide the expected outcome and rather it was supplying 2.4V with 0.1mA which is not enough
to transfer to the receiver and charge the phone. A solution to the problem mentioned above was
to switch to the half bridge circuit that requires only 1 PWM signal and its toggle signal.
Another constraint we had was in the initial proposal to use the Bluetooth capability in
the phone for communication medium, but the Bluetooth requires prior pairing between each
phone, in addition to the fact that communication can’t be established when the phone is off
because Bluetooth will be off as well. A solution to this problem was to switch to NFC
technology which requires no pairing between the tag and the reader in TX and Rx unit.
10
Also the tag in the receiver unit doesn’t require power to turn on which makes it perfect for the
dead phone situation.
2. Design Methodology
2.1 Design Alternative
Wireless power transfer by inductive coupling consist of a transmitter coil and receiver
coil whereby both systems forms a system of magnetically coupled inductors. An alternating
current on the transmitter coil generates a magnetic field which induces a voltage in the receiver
coil. The induced voltage, conditioned through the receiver circuit can be used to power a device.
The efficiency in power transfer is dependent on the coupling factor (k) between both
primary coil (L1) and secondary coil (L2) and their quality factor (Q). K, the coupling is a
function of the distance between the inductors (z) and its ratio (D2/D). The coupling factor is
determined as follows:
Where, M is the mutual inductance of the primary coil (Lp) and secondary coil (Ls).
11
Figure 6 Coil Arrangement for Wireless Inductive Power Transmission System
The quality factor (Q) which is the ratio between the inductance of a coil, its resonant frequency
(w) and its resistance (R) is expressed as follows:
Resonant Inductive Coupling.
Resonant circuits are used to enhance the inductive power transmission for systems with
low coupling factor. To ensure effective coupling between both transmitter and receiver side, it is
important that both sides resonate at the same frequency. An LC circuit which is also called a
tuned circuit consist of inductance of the coil (L) and a resonant capacitor (C). This circuit stores
energy oscillating as the circuit’s resonant frequency (fr). This relationship is determined as
follows:
12
Figure 7 Resonant Coupled Windings with Resonant Capacitors
Reflected Impedance.
Impedance matching is a good way to optimize inductive coupling by ensuring that the resonant
tank capacitance is implemented at the secondary side by adding a capacitor either in parallel or
in series. Fig 6 shows a typical circuit with matching impedance configuration.
Figure 8 Impedance Matching of a coupled circuit.
2.2 Research Concepts
Section 2.1 details the research concept employed for this project.
For this project, inductive coupling will be used to implement a wireless power transfer.
The initial goal for this project involved transmitting power over a distance of 2m. However,
after careful consideration of safety concerns, it was determined to build a system with a shorter
range that can still power a mobile device. The design chosen followed the Qi standard which
allowed for power transfer of 5W.
2.3 System Level Design.
This project was implemented using the Qi standard which is a product of the Wireless Power
Consortium whose main goal of was set a standard for wirelessly powering mobile devices. The
13
Qi standard has been adopted by major phone companies as the preferred wireless transfer
standard. Hence, in implementing this project, the Qi standard design employed is the A1 Power
Transmitter design A1. The Qi standard allows the developer design freedom in implementing
the transmitter and receiver circuit.
The system consists of three main parts:
1. Transmitter unit.
2. Receiver unit.
3. Control and Communication Unit.
Below block diagram illustrates the system configuration of the wireless power transfer
implemented.
Transmitter Circuit.
14
The transmitter unit henceforth called the base-station consist half-bridge inverter and
primary coil. The inverter converts the step down DC input to an AC waveform that drives a
resonant circuit which consist of the primary coil plus a series capacitor. The primary coil will
have a resolution of 5mA. Operating frequency range of the inverter will be between 110 - 205
KHz.
Receiver Circuit
The Receiver unit consist of a dual resonant circuit, rectifier circuit, a communication
modulator and dc filter. The dual resonant circuit consist of secondary coil (Rx coil), series and
parallel capacitances to enhance the power transfer efficiently. The rectification circuit will
provide a full wave rectification of the AC from the Rx Coil using a full bridge configuration to
provide smoothing while the communications modulator will control the primary coils current
and voltage. A voltage regulator (LM7805C) will be used to regulate the receiver’s output to 5
Volts.
Control/Communication Unit.
