EDSGN 100 AT&T IoT Final Design Report

­Smart Pressure Sensitive Mat­

Introduction to Engineering Design

EDSGN 100 Section 008

Team 5 Connor Mustee ­ cfm5127 Zach Cornell ­ zdc5018 Ross Lynam ­ ril5120

Nicholas Dudenas ­ nrd5134 Submitted to : Dr. College

Date: 4/16/2014

Executive Summary To make it easier for owners to replenish goods and access information about said goods from any location using the Internet of Things. In this case, a pressure sensitive mat, used in tandem with RFID tags, is used to inform the owner of the goods about the products current state. The state of the object referring to how much of the product remains, where the product is, and what the product is.The mat uses wifi to relay data to a computer that analyzes and communicates the interpreted information to the customer.

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TABLE OF CONTENTS Introduction 3

Design Requirements 3 Schedule of Project 3

Project Background 4 Customer Needs 5 Technical Research 6

Project Objectives 6 Specifications 7

Detailed Concept Development 7 Pressure Sensor 7 RFID Tags 8 RFID Sensor 9 Mat Materials 10 Connectivity 10

Conclusions 12 References 13

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Introduction The human population is becoming more and more dependent on the internet as

time goes on. Advancements are being made every day. In the world of the internet today, the next big thing is the internet of things (IoT). The IoT is basically an extreme application of the internet; it is the idea that all things can present information about themselves on the internet and share that information with one another automatically. AT&T, being a company that has lead the wireless communication industry, has established themselves as a primary company of interest in this new application of the internet. The IoT can be separated into three categories; wearables, vehicles, and home. Wearables can be connected to the IoT and accomplish tasks like monitoring the body and such. Vehicle applications monitor things in the vehicle and around the vehicle. Finally, home applications are systems that can be installed in a house that make life simpler and aid to the advancement of the IoT. Ideally AT&T would want, all these categories are to be connected automatically and interact with each other without the need of human input. These systems should be easy to use by the average person and make life easier. Our team decided to focus on the application of the IoT in the home designing a smart mat that would be placed in a fridge that would inform owners of the groceries on the products status.

Design Requirements In order to sift through our different conceptual designs, a list of requirements for all

of the designs was created. The most important aspect of of any of our designs is the ability for the mat to communicate information about what is on it to those who need to know. It was also deemed important that the designs made people's lives easier, and be more convenient than having to constantly check on the status of one’s groceries. Our design also had to take up as little space as it could to avoid taking up space from produce. Finally, it was determined that the mat ,its power source and its sensors would have to withstand temperatures ranging from 30 to 40 degrees Fahrenheit. The four requirements above where used to govern our concept selection.

Schedule of Project We first received the project on the nineteenth of March and had about six weeks to

complete it. We began by defining the opportunity and producing a reliable mission statement. Time was also spent on defining and researching the Internet of Things in order

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to ensure that our project ideas would meet the requirements AT&T set forth. Afterwards we chose the home category and proceeded to research different systems that would be intricate to the functioning of our mat. Then, we came up with specifications for our different ideas which were applied to brainstorm concepts for the mat. That step was followed by an evaluation on the ideas that resulted in choosing the final design which was then analyzed and improved after further research and development. Finally we used design software to prototype the mat and then communicated our design in a presentation.

Figure 1: Displays design process and time spent on each step

Project Background The pressure sensitive mat is a mat that is specifically used for implementation in a

refrigerator. The purpose of this mat is to identify purchased goods through RFID tags as well as determine a beginning weight as a baseline. This product then monitors each good that is placed on the mat through the internet of things. The product user can see information about what goods are in his or her refrigerator as well as how much remains of each good. Information about the maintenance of the device will also be available through internet capable devices. This information will be on the internet of things and therefore, the owner of this product will be able to access this information from anywhere at anytime.

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Customer Needs To further develop our idea of the pressure sensitive mat, we created a survey that

was given out to willing individuals between the age of 20 and 50. The age range was chosen because that age group would most likely own their own home or apartment, and find the IoT useful.We found 26 willing participants that fell in this age range to provide some feedback. The survey that we developed can be seen the the figure. Since this

product uses the Internet of Things, its application was vital to determining customer needs. The IoT is defined as a network of “things” that can be individually and uniquely identified and can share information as well as interact with other “things”. The goal of the IoT is to allow people to easily access

information about any object no matter where it is. When the IoT is applied to anything it should in­turn make things easier for people so it was determined

that the major customer need was that this product would make the customers life more simplistic. In order to determine our customer needs we used the results of our survey. These results were used to rank aspects of new technology to see what customers, who were interested in new technology involving the IoT, wanted in a product using the IoT. The results were quantified by adding up the choices for each aspect and comparing them to the total amount possible, 104. These results can be seen in the figure. The data showed that fewer people found “Energy Efficiency” and “Works with Cell Phone” important, therefore we removed them as possible customer needs but retained the rest.

