RETAIL SMART HANGER

By

Chung, Won Ho

Kim, Min Kyun

Final Report for ECE 445, Senior Design, Spring 2016

TA: Henry Duwe

4 May 2016

Project Number 44

Abstract

This report outlines steps taken to develop the Retail Smart Hanger, which store owners can control remotely through an intuitive user interface. Additionally, this device is able to operate both on and off the hanger to retain its portability. Hardware, software, and front end application implementation will be discussed along with design verification, followed by cost analysis and future improvements.

ii

Contents

1. Introduction .............................................................................................................................................. 1

1.1 Statement of Purpose ......................................................................................................................... 1

1.2 Objective ............................................................................................................................................. 1

1.2.1. Goals and Functions .................................................................................................................... 1

1.2.2. Benefits and Features ................................................................................................................. 1

2 Design ......................................................................................................................................................... 2

2.1 Block Diagrams .................................................................................................................................... 2

2.1.1 High Level Block Diagram ............................................................................................................. 2

2.1.2. Physical Block Diagram ............................................................................................................... 3

2.2. Block Description ............................................................................................................................... 4

2.2.1 Charging Station (Power Adapter) ............................................................................................... 4

2.2.2 Power Circuitry ............................................................................................................................. 5

2.2.3 Data Collection / Processing ........................................................................................................ 5

2.2.4 User Interface (Customer) ........................................................................................................... 6

2.2.5 User Interface (Store Employee) .................................................................................................. 7

3. Design Verification .................................................................................................................................... 8

3.1 ESP8266 – ESP01 (Wi-Fi Module) ........................................................................................................ 8

3.1.1 Wi-Fi Distance .............................................................................................................................. 8

3.2 ATMega328P-PU (Microcontroller) .................................................................................................. 10

3.2.1 Bootloader ................................................................................................................................. 10

3.2.2 Data Processing .......................................................................................................................... 10

3.2.3 EEPROM ..................................................................................................................................... 10

3.3 SPI TFT 2.8INCH LCD (Display) ........................................................................................................... 11

3.4 Power Adapter .................................................................................................................................. 12

3.5 Lithium Polymer Battery ................................................................................................................... 13

3.6 Power Circuit ..................................................................................................................................... 13

3.7 LabVIEW Front End Application ........................................................................................................ 15

3.8 ADXL335 (Accelerometer) ................................................................................................................. 15

3.9 Like Button ........................................................................................................................................ 16

iii

4. Costs ........................................................................................................................................................ 17

4.1 Parts .................................................................................................................................................. 17

4.2 Labor ................................................................................................................................................. 18

4.3 Grand Total ....................................................................................................................................... 18

5. Conclusion ............................................................................................................................................... 19

5.1 Accomplishments .............................................................................................................................. 19

5.2 Uncertainties ..................................................................................................................................... 19

5.3 Ethical considerations ....................................................................................................................... 19

5.4 Future work ....................................................................................................................................... 19

References .................................................................................................................................................. 20

Appendix A .................................................................................................................................................. 21

iv

1. Introduction

1.1 Statement of Purpose In today’s world, fashion trends are progressing at an incredibly fast pace. Frequent changes in fashion trends, along with seasonal sales force clothing retail stores to update new clothing information manually. This inefficient method decreases employee productivity, which in turn decreases profit margin due to couple of reasons. First issue is that the employees are too busy with manual tasks and are not able to interact with the customers. Another reason for a decrease in profit is due to over hiring more employees than necessary to change all of the price tags and maintain updated inventory list. Furthermore, tag information is often displayed incorrectly, which cause confusion and frustration. With that in mind, our project focuses on creating a complete intelligent and intuitive hanger system that accurately display product information to the customers with "a click of a button". Additionally, the Smart Hanger is capable of updating all of the product information remotely by following few simple instructions on the front-end application. Lastly, the hanger is capable of tracking consumer interests through the “Like Button”. Hence, all of the said features increase employee productivity, revenue, and customer satisfaction. For future work, the possibilities are endless. For example, this digital price tag with consumer interest tracking feature could become the next big method consumers buy products in any given retail stores.

