MSU Design Team 10

Final Report

12/9/2015

Dryer Moisture Sensor System

William Wang

Qi Luo

Ariadna Fernandez

James Fashoda

Thurakij Praditukrit

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Table of Contents

Executive Summary…………………………………………………………………..……………….....4

Acknowledgement…………………………………………………………………..………..5

Chapter 1 Introduction and Background Information……………………………….………6

1.1 Design Team 10 ,Whirlpool’s Engineers, and Facilitator

1.2 Whirlpool Project ­ Dryer Moisture Sensor System

1.3 Dryer’s Anatomy and Its Current Technology

Chapter 2 Exploring Solutions/Approaches…………………………………….............….9

2.1 Fast Diagram

2.2 Analysis by House of Quality

2.3 Power Generation’s Pugh Matrix

2.4 Wireless Communication’s Pugh Matrix

2.5 Budget Planning

2.6 Gantt Chart

Chapter 3: Technical Work…………………………………..………………………………………...19

3.1 Radio Frequency Process

3.1.1 Early Stages of MCU/Rf Components

3.1.2 MSP430G2553

3.1.3 Arduino Uno/Atmega328

3.1.4 Transmitter

3.1.5 Receiver

3.1.6 Antenna

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3.2 Power Generation Process

3.2.1 Faraday Flashlight

3.2.2 Power Generator

3.2.3 Voltage Regulator/Boost Converter

3.3 Sensor System

3.3.1 HIH­5030

3.3.2 LM35DZ

Chapter 4 Data Testings………………………………………………………………..……………....….…..39

4.1 Implementation of Device

4.2 Communication Testings

4.3 Sensor Testings

4.4 Power Testings

4.5 Prototype Performance vs. Design Specifications

Chapter 5 Design Issues

5.1 Safety Issue

5.2 Cost Issue

Chapter 6 Final Cost, Summary, and Conclusions………………………………………………..…….50

6.1 Project Successes

6.2 Final Cost in Product

6.3 Further Possible Improvements

Chapter 7 Appendix…………………………………………………………………………………56

7.1 Technical Roles, Responsibilities, and Work Accomplished

7.2 Literature and Website References

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7.3 Flowchart and Programming Codes

7.3.1 Transmitter Flowchart

7.3.2 Transmitter Code

7.3.3 Receiver Flowchart

7.3.4 Receiver Code

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Executive summary

The Whirlpool Dryer Sensor System is an upgrade for the current sensor system.

The goal of this project is to measure the temperature and moisture of the clothes in a

dryer using circuits inside the baffles of the dryer. This system also needs to have

self­power generating unit and wireless transmission unit. This system will provide more

reliable data to ACU in order to save the drying time and ensure the clothes are

completely dried. This design will increase the energy efficiency to make the dryer

consume less energy in each drying process.

Our team, ECE 480 Design Team Ten, will provide a prototype Dryer Sensor

System with reliable power generation method. In the drum, our system consists of

humidity sensor unit, wireless transmission unit and the power generation unit. After the

phase of data collection, research and testing, we use RF transmission and

revised­motor generator as our final design. The RF transmission is a low cost wireless

transmission method and the revised­motor generator will generate enough power for

the whole system as long as the drum is rotating. While the drum is working, our sensor

will pick up the data and will be sent to the ACU for further process. Our ACU and signal

receive unit will locate near the whirlpool’s control unit. The design has a

manufacturing cost of less than $5.00 for each component.

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Acknowledgements:

On behalf of ECE 480 Design Team Ten, we would like to thank the following people:

Our sponsors from Whirlpool Corporation, Josh Paul Fisher ,Mike Range and Cory Timothy Graves

for their advice and support in the development of our project

Our facilitator, Dr. Mukkamala

for his guidance and critique

MSU ECE Technical Services: Mr. Brian Wright and Mrs. Roxanne Peacock,

for supplying and ordering parts

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Chapter 1. Introduction and Background information

1.1 Design Team 10 ,Whirlpool’s Engineers, and Facilitator

Founded in St. Joseph Michigan in 1911 by Louise and Emory Upton, The

whirlpool corporation is an american multinational manufacturer of home appliances.

Initially starting out manufacturing washing machines, whirlpool soon gained the

reputation for their high quality of work and innovation which caught the eye of other

major retailers such as Sears, Roebuck & Co, as well as federal electric. Due to an

early success, Whirlpool began to grow in both sales and employees. Eventually the

company expanded their product line to include almost every household appliance that

families use today such as refrigerators, air conditioners, stoves and much more. Today

the Whirlpool name familiar to almost everyone around the world. Holding the title of a

fortune 500 company, Whirlpool has an annual revenue of approximately $20 billion,

employs more than 100,000 people and markets some of best known brands such as

Kitchenaid and Maytag. With the world headquarters located in Benton Harbor

Michigan, The engineering and research division of Whirlpool is constantly working to

improve current appliance models or develop a new breakthrough design. This year, the

company decided it needed to improve their dryer line, which was running on 20 year

old technology. Recently the company graciously decided to sponsor MSU’s department

of engineering and allowed undergraduate students to work with Whirlpool engineers to

get a first hand experience of working on new projects.

1.2 Whirlpool Project ­ Dryer Moisture Sensor System

Team 10 was given a project of creating a more accurate sensing for moisture

and temperature inside the dryer. Current sensors are located either in front or back of

the machine outside the drum depending on each model of the dryer. The problems

with the current positioning of the sensors are that the machine rarely reads data from

the laundry since there is only one of each sensor in the dryer. It does not collect data in

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more than one spot of the laundry load resulting in the accuracy drop of the output data.

Whirlpool does not specify which method we use to solve the problem but the only two

specifications that are of concern to them are to limit the cost of implementation to $5

and the design should last the duration of the dryer’s life.

1.3 Dryer’s Anatomy and Its Current Technology

There are some features that companies will take into account when designing a dryer. These features includes air movements, high temperature, and energy efficiency and low humidity. A dryer consists of several parts, seeFigure 1.3. The most important parts that relate to this project are the drum, baffles, and an ACU. A drum is the biggest part in the dryer where the clothes are located. There is also the baffles, these are located inside the drum. When the drum spins to dry clothes, the role of baffles are to change the motion of the clothes so that they are evenly dried. As any other electrical and automatized device, the ACU or Appliance Control Unit is a master processor which it controls the functionality of the dryer.

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Figure 1.3 Schematic of a Functional Dryer

The current sensing technology such as moisture sensor in Whirlpool’s dryer is located

next to the lint screen in front of the machine. This sensors are able to sense the

moisture in the laundry load, and the temperature sensor is located at the back of the

machine outside of the drum. The issue with this current technology is that those are

located at specific places inside the dryer. Team 10’s design objective is to increase the

number of sensors in order to have a more accurately sense of moisture and

temperature in the laundry load.