Figure 2: Graph of the resulting totals of our Interest Survey

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Technical Research While this idea is new and innovative much of the technology has been used for other applications for quite some time. Pressure sensitive mats that record data in a manner precise enough for our purposes are often used in medical devices. For example, the pads that are used to show images of the varying pressures on different areas of the feet are commonplace in shoe stores. Some of these pads come with built in wifi technology

so that the data can be uploaded quickly and seamlessly to a computer. The mat would record the weight and location of objects in the refrigerator at any given time. To identify the specific products RFID ,or

radio­frequency identification, tags would need to be on all of the goods that would go on the mat ,and an RFID sensor would need to be present. RFID tags are already used for many products being sold by large corporations such as Walmart. These RFID chips contain additional data that would make it possible to know when it is time to take a trip to the grocery store and what is needed. A new and unique computer program would need to be created to analyze the data and communicate the information to the consumer.

Project Objectives By way of interpreting the results we obtained

from our survey, and combining them with the research we performed on background technology we were able to determine a list of specifications that guides us in our design. For instance, we took the interviewees want of durability to mean that it can withstand refrigerator temperatures and food and liquid spills. In addition, we understood the safe aspect to translate to user friendly and sanitary. The rest of our interpretations are listed in the following Specifications category. .

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Specifications The specs were determined by satisfying the customer needs found in the survey.

spatially appropriate requirement the mat must be no greater than 0.5 inches thick and must come in varying sizes to accommodate different refrigerator sizes and layouts.

The pressure mat must also be able to withstand liquid and foods spills as well as the temperatures that refrigerators are operated at, this accounts for durability.

The system must be able to convert the raw data obtained from the mat and RFID sensor into easily understood notifications.

Connection to the Internet of Things as specified by AT&T. This requires sensors that allow the mat to communicate over the IoT to the product user.

Cheap enough to have a large pool of consumers; in other words, cost efficient. The system, out of the box, should require little or no assembly to fulfill the customers

inclination for easy installation. All components must be sanitary and pass regulations to be in contact with

consumer goods.

Detailed Concept Development

Pressure Sensor When we were determining the type of sensors that would be placed in the core of

the mat that would send information about an object's weight to the processor that would utilize this information we considered three different types, Torque, Force and Pressure sensors. Torque sensors sense the weight of an

Figure 3: Displays matrix of pros and cons of each sensor and the reason XYZ PAD was chosen

object pressing on it by using the value of the torque applied on a lever within the sensor and then using that information, from strain gauges attached to the lever, to calculate how

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much the object that is on the system weighs.the Specific torque sensor we found the most effective was the IP68 Underwater DAQ Sensors Theta with 20lb. This sensor could process the weights of produce from 0 lbs to 20 lbs to an accuracy of one one­hundredth of an ounce. It was also waterproof which would protect it from spills. The downfall with these sensors are bothe their size and their cost. They were round which made it hard to fit the sensors close together. They are about and inch and a half tall and cost about 28 dollars per sensor which is impractical since multiple sensors are required to make up the surface are of the mat. The pressure sensor we looked at was a Tekscan model 5051. It could process psi values between 0 and 20 pounds. It is .004 inches thick ( about .1 mm) and is flexible which allows the mat to be thin and capable of flexing so the mat can be placed or removed easily. This sensor is covered in a waterproof plastic that can flex along with the sensor. The sensors can be made to withstand extreme temperatures for prolonged periods of time and cost about 14 dollars per sensor. The third sensor we looked at is a Force sensor pad. The specific Pad we looked at was a SensiTronics XYZ pad. This pad can register the weights of objects between 0 and 30 lbs. It is called the XYZ pad because it processes three different aspects of the items placed on it, their location on the pad in both the x and y directions and a Z variable which is the weight of the object.This pad is water resistant and flexible.

We chose the XYZ pad because it already had the ability to provide information about where the object is on the pad rather than just display how much and object weighed. It also turned out that this sensor cost less per square foot than any of the others.

RFID Tags Through our research we found that there were two different RFID tags that could

potentially be implemented into our system. The first of which are called active RFID tags. The active tag has an internal battery that allows the tag to constantly transmit a signal. Active tags cost generally, $15 to $100 and have a larger range that can exceed 100 meters. Active tags can accurately track the real­time location of assets or in high speed environments such as tolling. The other type of tag is a passive RFID tag. The main difference between to the two is that passive tags do not have an internal power source. Because of this passive tags have the ability to smaller than active tags. Passive tags can be as thin a piece of paper and have an area of less than one square inch. Passive tags rely on the sensor to send an interrogator signal to the tags in order for it to be activated. Once it is activated it sends a response signal back to the sensor with the pertinent

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information. Passive RFID tags have a smaller range of up to three meters and cost between $0.15 and $5.00.