1.2 Objective

1.2.1. Goals and Functions • Wirelessly transmit/receive data between smart hangers and computer

• Provide accurate product information to consumers with ease

• Generate popularity statistics through ‘Like’ button

• Power saving mode using the accelerometer

• Increase employee productivity

1.2.2. Benefits and Features • Display banner, retail/sale prices, size, and like information on hanger

• Display information the employee wishes to put onto the hanger with ease through intuitive

interface

• Provides visual trending graph via ‘Like’ button

• Smart Mechanical Design to provide ease of charging the hanger

• Rechargeable battery for portability

• Reduces amount of paper disposal through paperless system

• Standby mode for reducing current consumption

1

2 Design

Figure 1. Retail Smart Hanger System

2.1 Block Diagrams

2.1.1 High Level Block Diagram Figure 2 below illustrates the high level system overview. First, the charging station is mounted on the hanging rack, which provides DC voltage to the hangers for ease of charging with our smart mechanical design. The power circuitry provides correct output voltage to its respective components inside our PCB. Lastly, the Wi-Fi module connects to the wireless network. The front end application is also connected to the wireless network in which string packets are sent and received from the employee user interface.

Figure 2. High Level Block Diagram

2

2.1.2. Physical Block Diagram Figure 3 below portrays detailed block diagram illustrating the connections and components between each subsystem. Power supply system is composed of a DC to AC power adapter converting 120V AC to 5V DC which provides constant 5V power supply to the Printed Circuit Board (PCB) through DC male/female power plug. Then, the charge management controller is responsible for managing the battery charging through its constant voltage and current algorithm, which is a crucial component in our design in terms of portability. Furthermore, we designed the power supply to include the buck-boost converter as a mean to manage fixed output voltage of 3.3V [4] that provides power to the rest of the components, such as the microcontroller, LCD display, accelerometer and Wi-Fi module. It is important to note that instead of using different wireless protocols than Wi-Fi, such as Bluetooth to transmit/receive data between the computer and the hanger, we used TCP/IP protocol due to its cost efficiency and wide range of connectivity. In a way, our project is an IOT project that may allow incorporation of IOT wireless protocols in the near future, such as 6LowPAN or Thread.

It is important to note here that the hanger hook is detachable from our hanger. This allows the store owners to use our device as a price tag display on anywhere, making our device highly versatile. To enable this portable feature, you simply need to unhook the port connection on the PCB connecting the female DC port on the hook to the VCC and GND pin on the PCB.

Figure 3. Detailed Physical Block Diagram

3

2.2. Block Description

2.2.1 Charging Station (Power Adapter) Retail Smart Hanger features a unique charging station design. We have implemented a smart mechanical design in our charging system in order to increase its ease of use and optimize the charging efficiency. As shown on the Figure 4 below, only one wall adapter per clothing rack will be required instead of having one charging block for each hangers. Depending on the number of hangers you need per rack, the wall adapter is customizable by increasing the number of DC male/female power plugs to match the number of hangers and by taking into consideration the current rating of the AC to DC power supply.

Secondly, we have used a clip to be customizable for different clothing rack sizes in various retail stores. Instead of having to purchase a whole clothing rack to utilize this intelligent hanger, our product features a unique clamp as shown below to increase its adaptability. With correct diameter information of the clothing rack pole, clips are highly customizable to match the store owner’s needs. Furthermore, instead of having to take all the hangers off the rack every day to charge the battery overnight, we implemented a “Hang and Charge” feature, which allows the hanger to charge on the clothing rack with minimal effort, as shown on the Figure 5 below.

Figure 4. Customizable 5V Wall Adapter Figure 5. Smart Mechanical Design of Charging Station

4

2.2.2 Power Circuitry The data collecting/processing components receives 3.3V input voltage from either 3.7V battery or the 5V wall adapter. As the nature of our project requires portability, the power circuitry must have high efficiency while maintaining minimal size/weight. With this in mind, we have hand-picked our component with great care to ensure efficiency, operability, and modest physical size.