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Chapter 2. Exploring Solutions ­ Selecting a specific approach

2.1 Strategizing the goals ­ Fast Diagram

Before building a prototype, Team 10 used a Function Analysis System

Technique (FAST diagram) to help communication between team members. By using

this technique the team will have a clear understanding of the project and key functions

of the product. The FAST diagram shown in figure 2.1 explains the main function:

sense moisture inside a dryer and in the right side the steps the team will cover to

accomplished the main objective.

Team 10’s design uses moisture sensors connected to a Microcontroller

ATMEGA328. The sensors are placed inside a baffle located in the dryer’s drum. Once

the dryer is running, the sensors measured humidity and this reading will be send to the

other microcontroller working as an ACU that controls the dryer’s functionality.

Figure 2.1. ­ FAST Diagram

As it is shown in the FAST diagram, the project is divided on two main parts:

signal transmission and power generator. The first one should be a reliable wireless

application able to transfer data and read information from the sensors. The power

generation part could not be connected to AC power and be able to produce enough

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power for the signal transmission process. The design should be also be able to work

properly under hazardous conditions like high temperatures and constant movement.

2.2 Analysis by House of Quality Technique

A house of quality is a voice of customer analysis tool. In order to guarantee our

design will meet our sponsor’s expectation, the group uses this technique to understand

what Whirlpool Corporation would like to add/improve in their current product. This

process was completed by the second week of the semester and it is based on the

customer requirements. Below in figure 2.2.1, it could be seen at the top (the roof) the

design requirements for our design and how these features are correlated between

each other. The left side of the matrix expresses the sponsor’s needs. The bottom part

displays the percent of how important these requirements are for their current product.

At the end, the house of quality is a technique the group used to improve the planning

process so our customer (Whirlpool Corporation) will be satisfy with the solution the

group decided to use.

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Figure 2.2.1 ­ House of Quality for design requirements.

2.3 Power generation (Pugh Matrix)

The Pugh Matrix below (Figure 2.3.1) helped to decide the power generation

method that the team used in the design. The matrix a series of attributes ranked on

how important they are for our sponsors and compared them in different methods. As it

could be observed in figure 2.3.1, the battery solution should be the best method, but

when this solution was discussed with our sponsor, it was considered not reliable

because the battery’s life will be between 3­5 years causing the customer to replace it

eventually. The following solution was to use Faraday’s induction method to make a

induction charging unit. This solution was also not viable because the size of the

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prototype and the magnetic interference with the metallic drum. Eventually,the team

decided to use a revised­motor as a generator to power the transmission and sensor

units.

Figure 2.3.1 ­ Power Generation Method

2.4 Wireless Communication (Pugh Matrix)

Team 10 has laid out a pugh matrix with important properties to help choose a

suitable solution of the wireless communication task. Table 2.4.1 has different

technologies available in today’s market. This type of technology includes: Wi­Fi,

Bluetooth, Optical, Zigbee, and Radio Frequency. Although they all were a viable

solution to our communication requirements, the table shows how each method was

rated. The attributes were scored from 1 to 5 according to how important they were to

the sponsor. The highest ranked properties for our design were cost, durability and

availability. The reason why those were ranked as 5 is because Whirlpool corporation

established that they are looking for a device that does not cost them more than $5 per

unit but still be able to have the same life­span of the dryer (between 8­10 years). After

considered all the available options, the most suitable wireless technology for the

project was found to be Radio Frequency (RF) technology.

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Potential Concepts

(Rank 1 ­ 5)

Attributes Importance

(Rank 1 ­ 5) Wi­Fi Bluetooth Optical ZigBee Radio

Power

Consumption 4 3 3 5 4 5

Data packets 2 4 3 5 3 4

Range/distance 3 3 3 5 3 4

Frequency 2 4 5 5 5 4

Cost 5 3 1 3 4 4

Durability 5 4 3 4 5 3

Size 2 2 4 3 3 4

Simplicity 4 2 4 4 3 4

Availability 5 3 3 3 4 5

SCORE 97 96 127 124 132

Table 2.4.1 ­ Communication Pugh Matrix

2.5 Budget Planning and Price per Device

Whirlpool Corporation established that regardless of the design the team will use

to approach the problem, the total cost per device should be less or equal to $5. The

price per unit was based on how many parts a large sized company like Whirlpool

Corporation will buy in order to integrate the device in their current and future products.

As every other senior design team, Team 10 was provided with a budget of $500 .

Based on the selected type of wireless communication and power generator, the team

was initially expecting to spend $94 for the prototype. The breakdown price by parts for

the initial prototype is described in figure 2.5.1 but as any other engineer project, the

design was modified based on the testing process giving a result of new prototype cost

of $90.08 (refer to figure 2.5.2).

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Figure 2.5.1 Budget Planning ­ Initial Prototype

Team 10 ended the semester with a $87.20 left in its budget. The team spent

$185 in building a prototype and $88 in materials to support the testing process and

other expenses. Some of the auxiliary components the team bought includes:

capacitors, sensors, motors, different variations of motors among other components.

Figure 2.5.2 ­ Budget planning of Iterative design

As it was stated before, the price to put the prototype in production should not

cost more than $5. To establish a reference price of the device, the engineers from

Whirlpool co­working with the team established that a good reference could be half of

the cost of a part when the highest quantity is ordered through the website

www.digikey.com. In other words, for example if the moisture sensor HIH­5030­001 is

listed as $3.55 when 5000 units are ordered, then the price estimation for this part

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would be $1.78. The price of the design in production is $4.58. A breakdown of the price

by components is shown in figure 2.5.3 and table 2.5.3

Figure 2.5.3 ­ Estimated cost per unit of design in production

Table 2.5.3 ­ Breakdown price by components

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2.6 Timeline ­ Gantt Chart

Figure 2.6.1 Week 1 ­ 3

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Figure 2.6.2 Week 4 ­ 6

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Figure 2.6.3 Week 7 ­ 9

Figure 2.6.4 Week 10 ­ 11

Figure 2.6.5 Week 11 ­ 12

The figures above show the Gantt chart table task entries and the Timeline of the tasks scheduled.

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Chapter 3. Technical Work/Content ­ Technical Description

3.1 RF Process

3.1.1 Early Stages of MCU/RF Components

The goal of this project was to implement a humidity/temperature sensing system

into a small baffle inside the drum of a dryer while it is drying which could communicate

with a control unit outside the drum. Since the team will not program the control unit

currently implemented in the test dryer, the team was required to create a receiving

circuit as well which would be located in position similar to where the ACUt would be

located. Since Whirlpool would provide their own control unit in the final product, the

receiver costs would not be included in the final costs.

At the start of this project, the team identified the key constraints of the

microcontroller that would be used for the transmitter. First, the team would need a

MCU with an ADC and a port which could enable RF transmission, such as a Universal

Synchronous Asynchronous Receiver & Transmitter (USART) port. Since the system

would be undergoing a series of high temperature and humid conditions, proper

insulation was needed make sure it could withstand these conditions and still operate

normally. In order to meet the size specification of the system, the team wanted to keep

the MCU as small as possible while still having the necessary ports. the team was also

tasked with keeping the transmitting systems below the cost of $5 when bought in bulk

so a cheap MCU was first used to stay in our cost range.