The communications and control unit comprises the digital logic part that receives and
decodes messages from the power receiver, executes the relevant power control algorithms and
protocols, drives the frequency of the AC waveform to control the power transfer in the Tx unit
and communications modulator on the Rx unit.
The way the communication/control unit interacts with the overall system starts with the
FSR sensor that detects the presence of a phone device on its surface, this is done by employing
a voltage divider using the sensor and a 10K ohm resistor. As the phone is placed on the sensor,
the equivalent resistance decrease from infinity to a smaller value that allows current to flow in
the 10K ohm resistor causing a voltage drop that is picked up by the microcontroller and used as
a threshold to identify the presence of a cell phone device.
15
Figure 11 Sensor simulation circuit
After the placement of a phone the microcontroller generates a PWM signal that is used
to switch the MOSFET’s in the TX unit to initiate the charging cycle and depending on what
sensor on the pad out of the four sensor is being used an LED lights.
We have simulated the rest of the three sensors using appropriate resistance value until
we purchase the rest of the sensors. The microcontroller Arduino UNO which controls the
system has been used as a standalone chip with few electronic components such as a voltage
regulator, 16MHz crystal and small capacitors and a reset button for the system.
16
Figure 12 Standalone ATMEGA328
The LCD’s role in the control part is to simulate it is behavior in the final stage of the
project which is to portray information relevant to the phone ID and charging state, so at this
stage after the phone charged you click on one of the buttons to show one of the phones
information.
2.4 Future Work
The long term goal will be to expand the charging station to charge multiple phones by
replicating the original circuit of the transmitter circuit and adding more coils, so it can charge
four phones at the same time, taking into consideration the necessary power requirements to
integrate a bigger transmitter station. Moreover, we will include a communication unit that will
allow the transfer of data from the receiver unit attached to the phone to the microcontroller in
the transmitter unit, so that the output of the transmitter circuit is monitored and regulated upon
need in addition to processing the data and displaying it on a LCD screen to notify the user of
phone’s charging status.
17
In more details we would like to increase the output of the transmitter current to 1A so
that we can also charge bigger electronic devices such as IPad etc. Also adding a protective
feature that will stop the transmitter from continuing to charge the phone when the phone reaches
a full charging percentage.
To achieve these goals we will be relying on heavy research in the areas of
communication and small power distribution systems. In addition to simulations to optimize the
performance of the transmitter circuit by improving the resonant coupling circuit, reducing losses
in the circuit and any form of overheating.
3. Testing
3.1 Accomplishments
1) Transfer 5W power between the transmitter and the receiver units using inductive
coupling.
2) Charge one phone wirelessly using inductive coupling.
3) Used resonant coupling technique using the receiver, function generator and coils to light
an LED.
4) Initialize and program ATMEGA328 chip standalone to control the system and generate
a range of high frequency PWM signal with controlled duty cycles
5) Program an LCD to display output and control output using buttons.
6) Implement the use of a sensor in the system to detect phones on the base station.
3.2 Testing and Results
Testing has a great importance in this project, all significant progress occurred when
simulation and calculations agreed, to give a successful practical testing in the lab.
18
A. Controls and Communication
1. PWM Generation:
One of the key components to this project is the generation of the PWM signal. PWM
signal controls the switching frequency of the half bridge inverter circuit. Two PWM signal will
be generated from the Arduino microcontroller each signal will be sent to each of the MOSFET’s
in the half bridge circuit in the transmitter.
In the lab using an oscilloscope the PWM signal generated can be measured and
displayed on a channel as can be seen in figure below.
Figure 13 PWM signal before filtering
19
In this figure, 3 PWM signals are generated and one of them is phase shifted as it shows
for testing purposes. Now the Arduino can generate up to 6 PWM signals from 6 pins, each pin
has a predefined frequency that is set by the chip designers.
To be able to change the frequency of the PWM signal generated from the chip like we
need to do in this project, we have to play with timers of the Arduino, since we also need to
generate high frequency signals that ranges from 100KHz to 200KHz, to achieve that, a new
code has to be written that changes that changes the registers and only then the Arduino can
generate up to 4 PWM’s instead of 6. The reason is each 2 PWM’s are linked to a timer and one
of the timers controls the clock of the chip hence control the delays functions so that timer
should remain unchanged.
In the figure below we can see a clean filtered version of 2 PWM signals with 200 KHz
frequency, 50% duty cycle and 0.9% noise.