First off, the charge management controller (MCP73831) served its purpose to efficiently control the battery charging rate. With its constant voltage/current charging algorithm, the charge management controller allows lithium polymer battery to operate at normal conditions and ensure longevity. MCP73831 has output voltage range of 3.0 – 4.2V depending on the battery voltage. Therefore, our device required a buck/boost converter (TPS63001) instead of a linear voltage regulator to produce a fixed output voltage of 3.3V (see Figure 6 presented below). Additionally, we have chosen TPS63001 specifically for to ensure steady operability of being able to supply output current up to 800mA, which was crucial to our design with the use of ESP8266 Wi-Fi modules.

Figure 6. Actual Power Circuitry on PCB

2.2.3 Data Collection / Processing Data collection/processing subsystem is composed of microcontroller (ATMega328P-PU), Wi-Fi module (ESP8266), and the accelerometer (ADXL335). Instead of using off the shelf Arduino UNO or MEGA board as our main controller, we have designed our computing system to be a stand-alone IC chip (see Figure 7 below) to lower power consumption, reduce physical size of prototype, and increase the battery life.

Our initial design consisted of ATMega328P-PU operating at 5V and 16MHz external crystal oscillator with the addition of separate boost converter IC chip to step up the voltage from battery voltage of 3.7V

5

to 5V. With further research and designing our system, we found that this methodology only increased the cost in our design and made our system inefficient. Furthermore, we saw that speed of our clock was not too essential compared to our requirement to make the device low cost and efficient. Hence, next iteration of design has implemented changes to input voltage of 3.3V. Input voltage of 3.3V and oscillating frequency of 8MHz provides a more efficient way of processing concatenated string sent from LabVIEW, since the speed of update on the LCD screen is not critical component in our design.

Figure 7. Microcontroller Schematic

2.2.4 User Interface (Customer) Providing accurate and useful product information to the customers was a crucial part of our

project. This device needed to display the price with 100% consistency whenever the customer interacts with it. Figure 8 below depicts the image of our hanger. Information about the item such as a banner, retail/sale prices, size and number of ‘likes’ are shown on the display. Furthermore, product information such as brand name, clothing material, etc. is also be customizable depending on the store employee’s preference.

Another enticing feature that the Retail Smart Hanger presents is the real-time product popularity statistics through our implementation of the ‘Like’ button as shown on the left of LCD in Figure 8. Through this unique feature, shoppers have access to the data of what other consumers are interested in through the ‘Like’ values shown on display. This encourages the customers to buy the product with confidence.

Furthermore, an ON/OFF switch on the right side of our hanger provides an option of turning off the device. In case of the customer accidently turns off the device, all the product information is stored

6

in EEPROM so that it can be restored once the device is turned back on, a neat feature to our design which will be described shortly after.

Figure 8. User (Customer) Interface Figure 9. Trend Graph User (Employee) Interface

2.2.5 User Interface (Store Employee) The front end application that store managers/employees use to control the hanger is programmed through LabVIEW, a graphical programming language used primarily to easily integrate hardware solutions. In order for our hangers to be robust and useful in real world applications, we needed to devise a couple of features that would be included in the front end application.

First function serves to update hangers individually. This feature is characterized by red colored tab on the left side of user (employee) interface as shown on Figure 10. This particular feature is useful when there are many different product, each with different set of information required to be displayed on the LCD screen.

Second function allows update of all the hanger retail price to change its sale price with a click of a button. This is characterized by the green colored tab and is very useful when the store is on seasonal sales, like Christmas and New Year’s, for whole item sales. Having this feature on user (employee) interface will significantly increase employee productivity and reduce labor cost, especially on frequent sale seasons.

Third function is to update certain range of multiple hangers. This feature is characterized by the blue colored tab and this provides more flexibility in updating multiple hangers. When shop managers/employees wish to update certain range of multiple products, the employee can simply select

7

the range of the Smart Hangers and press send. As a result, only the specified hangers will be updated with the corresponding information.