After researching possible microcontroller units, the team first decided upon the

PIC16F688 (Figure 3.1.1) by Microchip. It is a low cost 14­pin MCU with an enhanced

USART, 2 ADC, a wide operating temperature range, and many low­power features (as

well as a sleep mode). This MCU uses In­Circuit Serial Programming (ICSP) in order to

program its functionality, so an external debugger which could work through these ports,

known as a PICkit In­Circuit Debugger had to be ordered (Figure 3.1.2).

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Figure 3.1.1 Microchip PIC16F688 Figure 3.1.2 PICkit3 In­Circuit Debugger

After working with this MCU shortly, the team found that a MCU which they had

previous experience with would be possible to implement into our design. With this new

knowledge, the team decided to switch our MCU to the MSP430G2553.

3.1.2 MSP430G2553

In the lab portion of our class, the team used an experimental PCB known as the

TI Launchpad (Figure 3.1.3) to program a Digital Color Organ. The TI Launchpad hosts

a MCU known as the MSP430G2553 (Figure 3.1.4) in order to handle all of its

functionality. In order to implement our Digital Color Organ, the team was required to

use the ADC of the MSP430G2553 to take a microphone or line­input signal and have it

modulate a bank of lights. This practice was very fundamental to what would be we

would doing in our own project. By removing the MSP430 from the TI Launchpad, we

could transfer the MCU to another PCB which we would use in our system.We

researched the MSP430G2553 and found that it was also a very low cost MCU, worked

in our temperature/voltage range, and housed a UART port. We had already

programmed a form of ADC on the MSP430 using the TI Code Composer Studio so we

could easily edit the code for our system and add the functionalities for RF transmission.

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Since we would be using the MSP430 for transmit the data, we decided it would be

better for us to use another MSP430 to receive the data as well.

Figure 3.1.3 TI Launchpad Figure 3.1.4

MSP430G2553

The MSP430 uses interrupts and interrupt service routines (ISRs). Once the

system triggers an interrupt, the system wakes up, runs the code inside the

corresponding ISR, and takes the system back to a low power state. Our sponsors

wanted a system which could last for 5 or more years, so this method would be perfect

for our system as it would reduce its power consumption over time. The transmitting pin

of the MSP430 interrupts the system whenever the transmitter is ready to transmit data.

We implemented our ADC inside the ISR for the transmitter so whenever the system is

ready to transmit, the ADC takes the current reading and sends it to the receiver. On the

receiving end, we set up a similar system except we used the receiver interrupt and

ISR. When the system was ready to receive data, the system would be interrupted and

the data received would be saved to a temporary variable. We could then monitor this

value in real time using the debugger of the TI Code Composer.

Once the programming was complete, we uploaded our code to the TI

Launchpad and tested it. Our system would properly interrupt when the transmitter was

ready to transfer and, through the use of an oscilloscope, we monitored the signal being

sent by the transmitter and verified is was transmitting a signal. The receiving also

properly interrupted the system when it was ready to receive data but it would never

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receive the data. We initially assumed there was a problem with our transmitter and

receiver. At the time, we were using a straight wire for an antenna. To optimize our

signal, we created a quarter wavelength antenna and used it in our system, to no avail.

We also researched possible mistakes we could have made with our program but could

not find any possible solutions.

At this point, it seemed that our current design would not work. Consequently, we

researched other MCUs which we could implement in our system. The Arduino Uno,

which hosts the Atmega328 in the same fashion as the TI Launchpad, seemed very

promising for our system but its cost seemed to be a possible issue. After researching

the Bare Bones Arduino project, in which Arduino PCB such as the Uno were recreated

on another PCB using no other components except those necessary for functionality,

we decided it was possible to implement into our system if we used this method as well

as the correctly priced components we need for full functionality of our system.

3.1.3 Arduino Uno/Atmega328

For our final design, we used the Arduino Uno R3 which hosts the Atmega328

microcontroller. The Atmega328 (Figure 3.1.3) is a low power MCU that hosts multiple

analog comparators which we could use to read our sensors, as well as USART ports

for our transmitter/receiver. An advantage of this MCU is that can be pulled directly from

the Arduino Uno PCB and implemented directly into our design with its most recently

uploaded program.

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Figure 3.1.5 ­ Arduino Uno Figure 3.1.6 ­ Atmega328

The Arduino family has a free IDE available for download on the Arduino website

with many tutorials for users to familiarize themselves with. This IDE can be easily

installed and used to program any Arduino PCB which can be connected to a computer.

The Arduino IDE also uses C/C++ language, which our team has extensive knowledge

in. The analog comparators of the Arduino Uno uses a 5V reference by default when

reading the current value and saves it as an 8 bit value ranging from 0­1024. This

means the output of the ADC will be follow this equation:

ADC Output = ( vOut / 5 ) * 1024

Since both of our sensors output voltages below 5V, the value returned by the

default comparison can easily be translated into its output voltage. Using this value, we

can input the output voltage into the equation provided by the sensors to find the current

RH/temperature being measured.

There are many libraries native to the Arduino microcontroller which can simplify

much of what we are trying to achieve. The VirtualWire library is an Arduino library that

provides basic functions to send/receive messages between multiple Arduinos without

addressing, retransmit, or acknowledgement using amplitude shift keying. Messages

are also sent with a cyclic redundancy check (CRC) checksum to ensure the message

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is sent correctly. Using the functions provided in the VirtualWire library, we were able to

easily implement communication between 2 Arduino Unos. We then used the serial

monitor of the Arduino IDE to monitor the value in real time and test our system. After

we ensured our system was communicating properly, we were tasked with

implementing the Atmega328 into our circuit outside of the Arduino Uno PCB.

In order to use the Atmega328 in our breadboard design, we had to make the

necessary connections first. The schematic can be seen in Figure 3.1.7. After designing

our circuit, we tested our transmitting circuit, including our transmitter and sensor

connections. The RF communication was successful, but the value we received was

incorrect. There are many ways our circuit could have been incorrectly designed, but we

did not have any further time to explore solutions to our issue. Our final design will still

utilize the Atmega328, but it will still be mounted on the Arduino Uno for the time being.

Figure 3.1.7 ­ Atmega328 Layout on Breadboard

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3.1.4 Transmitter

Every RF (radio frequency) system includes a transmitter. This component is the

one in charge of generating and amplifying a carrier wave. The process of transmission

occurs when the electric current of the power source is converted into a radio frequency

alternating current. This energy will radiate off from an antenna as radio waves until this

signal is received by another device operating in the same frequency.RF transmitters

are often used in products such as remote control, garage doors, alarm systems or

anti­theft products.