Figure 14 Two PWM signals filtered and going to transmitter
2. Weight Sensor
20
The FSR is a device that allows the detection of a physical object that is placed on it. It
has a 4cm x 4cm active area for detection and can detect from 10g to 1kg of weight.
The way this works is that as the resistance of the FSR decreases, the total resistance of
the FSR and the pull down resistor decreases from about 100Kohm to 10Kohm. That means that
the current flowing through both resistors increases which in turn causes the voltage across the
fixed 10K resistor to increase.
Best way to test it is to connect it across an ohmmeter and apply weight and notice how
the reading changes on the meter. For further testing using the Arduino a sketch was to made to
take the analog voltage reading and use that to determine how bright the red LED is. The harder
you press on the FSR, the brighter the LED will be! Connecting the LED to a PWM pin.
In the figure below another sketch was made to measure the voltage across the resistor,
analog reading of the Arduino, FSR resistance and measure the approximate Newton force
measured by the FSR.
21
Figure 15 serial communication monitor from microcontroller to PC.
Eventually the sensor was connected to the circuit and Arduino successfully and triggered
the generation of the PWM signal when a phone is placed on it.
3. LCD
22
The LCD used is an Omnix 16x2 LCD. It will be used to display phone information and
battery charge percentage. First step was to test the LCD output by displaying characters on it
using the Arduino to program it, then to test the backlight of the LCD and make it brighter using
a potentiometer and last step was to test the buttons connected to the LCD to bring new
information to the screen.
Figure 16 LCD screen.
In a similar photo to the one above, the LCD display shows the following the message;
“Press a button to show phone” as the user clicks a button out of the four button, information of
the corresponding phone would show stating the phone-number and the battery charging
percentage. In the program running the LCD, the change in battery charge percentage is
simulated by sending a different number every 3 seconds to update the phone charge.
4. LED Indicators
23
Since the base station can host four phones simultaneously, there are four phone light
indicators each indicator corresponds to one of the four charging pads, as each phone charges an
LED indicator needs to light to show that for example phone 1 is being charged. Once the phone
has been removed from the base station the LED turns off. This process is achieved with the help
of the sensor and microcontroller as the sensor tells the MC that a phone is place, which in return
turns the LED on.
Figure 17 LED indicators
As shown in the picture the light green on the most left represents that phone 4 is
charging and the second green light to the right shows that phone 2 is charging. The two red
lights in the center represent the 2 PWM signals the microcontroller is generating.
B. Transmitter Unit
The transmitter circuit design implements a half-bridge inverter to drive the primary coil
and the series resonant capacitor. Design specification A1 identifies an input voltage of 19±1 V
to the half bridge inverter. The operating frequency of the half bridge inverter, fop is chosen
between 110 kHz and 175 kHz with a duty cycle of 50%. For testing purposes, 77 KHz operating
frequency was used for testing purposes. The 5V Pulse Width Modulator (PWM) signal was
provided by an Arduino Uno.
24
An half-bridge driver IC (IRS2103I was used to amplify the 5V PWM to at least 10V to drive the
n-channel MOSFET (FQA55N25) which requires a 10V gate voltage with a 5V gate threshold
value to turn on. The voltage supply for both the driver and n-channel MOSFET was
C. Receiver Unit
1. Using function generator as an input:
Table 4 Function generator parameters
Wave Frequency (kHz) Vpp (V) Current (A)
Sine 125 10 0.1
The receiver unit was tested using a function generator as an input with the parameters
indicated above. Since the function generator cannot provide enough current, the output power of
25
Figure 18 PWM signals with 80 KHz and 13V Pk-Pk.
the receiver unit is not high enough to charge a phone. The output current is 0.03 mA and the
output voltage is 4.9 V.
Figure 19 LT Spice simulation of receiver circuit.
Figure 20 DC result
2. Using inductive coupling:
The receiver unit was tested using inductive coupling between the transmitter and
receiver units. At this point, the transmitter unit can provide enough current to charge a phone.
The output current is 0.45 A and the output voltage is 4.8 V.
3. Testing a phone
26
An iPhone 4s was tested by connecting it to the receiver unit, where the power was
transferred to the receiver unit using inductive coupling. The phone was connected to the
receiver unit for approximately 30 minutes to test the charging percentage.