Moreover, store owners/mangers can make smart investment decisions by referring to the trend graph generated from ‘Like’ values sent from the Smart Hangers (see Figure 9). Once, the shop employee clicks ‘Update’ button within the Retail Smart Hanger software program, it will automatically generate the graph based on the real-time popularity statistics.

Figure 10. User (Store Employee) Interface

3. Design Verification Requirement, verification, and result of verification of each component in our design is shown in Appendix [A].

3.1 ESP8266 – ESP01 (Wi-Fi Module)

3.1.1 Wi-Fi Distance To verify Wi-Fi module’s stable transmission and reception of string packet with varied distance away from the access point, we needed to perform systematic experimentation to check the device’s operation range. The wireless router used for testing was a Netgear Nighthawk AC1900 and we used a measuring tape to ensure precision of our data.

Table below shows the ESP8266 being able to connect up to 40m on the same floor, which surpasses our initial requirement of 20m operation range, please see Appendix A. As we performed more tests on the

8

2nd and 3rd floor, it was evident that our Wi-Fi module was not able to connect over a long distance to the access point set up by the wireless router. Figure 11 below illustrates the experiment performed with red dots indicating point of secure connection.

Table 1 Connectivity Verification Chart

Floor Level (axis of origin)

Lateral Distance [m] Data Transmission

1st 1 1st 10 1st 20 1st 40 2nd 1 2nd 10 2nd 20 2nd 40 3rd 1 3rd 10 3rd 20 3rd 40

*Note that each floor distance is laterally relative to its origin (router) through z-axis.

Figure 11 Distance of Hanger Relative to Origin

From this verification, we realized couple of good points for future reference. First, if the clothing shop is inside a multi-story building, it is best to install a Wi-Fi range extender on each floor to ensure connectivity of all the hangers. Second, this distance will vary depending on the model of your router. With future implementation of the device, buyers of this system are advised to use a wireless router with long-range specification.

9

3.2 ATMega328P-PU (Microcontroller)

3.2.1 Bootloader Since we needed to operate the microcontroller at 3.3V with 8MHz crystal oscillator, it was necessary to upload the same bootloader program as that of the Arduino Pro Mini 3.3V. We loaded firmware onto our microcontroller as outlined in Instructables [1]. After much trial and error, we were able to load firmware onto microcontroller successfully, which shows up as “Done burning bootloader” on the Arduino IDE.

3.2.2 Data Processing After data is received from LabVIEW, as shown in figures 12, it is sent to the ESP8266, and ultimately to the microcontroller through software serial. Then, we required the microcontroller to parse the data into its respective variable. As shown in figures 13, single long string sent by the front-end application is concatenated into a global string variable until a string separator is detected. This is an efficient methodology of receiving 1 long string of data instead of making multiple connections to send over each values, which would consume more power and take more time.

Figure 12 Microcontroller String Processing Figure 13 Concatenated String Sent from LabVIEW

3.2.3 EEPROM Lastly, it was crucial component of our design to be able to retain values sent over from the front end application even after it loses power. To implement this feature, we used EEPROM memory available on the ATMega328P-PU. The microcontroller supports EEPROM storage up to 1024 bytes, which was more than plenty of space for our application since each character takes up 1 byte. For the purpose of the

10

demo, we were only transmitting anywhere from 50 bytes to 80 bytes. The leftover space on EEPROM will be useful in future applications in which the hangers would be connected to the webpage of the retail clothing store for more features.

As shown in Figures 14 and 15, the implementation of writing to and reading from EEPROM is straightforward. As for writing, we need to first get the length of straight and store it for later when we read the values. Then, we create a for loop to write to address from current empty address to the size of string. As for reading the written value, you use an EEPROM.read function to first get the string size of the written value and read off the EEPROM values until it has reached the size of string as indicated.

To verify the functionality, we repeatedly turned on and off the device with different speeds to see if any data was lost with power disconnection. We saw that no data was lost with any given number of switching the power on and off as long as the user did not turn off the power while data transmission was taking place. The instance of the device being turned off at the same time store owner/manager sends the string packet is a rare event, which we have not taken into account.