For the purpose of this project, the transmitter works under the concept of

amplitude shift keying (ASK). This type of modulation consists in representing a

sinusoid in a discrete amplitude level. As a typical digital system, the message will vary

between the binary numbers 0 and 1. In an ASK system, the binary symbol 1 is

represented by transmitting a fixed­amplitude carrier wave and fixed frequency for a bit

duration of T seconds 2. In other words, the signal will be transmitted when the value is

1 and only the amplitude will changes, the frequency and phase stay the same. As it

could be observed in figure 3.1.4.4433 there are discontinuities at transitions points and

the reason for this is to avoid a wide bandwidth if is not required. The limitation in the

bandwidth will create a modulation in the signal. It is important to mention that in the

ASK system there is a one to one relationship between bit rate and baud rate and this

system is susceptible to noise as it could be observed in Figure 3.1.4.1.

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Figure 3.1.4.1 ­ Amplitude changes in ASK method.

The transmitter used in this project is a MX­FS­03V transmitter operating at

433MHz. This model was a good selection because its relative low price and ability

cover the project’s requirements. It could resists temperatures inside the dryer that

could range from 5 to +85 Celsius and the operating frequency is under a band that

does not requires a communication license. The circuit schematic of the transmitter is

shown in Figure 3.1.4.2.

Figure 3.1.4.2 ­ Transmitter schematic circuit.

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The previous schematic will work under an operating voltage between 5 to 12

Volts, 35 mA and output power between 4 to 12 dBm. The transmission of data occurs

at a rate between 1Kpbs up to 10 Kbps. Although the range is not a main concern for

this project, this model could transmit up to 90m in open area so the signal inside the

dryer is guaranteed.

The final product has 4 pins and its description is shown in Figure 3.1.4.3. The

first pin correspond to ground. Pin 2 is the one connected to the microcontroller and it

will act as serial data input. The supply voltage (Vcc) will be in the third pin. The last and

fourth pin is optional. This is in case it is desired to improve the range of the transmitter.

Figure 3.1.4.3 ­ RF Transmitter

3.1.5 Receiver

A RF receiver is configured to pick up emitted radio waves produced by a

transmitter working at the same operating frequency. A super­regenerative receiver is

used in this project (see Figure 3.1.5.1). It consists of an amplifying transistor with its

output connected to its input through a feedback loop. This type of receiver has some

benefits like small number of components and low power consumption, this last feature

is a very important one because the team has to find a solution to power the system

without using AC power and Whirlpool disregarding the idea of implement a battery in

order to seek customer's comfort.

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Figure 3.1.5.1 ­ Receiver’s schematic circuit.

We used the MX­03V receiver in this project (refer to Figure 3.1.5.2) , which

works under a operating voltage of 5V. and working of less than 5.5mA. This receiver

uses ASK demodulation system, an operating frequency of 433 MHz, and a bandwidth

of 2 MHz. An antenna was connected to one of the pins to increase the effectiveness of

the RF communication system between devices. The final product has 4 pins. The first

one from top to bottom corresponds to GND. The second and third are pins for data and

the last one is power the transmitter.

Figure 3.1.5.2 ­ RF Receiver.

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3.1.6 Antenna

An antenna is defined as a device used to transform an RF signal into an

electromagnetic wave in free space and to transform an RF electromagnetic wave into

an electrical signal. In order to extend the range of the communication between the

sensors circuit and the ACU, Team 10 used a helical quarter wave antenna

constructed from copper. The design of the antenna it is very important because

different types provide different parameters such like gain, radiation pattern and

bandwidth.The helix antenna was the perfect team for the design because it will provide

a reasonable range but without compromising the space inside the baffle.

A helix antenna consists in a specific number of turn and specific length

according to the desired wavelength. The team used a 31.75 mm radius with 5 turns coil

shaped. The length of our antenna was calculated to be 16.4 cm and it will operate at

433MHz. Without adding this component to the circuit, the communication between

devices was found to be around 25 cm, after the antenna the communication part was

tested to be able to work up to more than 7 meters. The antenna was located as far

away possible from shielded areas, high voltages or any other component that could my

created interference with our design.

3.2 Power Generation Process

3.2.1 Faraday Flashlight

Eventually the team decided that using batteries to power the sensor module was

not practical in terms of longevity and appeal. A more sustainable way to power the

sensors had to be developed...and the initial idea was to use induction. By utilizing the

dryer drum’s rotational motion, the team was hoping to implement an induction device

inside the drum to power the sensors. This idea was derived from the concept of a

faraday flashlight. Which is a type of flashlight which is powered by kinetic motion

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(shaking). The reason these flashlights is called a Faraday flashlight is because it

utilizes faraday’s law of induction (figure 3.2.1).

Figure 3.2.1

A faraday system uses a magnet and a copper coil to induce current and voltage.

Due to the behavior of magnetic fields, when a magnet passes through the copper coil,

current is induced in the wire and can be used to power a device (ie. sensors). The

team initially developed a prototype by using a section of pvc pipe roughly 9 inches, 10

ft of copper wire wrapped densely around the pvc pipe, and one quarter sized cylindrical

neodymium magnet figure (3.1.2).

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Figure 3.1.2

By mounting such a device in the drum, the rotational motion would provide

enough kinetic energy to move the magnet within the tube back and forth, thus passing

the coils multiple times. The voltage induced from each pass would be stored in a

capacitor. Theoretically, after a few revolutions of the drum, there would be enough

energy stored in the capacitors to power up the sensors and send data to the

transmitter. Using induction as a power source extends the lifespan of the sensor

system dramatically compared to a battery. Only when the dryer is active will the

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sensors be on and drawing power, thus preventing any excessive fatigue on the

electrical components.

However the induction system did have It’s drawbacks when trying to implement

it into the dryer. First, since neodymium magnets are very strong, it will catch any

ferrous material within about 5 inches of it...including the drum. This became a major

problem as when the magnet came closest to the drum during its oscillation to the tube,

the magnet would get caught in that position, thus restricting it from freely moving

through the tube and passing through the coils. Initially the team suggested to created a

buffer to increase the distance between the drum and the magnet to minimize any

attraction between the two, however doing that made the device much more bulky and

may reduce effectiveness of tumbling clothes in the dryer. Another problem was that

since the prototype was composed of the cheapest materials the team could find,

quality of the parts were lacking, and only a small amount of voltage was induced per

pass between the magnet and coil, not enough to power the sensors. This could have

been solved by using high quality magnetic wire, and a larger and stronger magnetic

wire. Unfortunately the level of quality of those components was extremely expensive

and impractical for the team’s design budget goal. This required us to once again

rethink our strategy on how we would accomplish this task.

3.2.2 Power Generator

The group explored the option of using a motor working as a generator. For the

purpose of this project, a 12 V DC 600 rpm motor was used in order to power the

sensing device. Our decision of using this type of motor was based on the rpm of a

typical size dryer (around 4.3 cu ft). An average dryer will produce 60 rpm but this

amount will vary according to its drum’s diameter, so if the motor is connected to a

rubber wheel then the rotation across the motor will increase up to 10 times the dryer’s

rotation, in addition a gear box was installed with an appropriate gear ratio to help

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accommodate the required rpm in order for the generator to produce enough power

(figure 3.2.2.1).

figure 3.2.2.1

The overall design will required a power of 102 mW (refer to table 3.2.2). To be

able to supply enough power, the group picked a 12 V and 150 mA rated current motor.