Table 5 Battery percentage
Time (Hr) Battery Percentage (%)
04:25 PM 45
04:30 PM 48
04:45 PM 59
04:55 PM 65
4. Budget
The cost for our project is pretty reasonable, we have spent more money than we should
in the first semester due to experimenting on different parts to see which gives best result and not
exactly knowing what best meets our needs. For the second semester, our budget will be much
smaller since we already know what we want and we have bought most of the needed parts this
semester.
27
Figure 21 Project expenses
28
5. Schedule
We are mostly on schedule for our project but a little behind in the testing part to
increase our charging system’s performance, by the end of the first semester we would have
achieved big part of the controls and have demonstrated the operation of wireless power transfer
to charge one phone.
As for next semester we will investigate how to charge more than one phone and add the
communication capability to our project to allow a more interactive charging system take place.
29
Figure 22 Work Schedule
30
Figure 23 Gantt chart.
6. Conclusion
6.1 Summary
Some project progress has been made to this day. As is it can be seen from the work
mentioned above, simulation and lab experimentation. We have been able to achieve all our
goals for this semester including having a comprehensive prototype system to what our product
would behave and look like. The lab work demonstrates system integration of controls,
programming and wireless power transfer in its more basic form and it is hoped that through
good research, simulations and experimentation to take the project from there and enhance the
circuitry to charge a mobile phone wirelessly.
31
6.2 Lessons Learned
1) Weekly meeting and constant communication with our project advisor were
essential to the completion of this task.
2) We gained a lot of experience from working on our project and found the progress
presentation as an essential exercise for working in the real world.
3) Research and reading the Qi standard has been a valuable insight on how to starts
tackling the project.
4) Team work was a great experience and a helpful way to achieve this project.
5) Most important lesson learned of all was the time spent in the lab, the opportunity
to use and improve our engineering problem solving skills has been a key to
solving the problems encountered.
32
7. References
1) The Qi interface specification. “System Description Wireless Power Transfer Volume
I: Low Power Part1: Interface Definition”. Internet:
http://www.wirelesspowerconsortium.com/blog/11/qi-specification-available-for-download
[June. 1,2013]
2) Power By Proxi. “Wireless Charging”. Internet: http://powerbyproxi.com/wireless-
charging/
3) Instructables. “Inductive Power Transfer”. Internet: http://www.instructables.com
[July 5, 2008]
4) Brad Molen. “Engadget Primed:How wireless and inductive charging works”.
Internet: http://www.engadget.com/2011/06/24/engadget-primed-how-wireless-and-
inductive-charging-works/ [June 24, 2011]
33
8. Appendices
Code used to run the system
#include <PWM.h>#include <LiquidCrystal.h>#include <LCD16x2.h> #include <Wire.h>
LCD16x2 lcd;const int analog_pin = A0;const int analog_pin1 = A1;const int analog_pin2 = A2;const int analog_pin3 = A3;
int buttons;int buttons1;int buttons2;int buttons3;int buttons4;
//use pin 11 on the Mega instead, otherwise there is a frequency cap at 31 Hzint fsrAnalogPin = 0; // FSR is connected to analog 0int fsrAnalogPin1 = 1;int fsrAnalogPin2 = 2;int fsrAnalogPin3 = 3;
int fsrReading; // the analog reading from the FSR resistor dividerint fsrReading1;int fsrReading2;int fsrReading3;
long randNumber;String x;char y[50];
//int LEDbrightness;//int led11 = 11; //added//int led3 = 3; //addedint led9 = 9; // the pin that the LED is attached toint led10 = 10; //added//pin13, 12, 7, 4 is used
int brightness = 0; // how bright the LED isint fadeAmount = 5; // how many points to fade the LED by