Figure 14 Writing to EEPROM Figure 15 Reading from EEPROM

3.3 SPI TFT 2.8INCH LCD (Display) As with the LCD display, we needed it to communicate through SPI protocol and generate text with particular font. This was achieved by uploading the LCD library to the microcontroller. First initial verification of LCD screen was done by using example sketch of graphic test provided by Adafruit. After confirming its operation, we went on to test the font, color, cursor position, and responsiveness of LED backlight during transition from standby mode to active mode. We wanted to ensure that when the user was not using the device, it would put components that are not required for operation to sleep and only

11

have necessary components on. When the device was in standby mode, it was critical for the LCD display to turn off, as it saves a lot of power. As shown in figures 16 and 17, we see that current consumption of standby mode is about a quarter of active mode current consumption (43.48mA). During active mode, current consumption was at 153.5mA. It is important to note that standby mode turns the LCD display off and puts ESP8266 into a deep sleep mode. By verifying accelerometer’s operation through testing, we also satisfied the display’s requirement of turning off when user was not using the device.

As with the LCD display, we needed it to communicate through SPI protocol and generate text with particular font. This was achieved by uploading the LCD library to the microcontroller. First initial verification of LCD screen was done by using example sketch of graphic test provided by Adafruit. After confirming its operation, we went on to test the font, color, cursor position, and responsiveness of LED backlight during transition from standby mode to active mode. We wanted to ensure that when the user was not using the device, the device would put components that are not required for operation to sleep and only have necessary components on, such as the microcontroller and the accelerometer. When the device was in standby mode, turning off the LCD off was critical as it saves a lot of power. As shown in Figures 16 and 17, we see that current consumption of standby mode (43.48mA) is about a quarter of active mode current consumption (153.5mA). It is important to note that standby mode consists of LCD turning off and ESP8266 going into deep sleep mode. By verifying accelerometer’s operation, we also satisfied the display’s requirement of turning off when user is not using the device.

Figure 16 Standby Mode Load Current Figure 17 Active Mode Load Current

3.4 Power Adapter To verify our charging station was working as necessary, we performed two-stage experimentation. First, we wanted to ensure the power adapter was able to provide current of up to 2A as it had promised. To verify this, we connected 2.5Ω across the power supply and monitored the current

through the current transducer. After confirming this, we connected 10Ω resistor across each of the two DC male port and confirmed 500mA output current on each of the resistors.

12

After verifying testing on a dummy load, we performed further testing on the actual device to ensure charging rate of 500mA and have confirmed this requirement as seen in Figure 19. Lastly, we needed the power adapter to be sturdy to mechanically last long. We have done extensive tests on the DC male port with different strength to ensure it remains sturdy on the charging station clip and does not fall off from the clothing rack.

3.5 Lithium Polymer Battery To ensure that we are able to extract as much current from the battery as possible, we have done testing on the battery by discharging the battery to the load while implementing software revisions. As we have anticipated, the battery shut off when the voltage reached around 3.15V, which is a feature incorporated in the MCP73831 [3] called the under voltage lockout. When the UVLO circuit detects input voltage of a certain threshold, it shuts off MCP73831 until the input voltage rises above the UVLO threshold, which essentially cuts off power to the rest of the circuit. This feature is crucial, as lithium polymer battery may become permanently damaged with voltage levels less than 3.0V, rendering the device useless.

Another requirement of our battery was to operate around 60 degrees, since it is dangerous for lithium polymer battery to be operating in high temperature. To verify this, we simply pointed the IR temperature gun at the center of the lithium polymer battery and ensured that temperature was not getting hot when in charging mode and discharging mode. As anticipated the battery operated under room temperature

3.6 Power Circuit Power circuit was arguably the most crucial component inside our hanger for other components to function properly. Without stable voltage feeding our system, we could not have achieved any of the features that we wanted to implement. As this is the case, we made sure to always test the power circuit first before moving onto system component design and verification.