The group feel confident about this being a good approach because its relative low cost

and the fact it is based on mechanical energy transform into electrical energy, it will

guarantee a life span between 8­10 years.

34

Table 3.2.2 ­ Total Power Consumption

The implementation process behind this power generation method is based on

the rotation of the dryer. This will produce movement at the shaft of the motor creating

the power requirements of our sensing device. A voltage regulator will be connected to

the motor that way the voltage going through the sensing circuit is constant having a

result of a smooth signal transmission.

3.2.3 Voltage Regulator/Boost Converter

A motor working as a generator is used to power our sensor circuit. The

generator is capable to produce up to 12 V and to avoid overload the circuit, the team

used a voltage regulator. The schematic of the voltage regulator used in this project is

shown in Figure 3.2.3.1. This circuit consisted in two different outputs of 5 and 3.3 V.

because the different components power requirements. The humidity sensors and

transmitter/receiver RF system will be connected to the 5V output. The microcontroller

in the other side, will be connected to the 3.3V. In the schematic it could be observed

there are other components like lossy and electrolytic capacitors that are connected in

parallel to block the high frequency noise. The circuit uses a LM2940 low dropout

regulator. This is a positive voltage regulator with an output current of 1 A and typical

input voltage range between 6V and 26 V. This regulator works to protect our design

from short circuit limit and it will step out voltage from 9V to 5.0. To step down from 5.0

35

V to 3.3 V, then a LM3940 low­dropout regulator was used. Once the circuit was fully

functional, the team decided to used in our design. The estimated cost for this voltage

regulator is $0.73. The price breakdown is shown in Table 3.2.3.1

Figure 3.2.3.1 Voltage Regulator.

Table 3.2.3.1 Estimated cost for voltage regulator.

The team considered the option that in case the generator will not produce

enough voltage to operate the circuit, then a boost converter could be used. For this

type a circuit, our team considered to used a TPS61220 linear regulator. The schematic

for this circuit is shown in Figure 3.2.3.2. At the end this option it was not used due the

36

fact the team decided to go with a motor that was able to produce up to 12 V per 1000

rpm. This boost converter will take an input voltage of 2.5 V and set it up to 3.3 V and

then to 5.0 V.

Figure 3.2.3.2 Boost Converter.

3.3 Sensor System

3.3.1 HIH­5030

The current design for Whirlpool dryers measure the humidity in the air of the

drum to estimate how dry the contents of the drum are. In order to sense the humidity

inside the drum, we had to research possible humidity sensors which we could

implement into our system. We first identified the key specifications of our sensor: the

capability to sense humidity without physically interacting with the contents, an analog

output voltage, small component size, low­cost, and low power consumption. After

narrowing our search, we decided to use Honeywell HIH­5030 Humidity Sensors.

37

Figure 3.3.1 Honeywell HIH­5030

The Honeywell HIH­5030/5031 Series Low Voltage Humidity Sensors operate

from 5V down to 2.7 Vdc, often ideal in battery­powered systems. The HIH­5030 is a

covered, condensation­resistant, integrated circuit humidity sensor that is factory­fitted

with a hydrophobic filter allowing it to be used in many condensing environments, such

as our dryer. It hosts 3 pins: VCC pin for power, a data pin (which outputs an analog

voltage), and a ground pin. With an analog output voltage, we could easily measure the

output of the sensor with our MCU using an ADC. Honeywell also provides an equation

for measuring the current RH using the output voltage.

Vout = (Vsupply)(.00636( Sensor RH ) + .1515) Provided by spreadsheet

­> Sensor RH = ( Vout / Vsupply ) ­ .1515 ) / .00636

After converting our output voltage into its proper value, we can properly use this

equation to estimate the current RH as measured by the sensor.

3.3.2 LM35DZ ­ Precision Centigrade Temperature Sensor

The current Whirlpool dryers do not use temperature sensors to estimate the

dryness of clothes inside the drum. They simply use a thermistor near their thermistor to

ensure the dryer does not exceed a certain threshold of heat for safety reasons. We felt

as though it would be useful to also know the temperature of the clothes in the drum for

38

research and testing purposes, so we decided to research possible temperature

sensors we could implement into our system. After identifying the key components

necessary for our sensor (cost, size, power, output), we decided to use the LM35DZ

(Figure 3.3.2) developed by Texas Instruments.

Figure 3.3.2 Texas Instruments LM35DZ

The LM35DZ are precision temperature sensors with an output linearly

proportional to the measured temperature, much like our humidity sensor. This could

easily be connected to our MCU and processed through an ADC converter to find the

current temperature being measured. Measuring the current temperature has its

advantages as far as research is concerned, but we did not feel as though it was

integral enough to our design to keep in our final schematic. Removing this sensor

rewarded us with less power consumption and a lower overall cost for our design, which

are 2 of our key concerns.

39

Chapter 4. Data Testings

4.1 Implementation of Devices

Once the sensors were operational and connected to the transmitter unit, it was

time to install the sensor and power system inside the dryer for final testing. The first

step in the implementation phase was to develop some sort of housing for the sensor

and power supply so that they would be immune to any heat and moisture that drier

conditions would produce. At the same time, the housing had to offer a way for the

sensors to detect temperature and humidity accurately as well as allowing radio

transmission to pass through. Initially the team wanted to fit the sensors and transmitter

inside one of the polymer baffles inside the dryer. The biggest obstacle with this idea is

that the baffles had very limited space and would be difficult fitting the bulky circuitry

inside. Next was to cut out openings on the baffles where the sensors would be

exposed to environment inside the dryer. Careful measurements had to be taken when

making the cuts to ensure that the sensors would fit tight enough so that no moisture

could leak into the housing and damage the circuit. Caulk was applied around the cut to

further insulate the circuit housing.

The generator unit was a bit more trickier to fit within the dryer because of its

orientation and size. Since the generator had a wheel that had to ride up against static

areas inside the drum placement was very limited and had to be precise. After further

examination, the best place to mount the generator unit was on the lip of the drum

housing on the front of the dryer. A mount had to be made that would give the correct

height for the wheel of the generator to make contact with the lip at all times when

spinning. The voltage regulator would also have to be hooked up with the generator so

the team found a medium sized metal box to use as the mount and housing. Generator

would be mounted outside of the box and the wires would run from the motor to the

inside of the box through a small cut to feed the voltage regulator. Once the generator

box was mounted properly, insulated wires would ran from the voltage regulator inside

the box to the sensor unit inside the baffle located directly behind it.

40

Finally The dryer was hooked up and the team ran the entire system. Once the

dryer cycle was started and the drum started spinning, the generator did infact was able

to produce power from the drum’s rotation to feed the sensor unit.