Selection Criteria Passive Tags Active Tags

Low Cost + ­

Small in Size + ­

Ample Range + +

Battery not Needed + ­

Signal Strength required ­ +

Reader Cost ­ 0

Plus 4 2

Same 0 0

Minus 2 3

Net 2 ­1

Rank 1 2

Continue? yes no

Figure 4: Matrix compares passive and active RFID tags using criteria relevant to our project

After extensive research we have found that passive RFID tags would be best suited for our application. They are considerably cheaper and the precision of active tags would not be needed. Also, the a range of three meters would be more than enough to connect with all of the items in the refrigerator.

RFID Sensor There are three different RFID frequencies that the sensor can be programmed to

register. The first of these is the low frequency, which ranges from 30 ­ 300 KHz. The advantages for this setting is that there will be little radio wave interference. On the down side, it means that it is not as responsive and readings will be received more slowly. In addition to also having the shortest range of the three options, these tags are seen as unreliable for universal usage because there are slight differences in frequency and power levels in the world. The second option is high frequency, between 3­30 MHz. At this range of frequencies, the system is much more responsive to the readings but at the cost of a moderate chance of interference from radio waves. High frequency is the frequency that is commonly used for data exchange between devices. Lastly there is the ultrahigh frequencies from 300MHz to 3GHz. This option has the largest range and the quickest

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response time and the largest variety of applications. However, the ultrahigh frequencies are the most susceptible to interference.

Figure 5. Compares RFID tags of low, high, and ultrahigh frequency

The option that was chosen for the mat design was to use a high frequency setting. It is more reliable than the low frequency without having the high chance of interference that is present with the ultrahigh frequency. Not only that, but the range of the high frequency is enough to satisfy the needs without over extending on this aspect of the design.

Mat Materials The mat needs to be able to withstand both the cold temperatures of the refrigerator

and resist the potential spills. In addition to that, the mat needs to be food safe for any food that is placed on it that is not in an container. To be able to withstand the cold temperature, an insulating layer will be applied to the outside of the force resistance sensors. This will allow the sensors inside the mat to continue working in the colder environment of the refrigerator. To then protect the sensors form any potential damage that may be a result of spills or impacts on the mat, a food safe rubber will encase the entirety of the mat. This rubber will be a FDA Neoprene Rubber sheet that has been approved for repeated exposure to foods. The addition of the rubber not only makes the mat food safe but also increases the durability by prevent leaks from damaging the sensors and wiring of the mat, in addition to provided a cushion that would prevent the sensors from breaking.

Connectivity When discussing the connectivity of our device to the IoT, a lot of options surfaced

with a little research. However, we decided that the only viable options would be bluetooth or Wifi. Bluetooth is an up and coming connectivity option in the world today. In the growing

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IoT, there is newer version of bluetooth called Bluetooth Smart. This technology is used in a lot of devices on the IoT; however, it is mainly used for close range communication such as a wearable to a smartphone app. Although this technology is beginning to branch out to long range; Wifi provides some dominating attributes that Bluetooth Smart does not. Wifi is taking over in the world today, there are wifi networks available in almost every city around the United States. Wifi networks are easy to setup and inexpensive. Currently about 61% of US households have a Wifi network. This statistic is said to grow exponentially in the next five years in the US and around the world. So with Wifi being an ever growing source of connectivity around the world it only makes sense that it would have a large impact on the internet of things. With regards to our specific device, Wifi is the best choice for this reason and that it needs to be able to update as fast as possible. Wifi is also better in this aspect because in offers the ability to be password protected. This allows the owner of our product to decide how many devices can be on the network and therefore the speed of the network. Overall, Wifi is the connectivity option of choice for our Pressure Sensitive Smart Mat.

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Conclusions In conclusion, the RFID tags that we will implement on the food products that will be kept

in the fridge will be passive high frequency tags. The sensor that will be in the fridge under one of the shelves will be an active reader that reads the RFID tags that are on each food product. The Pad that all this food will be placed on is an XYZ PAD that contains force resistors that measure the resistive force through changing currents within the resistor sensors. This pad will be coated in FDA neoprene rubber which is completely food safe and will withstand food spills and such within the fridge.

Figure 8: Shows the systems diagram

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References http://techcrunch.com http://computer.howstuffworks.com http://www.tekscan.com/flexible­force­sensors http://news.thomasnet.com/fullstory/Force­Torque­Sensor­can­be­used­in­fresh­wat

er­environment­805526 http://sensitronics.com/products.php http://www.bluetooth.com http://atlasrfid.com/auto­id­education/active­vs­passive­rfid/ http://www.inlogic.com/rfid/passive_vs_active.aspx http://www.rfidshop.net/Supply­1251342khzlf­tags_c30 http://www.atlasrfidstore.com/tags_RFID_chips_s/14.htm http://www.rfidshop.net/Supply­860960mhzuhf­tags_c31/All­1 http://www.customgasketmfg.com/Products/FoodGradeGaskets

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