The waveform shown in figures 19 includes the output voltage of our buck-boost converter of 3.299V and battery charging current of 463.86mA. By implementing all of PCB design requirement as outlined by the IC manufacturer, such as creating ground planes and input/output planes, we were able to obtain output voltage that was very stable in operation, showing voltage ripple of only around .07V

13

Figure 18 Buck Boost Voltage and Charging Current

Last verification we needed to perform was to check the efficiency of the buck-boost converter to ensure we are operating at a high efficiency to conserve power for portability use. As shown in figures 20, we see that the datasheet claims efficiency of 91% with our given output load. To put this to the test, we used a simple equation to find the power efficiency, which is as follows:

η (efficiency) =𝑃𝑃𝑜𝑜𝑜𝑜𝑜𝑜𝑃𝑃𝑖𝑖𝑖𝑖

(1)

By inputting all the parameters into formula 1 through referring to figures 17 and 19, we were able to verify the converter to have efficiency of 89.5% during operation, which was above our requirement of 85% efficiency.

Figure 19 Buck Boost Efficiency Vs Output Current

14

3.7 LabVIEW Front End Application The front end application was arguably one of the most important feature in our design, as we wanted to solve the main problem of low employee productivity. First, we have claimed in our requirement that the application needed to be straightforward enough such that user without any prior experience/knowledge in programming or engineering could learn how to use the software with ease.

To verify this functionality, we searched and picked three people on campus without any engineering/programming background to test out our software. Our initial response from the first iteration of design was that it was hard to know what forms to fill out to correctly display the values onto the LCD display. To match our requirement, we’ve generated tabs on each functionality, much like how users surf the web. All the buttons and forms were placed with labels for intuitive operation. With few instructions given to the user, they were able to operate the hanger without any hiccups.

Next, we needed to ensure correct string packets were being sent out to the Wi-Fi module. To debug these values being sent out, we used a feature in LabVIEW called the wire probe and highlight feature, as shown in figures 21. By placing probes across wires similar to what you would do with voltage probes to see voltage level across electrical components, you can observe the values being sent to each “node” of the program. As with the highlight feature, LabVIEW takes you slowly from node to node to ensure your data operation and values are being calculated correctly. These features help the programmers easily debug their problems. We’ve used this feature many times to verify efficient transmission of data and stability of TCP connection.

Figure 20 Debugging: Probe and Highlight Feature

3.8 ADXL335 (Accelerometer) It is essential that the LCD displays is on only when it is being used by the user to save significant amount of power. To implement this power saving mode, we needed a sensor to detect movement of hanger to indicate when it is in use. In our application of the sensor, we needed it such that we can adjust the sensitivity levels. To test whether the ADXL provided these features as we required, we first calibrated the accelerometer to display the value in terms of gravity acceleration (g’s). The reason for this is that each accelerometer reads ADC value a bit differently to another from device to device depending on the

15

input voltage. Hence, we needed to calibrate and scale our value such that all of our hangers produced same results when user was interacting with the hanger.

After calibration of the accelerometer, we verified the functionality through different speed tests to ensure the sensitivity of the hanger was just enough such that it only turned into active mode when user picked up the hanger.

3.9 Like Button Since ‘Like’ button is an important feature in our design, we needed to ensure the button operated as we intended to. One of the things we needed to do was to debounce the switch. Without debouncing the switch, we noticed a multiple increment of the like value instead of incrementing by one as we had anticipated. To verify it only incremented once, we changed up the speed and duration of the press of button to ensure correct functionality every time.

Figure 21 Debounced Like Button

16

4. Costs Because our system requires user to buy multiple hangers, price was one of the most important design factors when developing our product. Table 2 outlines the cost of materials while Table 3 outlines the cost of labor. It is important to keep in mind that even if the price of individual hanger might seem expensive compared to a cheap normal hanger, this intelligent hanger system provides profitable features over a long term.