int32_t frequency = 77000; //frequency (in Hz)
34
void setup(){ //initialize all timers except for 0, to save time keeping functions InitTimersSafe();
//sets the frequency for the specified pin //bool success9 = SetPinFrequencySafe(led9, frequency); bool success10 = SetPinFrequencySafe(led10, frequency); //added //bool success11 = SetPinFrequencySafe(led11, frequency); //added// bool success3 = SetPinFrequencySafe(led3, frequency); //added //if the pin frequency was set successfully, turn pin 13 on /*if(success9 && success10 && success3) { pinMode(13, OUTPUT); digitalWrite(13, HIGH); }*/ Wire.begin(); pinMode(analog_pin, INPUT); //pin A0 defined as input for LCD (pin 0 =fsr reading) pinMode(analog_pin1, INPUT); pinMode(analog_pin2, INPUT); pinMode(analog_pin3, INPUT); lcd.lcdClear(); pinMode(fsrAnalogPin, INPUT); pinMode(fsrAnalogPin1, INPUT); pinMode(fsrAnalogPin2, INPUT); pinMode(fsrAnalogPin3, INPUT); Serial.begin(9600); // We'll send debugging information via the Serial monitor //pinMode(led9, OUTPUT); //pinMode(led10, OUTPUT); randomSeed(1); }
void loop(){ fsrReading = analogRead(fsrAnalogPin); fsrReading1 = analogRead(fsrAnalogPin1); fsrReading2 = analogRead(fsrAnalogPin2); fsrReading3 = analogRead(fsrAnalogPin3); if(fsrReading) { pinMode(4, OUTPUT); digitalWrite(4, HIGH);
35
} else digitalWrite(4, LOW); if(fsrReading1) { pinMode(7, OUTPUT); digitalWrite(7, HIGH); } else digitalWrite(7, LOW); if(fsrReading2) { pinMode(12, OUTPUT); digitalWrite(12, HIGH); } else digitalWrite(12, LOW); if(fsrReading3) { pinMode(13, OUTPUT); digitalWrite(13, HIGH); } else digitalWrite(13, LOW);
// Serial.print("Analog reading = "); //Serial.println(fsrReading); //use this functions instead of analogWrite on 'initialized' pins // we'll need to change the range from the analog reading (0-1023) down to the range // used by analogWrite (0-255) with map! /*LEDbrightness = map(fsrReading, 0, 1023, 0, 255); // LED gets brighter the harder you press analogWrite(LEDpin, LEDbrightness); //try pwmWrite
delay(100);*/ int value = ( analogRead(analog_pin) + analogRead(analog_pin1) + analogRead(analog_pin2) + analogRead(analog_pin3) ) ; // for screen brightness it reads from pin 0 =A0 which gets input from fsr map(value, 0, 1023, 0, 255); lcd.lcdSetBlacklight(value); delay(100); randNumber = random(0, 100); //Serial.println(randNumber); x = String(randNumber); //Serial.println(x);
36
x.toCharArray(y, 50); //Serial.println(y); delay(3000); buttons = lcd.readButtons(); buttons1 = buttons & 0x01; buttons2 = buttons & 0x002; buttons3 = buttons & 0x004; buttons4 = buttons & 0x008; lcd.lcdGoToXY(1,1); if (!buttons) lcd.lcdWrite(" PRESS A BUTTON TO SHOW PHONES "); else if(!buttons1) { lcd.lcdWrite("PHONE1 320334111 IS CHARGED %"); lcd.lcdGoToXY(14,2); lcd.lcdWrite(y);} else if(!buttons2) { lcd.lcdWrite("PHONE2 320334222 IS CHARGED %"); lcd.lcdGoToXY(14,2); lcd.lcdWrite(y);} else if(!buttons3) { lcd.lcdWrite("PHONE3 320334333 IS CHARGED %"); lcd.lcdGoToXY(14,2); lcd.lcdWrite(y);} else if(!buttons4) { lcd.lcdWrite("PHONE4 320334444 IS CHARGED %"); lcd.lcdGoToXY(14,2); lcd.lcdWrite(y);} else lcd.lcdWrite(" PRESS A BUTTON TO SHOW PHONES ");
delay(100);
if ((fsrReading != 0 || fsrReading1 != 0) || (fsrReading3 != 0 || fsrReading2 != 0 )) { /* pwmWrite(led9, brightness);
brightness = map(fsrReading2, 900, 1023, 120, 120); /*brightness + fadeAmount;
if (brightness == 0 || brightness == 255) { fadeAmount = -fadeAmount ; } */
37
//delay(30); pwmWrite(led10, 175);
/* brightness = brightness + fadeAmount;
if (brightness == 0 || brightness == 255) { fadeAmount = -fadeAmount ; } //delay(30); /*pwmWrite(led3, brightness);
brightness = brightness + fadeAmount;
if (brightness == 0 || brightness == 255) { fadeAmount = -fadeAmount ; } //delay(30); */ }
else { //pwmWrite(led9, 0); pwmWrite(led10, 0); // pwmWrite(led3, 0); }
}
38