4.2 Communication Testings

In our final design, we used the Atmega328 as our MCU to control the flow of our

transmitter circuit. We initially programmed the Atmega328 using the Arduino IDE while

it was mounted on an Arduino Uno and removed it to be used in our circuit. Our receiver

was also designed using an Arduino Uno, but our sponsors were more concerned with

the transmitter. In their final production, they would be providing their own MCU with a

receiver for a control unit that would interface with the current transmitter that we were

creating.

Our transmitter/receiver program uses the VirtualWire library for access functions

which greatly simplify RF communication using Arduino PCB. The VirtualWire library is

an Arduino library that provides basic functions to send/receive messages between

multiple Arduinos. Much like UDP in networks, the VirtualWire library can send

messages without addressing, retransmit, or acknowledgement by using amplitude shift

keying. Using a checksum field, the messages are checked to ensure they have been

correctly received, although at a highly simple level.

Our transmitter code begins by initializing the ports to receive the transmitter data

as well as initializing an I/O port connected to an LED (initially connected to an LED on

the Arduino Uno) . We then begin our loop which controls our RF transmission and

ADC. First, we process the current value of our sensor output through the ADC. We

then convert the data to a character string which we can transmit properly through the

transmitter. Once this signal was sent, we modulated our LED to visually show that a

signal was sent by the circuit. This process continuously loops until the circuit eventually

loses power after the cycle has finished.

41

The receiver code follows a similar process as the transmitter. We first initialize

the receiver pin and the serial monitor, which we can use to output information to an

external window. Our main code, implemented in a loop, first reads the output of the

ADC being received by the receiver. This value is then processed through an equation

which can estimate the current RH being measured.

We initially tested the RF communication by placing the circuits next to each

other on a table. After verifying our circuits were functioning properly, we placed the

transmitting circuit inside the drum to ensure the signal could be received through the

metal of the drum. We mounted our receiver circuit in the same location as the control

unit of the dryer, which is where Whirlpool would implement their own receiver if this

were to be put into production. Our tests showed that we were properly receiving a

signal through the drum without any interference. On our trip to the Whirlpool

headquarters, located in Benton Harbor, MI, we were also able to test our transmitting

circuit inside of other dryers made up of different materials as well as a Thermotron, all

without any interference.

4.3 Sensor Testings

The team visited the Whirlpool global headquarters located in Benton Harbor, MI

on December 4th. After we updated our sponsors on our progress thus far in the

project, we received a tour of their facilities. While on our tour, we were able to test our

design in a Thermotron, which can simulate certain temperatures and humidities inside

of a machine. We placed our transmitter inside the Thermotron and tested our system

by monitoring the receiver outside of the Thermotron. The signal was successfully

received outside of the Thermotron and stayed constant with no errors.At this point,

however, our design simply took the analog output and compared it to its maximum

output of 3.3V to estimate the humidity. Our results can be seen in figure 4.3.2 and table

4.3.2.

42

Humidity (%) Prototype Output Theoretical Output

Accuracy (%)

22 192 225 85.33

23 197 236 83.47

24 198 246 80.49

25 201 256 78.52

26 206 266 77.44

27 210 276 76.06

Table 4.3.2 ­ Sensor testing results

Figure 4.3.2 ­ Prototype Sensing results.

From the results of our test, we realized that our design would increase with the

humidity but it was not compensated properly. After our trip to Whirlpool, we researched

43

our sensor and found an equation provided on the datasheet which we could use to

properly identify the current humidity.

Vout = (Vsupply)(.00636( Sensor RH ) + .1515) Provided by datasheet

­> Sensor RH = ( Vout / Vsupply ) ­ .1515 ) / .00636

After properly adjusting our programming code, it was decided to test one more

time the functionality of our circuit design . The group didn’t have the luxury of using a

Thermotron to test our system so this time a humidity sensor by Acurite Company was

placed inside the Senior Design lab to compared our outputs, the results are shown in

table 4.3.3

Humidity (%) DT10 Sensor (%) Acurite Sensor Model(5)

29 226 ­ 28.76 29%

31 238 ­ 31.55 31% Table 4.3.3 ­ Results measured inside 480 Senior Design Lab.

4.4 Power Testings

The power generation was one the most difficult task in this project. The group

tried two different power generation methods (Piezoelectric sensor transducer and

Faraday’s Induction method) before decided that for our final design, the most suitable

solution could be a motor working as a generator.

A piezoelectric vibration sensor (see Figure 4.4.1) was tested inside the dryer.

The idea was that the rotation of the dryer will create enough vibrations in order the

sensor could transduce the input and produce certain amount of power. This sensor by

Measurement Specialities could create up to +/­ 90V when it under constant flexibility,

touch or vibration. Some of the features of this film include a higher voltage output and a

great flexibility what will guarantee a life­span of 2­3 after being under constant

vibration. At the beginning this looks like a good alternative for our power generation

problem because if the dryer is OFF, then there won’t be voltage produced. In other

44

words this means,it will contribute to avoid more complex programing coding like a

switch or active/sleep mode. With this power generation method there were two main

problems : the first one was that the transducer will not produce more than 2.5 V and

the second problem correspond to the implementation part. In order to keep a constant

voltage, a beam will be required so there will be more vibration per rotation. The group

considered the idea of a simple beam that will add mass to the film and oscillate aftering

being in contact with the drum but there was not enough space to implement this idea

outside the dryer. To solve the problem of low voltage, the group considered to use a

DC­to­DC converter but this will add more components to our design and it might cause

the price per device to increase.

Figure 4.4.1 ­ Piezo Vibration Sensor

The following generation method the group decided to explore was based on

Faraday’s Induction law. The group used the example of how flashlights are able to light

a bulb. Flashlights produces a certain amount of power when a changing magnetic field

induces an electromotive force producing an electric current. Basically, a flashlight is

coil of wire and magnet moving back and forward to induces a field. This prototype

sounds reasonable because its low cost price (it was calculated to cost around $2) and

45

very easy implementation process but there was a problem, the metallic material of the

drum will create an interference of the magnet’s movement.

Once the group decided to tested this prototype inside the drum, it was found

that when the drum/prototype were in a distance around 5 inches, the magnet will get

attached to the drum. One possible solution to fix this problem was to use a less

powerful magnet (the group was using a Neodymium magnet) but then, the prototype

will not produce the desired voltage to power the sensors and microcontroller. Because

the magnet and drum interference, the group decided to disregard the Faraday's

induction method.

Because the pugh matrix for power generation method helped the group to

brainstorm different power alternatives, the third method the group decided to use was

a motor uses a generator. As the piezoelectric sensor, the generator will avoid complex

software coding because the only way data would be transmitted is when the dryer is

under constant rotation. When this idea was discussed to our sponsor, the engineers

though this could be a good and factible approach to solve the power generation task.