4.1 Parts

Table 2. Parts Costs

Part Manufacturer Retail Cost ($) Bulk Purchase Cost ($) Actual Cost ($)

Display (2.8inch TFT SPI LCD) AliExpress 8.06 4.30 8.06

Hanger Alibaba 3.00 0.75 3.00

Wi-Fi Module (ESP8266-01) Sparkfun 2.00 1.66 2.00

Battery (3.7 Li-Po Battery) Sparkfun 12.00 3.80 12.00

Microcontroller (ATMega328P-PU) Atmel 3.70 2.18 3.70

8MHz Crystal Oscillator Alibaba 0.38 0.04 0.38

Buck/Boost Converter (TPS63001)

Texas Instruments 2.36 1.06 2.36

Charge Management Control (MCP73831) Microchip 0.59 0.42 0.59

DC Male/Female Pin DigiKey 3.00 0.80 3.00

PCB FirstPCB 33.00 1.00 33

Accelerometer (ADXL335) Analog Devices 5.07 1.60 5.07

Resistor, Capacitor, Inductor DigiKey 4.20 1.40 4.20

Total - 77.06 19.01 77.06

* Note: USB FTDI Programmer is not included since it is a one-time development purchase

17

4.2 Labor Table 3. Labor Costs

Engineer Rate ( $𝑯𝑯𝑯𝑯𝑯𝑯𝑯𝑯

) Hours Total ($)

Chung, Won Ho 35 250 21,875

Kim, Min Kyun 35 250 21,875

Total - 500 43,750

The overall cost of this project was $77.06 + $43,750.00 = $43827.06. It is important to note that there is a huge cost reduction between the retail cost and bulk purchase cost. Considering the Smart Hanger’s benefits and features, large retail clothing store will be ordering bulk purchases, which will significantly lower manufacturing costs. In addition, about 45% reduction of retail price to actual cost is from the PCB cost since we used an American PCB manufacturer. By mass-producing our product, price to manufacture the PCB will decrease greatly by submitting order overseas.

4.3 Grand Total Table 4. Grand Total

Section Total ($)

Parts 77.06

Labor 43,750

Grand Total 43,827.06

18

5. Conclusion

5.1 Accomplishments By the end of this project, we had developed an intelligent and intuitive hanger system that accurately provide product information to customers and enhance overall store employee productivity. We were also able to design this Retail Smart Hanger with portability feature so that it can be used in all kinds of stores in various applications.

5.2 Uncertainties We are currently uncertain of the device’s durability in couple of aspect in our design. Since this product was created for prototyping, point of joints between the hanger hook and DC female power plug is not firmly attached for real use. Before this product is presented into the market, we must create a mechanically designed hanger hook and enclosure that will be durable with use.

5.3 Ethical considerations As an engineer to enhance the quality of life throughout the world, we will abide by the IEEE Code of Ethics [2] with emphasize on the following code below but not limited to:

1. To accept responsibility in making decisions consistent with the safety, health, and welfare of the public, and to disclose promptly factors that might endanger the public or the environment.

Since this project will be using wall outlet voltage, we will ensure that all power connection wires are properly insulated and concealed at exposed points to prevent getting electrocuted. In order to save the as much power as possible, we will make sure to assemble the device with low-powered components whenever possible and have device be turned off when in idle state.

3. To be honest and realistic in stating claims or estimates based on available data. Various experiments will be performed with the Retail Smart Hanger project to verify the requirements and provide the customers with most accurate and honest data. This will require honest and realistic attitudes in stating claims. Also, to keep the device from malfunctioning, powering data will be investigated strictly.

7. To seek, accept, and offer honest criticism of technical work, to acknowledge and correct errors, and to credit properly the contributions of others.

Purport of this project is to provide innovative hanger system for stores and seeking for productive criticism is vital to system development. We will be open to all critiques and feedbacks regarding this project.

5.4 Future work We believe that this innovative system has the potential to change the market and to save the environment. Once we take this product to market, we will work on further elaborating the user interfaces, decreasing the size of the encasing, reducing costs, optimizing power consumption, and integrating consumer review/rating system through social media. The possibilities are endless.