The first generator the group decided to use was a 9 V DC motor. This first motor is a

high speed (19000 rpm without load) and low torque. The group opted for this option

because its relative low price (a per unit price of $4.99 and production cost of $0.78)

and small size. Unfortunately, the rotation per minute required by to run the desired

power were too high versus the rotation produced by the dryer. It is important to

mentioned that the motor was tested in different location of the dryer such as the

outside of the drum or inside the drum but using the back of dryer as the rotor or

stationary part as it is shown in Figure 4.4.2. The first solution the group decided to

apply in order to increase the rotation of the shaft was to add a gear set but even with

this implementation, the rotation of the dryer was not fast enough to produce the desired

voltage (between 6 ­ 9 V).

46

Figure 4.4.2 Generator located outside the drum

The generator method was still suitable but the group considered to explore different

kind of motors before disregard this idea. For example, the next motor the group tested

was a 12 V DC motor, 1.1W and 5400 rpm. This generator also did not produce enough

power but this time it was higher voltage (around 3V were produced with this generator).

The motor was tested outside and inside the drum and a rubber wheel was used as a

gear.

After analyzed the previous results, the next approach was to use a motor with

less rpm. The issue with a motor of this feature is that in order to compensate a slower

rpm and produced the same voltage, then usually the value of the torque will be higher

(see Figure 4.4.3). For example, the group decided to try a 12V DC geared motor, rated

current of 150mA, torque of 17 kg­cm and 60 rpm. Again, this intent was not successful

because although the dryer will produce the amount of rotation required by this motor,

the force is not strong enough to produce movement at the shaft. An alternative solution

for this issue was to add a gear with a bigger diameter to overcome the torque value but

the group decided not to approach this solution because it is very important that our

47

design is as small as possible in order not create interference or add more components

to the current dryer design .

Figure 4.4.3 12 V DC Motor ­ 60 rpm high torque

At the end, it was not possible find a successful motor that could work as a

generator and produced the desired power for the moisture sensor design. The results

of the different power testing is shown table 4.4.2. The group still think this could be a

great solution for the power task but it is necessary to find a specific motor that could

work with the dryer rotation. This issue could be add as a future improvement in order to

consider our design ready to be implement as part of Whirlpool’s current technology.

Method Voltage Produced Successful design

Piezoelectric sensor ∼2.5 V Partially

Faraday’s Law ­ Flashlight ­ No

9 V ­ High Speed DC motor

∼ 2.0 ­ 2.5 V Partially

12 V ­ DC motor high torque 60 rpm

­ No

12 V ­ DC motor ­ 5400 rpm

∼0.6 ­ 1.5 V Partially

Table 4.4.2 ­ Results of Power Testing

48

4.5 Prototype Performance vs. Design Specifications

After extensive testing and troubleshooting, the prototype performance fell below

expectations. The main problem was that the generator unit was not providing sufficient

power from the drum spin to power the sensors and transmitter. The motor used was a

12V high rpm rotor which meant that the generator needed a much higher frequency in

order to reach it’s 12V potential. With the frequency of the drum, the motor was only

able to produce around 2 Volts which was quite a bit short from the required 9 Volts.

Other generator models were available, such as high torque low rpm generators, but

there was not nearly enough rotational energy nor friction between the generator wheel

and the drum to spin the high torque rotor. The generation idea is still valid in the

prototype, a new selection of generators and perhaps a more efficient method to spin

the rotor are the only changes to have to be made to meet design specifications and

performance.

On the other hand, the communication between the Transmitter and Receiver

was working flawlessly, which was a great news especially when operating inside a

spinning metal drum where interference was feared to be an issue. The sensors were

also functioning, by connecting the receiver module to a computer, a live feed of

temperature readings can be obtained, to test accuracy, the team used a blowdryer on

the sensors, and as predicted the readings shot up as well as dropped down when the

blow dryer was turned off.

49

Chapter 5. Design Issues

This project design is market­driven which is to be served to the customers in the

far end and two of the main issues that are of concern to the team and Whirlpool

themselves are as follow.

5.1 Safety Issue

The team has to design the system in accordance to safety standards that

Whirlpool has. During the process of the design in this semester, the team always has

safety concerns in minds. The team bought supplies that are first handed with perfect

conditions from reliable sources. The team thinks that the current design could be safer

in integrating the design circuit in the baffle of the drum because the sensors are

exposed to the laundry load which could be an issue when the clothes’ hanging strings

were to get caught with the sensors could result in sensor damagings. The way to

improve this issue is to create new designed baffles specifically for putting this project’s

design circuit inside and protect the sensors from outer unreliable source environment.

Another issue that is related to safety is the accuracy of the sensors. The accuracy of

the sensors could be source of safety issue since the team wants to output the data as

exact as it has to be. One of the options to improve this is to obtain a higher price which

leads to a higher quality sensor.

5.2 Cost Issue

The team has come across cost issue which is to be expected as the final

product of the design cost needs to be as low as possible to be able to compete with

other competitors. This issue has become quite a large problem to the team because it

took us a long time to find the parts and components needed for the design that fit

within the price range required. This also makes the implementation harder as well due

to the low level aspect of the design, meaning that the team has to work on some

aspects of the design that more expensive parts already have ready, resulting in more

time spent with more complexity. Cost issue becomes a trade­off between itself and

50

safety issue because some of the components are cheap because the materials and

production processes may not be as high quality as they should be.

Chapter 6. Final cost, schedule, summary and conclusions

6.1 Project Successes (includes cost, schedule)

Our project took many turns throughout the course of the semester. The majority

of our project dealt with 2 major concerns: RF communication of the transmitting system

and a power supply which could supply the transmitter over a lifespan of 5 years.

Team 10’s prototype was successfully able to measure temperature and humidity

of inside the drum and transmit the data wirelessly to the receiver module for the dryer

ACU to analyze. The entire sensor unit costs roughly $4.97 to make, and that satisfies

the five dollar budget given for the design. However to be able to transmit the data

wirelessly was one of the main design parameters requested by whirlpool. Our final

design can be seen in Figure 6.1.1

51

Figure 6.1.1: Final Schematic

Although the power generation was not ready for the design deadline, only a few

parts are needed to make it functional. The prototype (Figure 6.1.2) was still

sophisticated enough where Whirlpool will only need to dedicate minimal time and

resources to further expand the concept and have it functioning properly with the sensor

module inside the drum.

The wireless capability of the sensor system is a great advancement in

whirlpool’s dryer line. Previous models all utilized hardwire connections which interferes

with sensor placement. Since the new sensors do not need to be wired to the ACU, they

can be placed inside the drum and receive more accurate readings compared to before

where sensors were mounted outside of the drum. Ultimately the lack of wires will cut

down on costs and the self powered generator will only add to the energy efficiency of

such dryers.

The phrase “back to the drawing board” was a common occurrence during the

design timeline. Nothing was more frustrating than going back the the drawing board

after devoting so much effort in concepts that ultimately did not work. Each setback

52

drained the team of valuable time and money. As the deadline approached there was

no choice but to devote extra hours and push through one last time. In the end the team

was able reap the fruits of their labor and proudly produced a functional prototype.

Team 10 is humbled to have worked with a renowned company on a design that will

usher in the next step in dryer technology.

Figure 6.1.2 ­ Prototype inside the dryer.

53

Figure 6.1.3 ­ Final Prototype on breadboard

6.2 Final cost in product

Team 10 ended up the semester with an amount left in budget of $87.2. If it is

considered that the group started the semester with $500, it could be considered a

successful design project because we were able to meet our customer’s requirements

but still have some budget left in case the group decides to improve our current design.

The breakdown of the final cost in product of this semester’s design is shown inFigure

6.2.1 and table 6.2.1. The graph below represents the percentage the group used to

built the prototype, the cost of components to support the testing process, shipping bills

and miscellaneous. This last category includes the amount of money group spent in

order to visit our sponsor’s facilities in Benton Harbor, Michigan .

54

Figure 6.2.1 ­ Final cost: Amount the team spent on the project

Table 6.2.1 ­ Breakdown price of final cost.

55

6.3 Further Possible Improvements

There were multiple ways our team could have improved the communication of

our design to be much more efficient. We initially planned to implement more than one

transmitter into our system since there are multiple baffles inside of the drum. If we

could have produced a program which could interface multiple transmitters into a single

receiver, we could have more sources from which we could collect data about the

contents of the drum. However, this would only be cost effective if we significantly

reduced the price of our transmitter so that 3 transmitting circuits could still cost less

than $5. We could have also placed temperature sensors to measure the temperature

of the drum. We felt it was not worth the cost and power constraints for our initial

design, but could be very useful for a later design which had less concern for such

constraints

The motor could be improved as well as the current low cost motor using in the

design has very high rotations per minute causing it to produce a lot more voltage and

current needed to run the transmitter module which could cause it to not last as long as

it needs to be, so the motor needs to have lower rotations per minute.

56

Chapter 7: Appendix

7.1 Appendix 1 Technical roles, responsibilities, and work accomplished.

The design team’s members’ photograph is shown below in Figure 7.1.

Figure 7.1 From left to Right, Qi Luo, Thurakij Praditukrit, Ariadna Fernandez, William Wang, James Fashoda

Thurakij Praditukrit

Thurakij Praditukrit’s technical role is a design manager. He participated in the

microcontroller programming and testing process of the sensors. Mr. Praditukrit was

also the project manager of our team. Through the semester he organized all the

meetings/timetables, communication with our sponsor, our facilitator, and our

professors.

James Fashoda

Mr. Fashoda’s technical is in charge of the document preparation process. Mr. Fashoda

is also the leader in the programing section. He programmed/ assembled the

transmitting circuit inside the drum He did several tests on the temperature and

moisture sensor in order to make sure it was working properly.

57

Ariadna Fernandez

Ms. Fernandez’s technical role is the lab coordinator. Ms. Fernandez ordered all the

parts and equipments that were required for this project. Ms. Fernandez also is a lead

member of the power generation section. She helped the group to solve the energy task

and tested the different types of generators.

William Wang

Mr. Wang’s technical role is the presentation coordinator. Mr. Wang is a member of the

power generation section and did the housing to assemble the power generation parts.

Mr. Wang contributed to test different power generation methods. He also created the

housing for our final design.

Qi Luo

Mr. Luo’s technical role is the application software manager. Mr. Luo focused on our

team’s website. He built the schematic of our circuits. and he is a member of the power

generation group. Mr. Luo has contributed to test the different power generation

methods.

58

7.2 Appendix 2 Literature and website references

Chapter 1.

Whirlpool Corporation ­ Background information

http://www.whirlpoolcorp.com/

Chapter 2.

Hauser, John R. ­ The House of Quality

https://hbr.org/1988/05/the­house­of­quality

Chapter 3.

MSP430G2553 ­ Mixed Signal Microcontroller

http://www.ti.com/lit/ds/symlink/msp430g2553.pdf

ATmega328P ­ 8 bit Microcontroller

http://www.atmel.com/Images/doc8161.pdf

LM35 Precision Centigrade Temperature Sensor

http://www.ti.com/lit/ds/symlink/lm35.pdf

ASK ­ Amplitude Shift Keying

http://www.eng.auburn.edu/~roppeth/courses/TIMS­manuals­r5/TIMS%20Experiment%20Manuals/Student_Text/Vol­D1/D1­06.pdf

Data sheet ­ Receiver R33A

http://www.msilverman.me/wp­content/uploads/2014/01/K1037299581.pdf

59

Chapter 4.

Humidity sensor ­ HIH­5030­001

http://sensing.honeywell.com/index.php/ci_id/49692/la_id/1/document/1/re_id/0

60

Data Reference for low dropout regulator LM2940

61

62

63

Humidity Sensor used as reference for our design.

64

7.3 Appendix 3 Program Codes, Flowchart of the Codes

7.3.1 Transmitter Flowchart

65

7.3.2 Transmitter Code

#include <VirtualWire.h>

char *controller;

char charBuf[50];

int value = 0;

void setup()

pinMode(13,OUTPUT); // Set pin 13 as output for LED

vw_set_ptt_inverted(true); //

vw_set_tx_pin(12); // Set transmitter on pin 12

vw_setup(4000);// speed of data transfer Kbps

void loop()

value = analogRead(1); // Current ADC output saved to value

String svalue = String(value); // Convert output to string

svalue.toCharArray(charBuf, 50); // Convert string to char array

send(charBuf); // Transmit output

digitalWrite(13,1); // Turn on LED

delay(2000); // Delay the system

// The same process is repeated to modulate LED

value = analogRead(1);

svalue = String(value);

svalue.toCharArray(charBuf, 50);

66

send(charBuf);

digitalWrite(13,0);

delay(2000);

void send(char *message)

vw_send((uint8_t *)message, strlen(message));

vw_wait_tx();

7.3.3 Receiver Flowchart

67

7.3.4 Receiver Code

#include <VirtualWire.h>

byte message[VW_MAX_MESSAGE_LEN];

byte messageLength = VW_MAX_MESSAGE_LEN;

long val;

long endVal;

float vOut;

float RH;

String line;

void setup()

Serial.begin(9600); // Set serial monintor at 9600 bits/sec

Serial.println("Device is ready"); // Show the device is ready

// Initialize Receiver

vw_set_ptt_inverted(true);

vw_set_rx_pin(12); // Set receiver on pin 12

vw_setup(4000); // Bits per sec

vw_rx_start(); // Start receiver

void loop()

if(vw_get_message(message, &messageLength)) // Retrieve message

line = "";

val = 0;

Serial.print("Received: ");

68

for(int i = 0; i < messageLength; i++)

val = (int)message[i] ­ '0'; // Save char as integer

line += String(val); // Append int to string

endVal = line.toInt(); // Convert message to int

vOut = (float(endVal) / 1024) * 5; // Compute vOut from datasheet equation

RH = ((vOut/3.3) ­ .1515) / .00636; // Compute RH using vOut

// Output Calculated RH

Serial.print(" Humidity: ");

Serial.print(RH);

Serial.print("%");

Serial.println();