19

References [1] Chrisrust,”Burn Arduino Bootloader to ATMEGA328P-PU Using Arduino Pro Mini”, Instructables.

Available at: http://www.instructables.com/id/Burn-Arduino-Bootloader-to-ATMEGA328P-PU/. Accessed April 2016.

[2] Institute of Electrical and Electronics (IEEE), IEEE Code of Ethics, Online, IEEE Std., 2015. [Online]. Available at: http://www.ieee.org/about/corporate/governance/p7-8.htmlh.

[3] Miniature Single-Cell, Fully Intergrated Li-lon, Li-Polymer Charge Management Controllers, datasheet, Microchip, Inc., 2014. Available at: http://ww1.microchip.com/downloads/en/DeviceDo c/20001984g.pdf.

[4] TPS6300x High-Efficient Single Inductor Buck-Boost Converter With 1.8-A Switches, datasheet, Texas Instruments, Inc., 2015. Available at: http://www.ti.com/lit/ds/symlink/tps63001.pdf.

20

Appendix A

Table 5 System Requirement and Verification

Unit Requirement Verification Verification Status(Y/N)

Wi-Fi Module

1. Connect to wireless router network and transmit data within 20m of wireless access point

a) Post corresponding AT from at least 20m away from access point

b) Test string packet saved in local variable in microcontroller

Y

2. ESP8266 must be in deep sleep mode during standby mode

a) ESP8266 is in deep sleep mode during Standby Mode

b) ESP8266 must wake up from deep sleep in Active Mode and reconnect to LabVIEW

Y

3. Receive string packet of at least 50 characters

a) Check on TFT LCD to ensure data is properly transmitted Y

4. Operate at baud rate of 9600 for Software Serial to function

a) Run AT+CIPBAUD=9600 b) Check UART for correct baud rate Y

Micro controller

1. Boot load with 3.3V Arduino Pro Mini and be able to program flash memory

a) Boo load bare bone ATMega328P-PU

b) Program microcontroller with blinking LED example sketch and verify functionality

Y

2. It must be able to communicate with SPI peripheral

a) Include library files as provided by Adafruit’s TFT LCD library

b) Run graphic test example code on microcontroller

Y

3. ADC range of 0.0V to 3.3V± 5% with a precision of 3mV± 1%

a) Attach function generator on analog input pins 0, 1, and 2 and observe correct voltage level from 0V to 3.3V at 300mV increment

Y

4. Save information sent from LabVIEW into EEPROM to read value when power is shut off and read back values when power turns back on

a) Save values onto EEPROM starting at address 0 on EEPROM

b) Check that same values are displayed on LCD display when you power off and on your device

Y

LCD Screen

1. Input Voltage: 3.3V ±5%

a) Measure VCC using oscilloscope to verify voltage level Y

2. Display correct ASCII text as set in local variable

a) Use serial monitor and LCD monitor to visually verify correct text update

Y

Continued on next page

21

Table 5 - continued from previous page

Unit Requirement Verification Verification Status(Y/N)

Charging Station

1. 120V AC to 5V±0.5𝑉𝑉 DC

a) Connect voltage probe to VCC and GND of power supply and check voltage level on oscilloscope

Y

2. 500mA±50mA during active charging phase

a) Connect transducer to 10ohm resistor connected across power supply

b) Calibrate and verify value of 500mA±50mA

Y

Li-Po Battery

1. 3.7V Nominal voltage with charge cut-off voltage of 4.2V and minimum voltage of 3.0V

a) Discharge battery to minimum value and charge battery to cutoff voltage

Y

2. Temperature < 60°C

a) Use IR temperature digital gun to monitor temperature of battery during charging and discharging phase

Y

Power Converter

1. Input Voltage: 3.0V to 4.2V Output Voltage: 3.3V±5%

a) Probe input and output voltage to ensure buck-boost is operating within voltage specification

Y

2. 85% Efficiency for power efficient system when in portability mode

a) Use power efficiency formula in conjunction with power multimeter to obtain efficiency value

Y

Front End Application

1. Intuitive user interface which allows any novice user to post information with few steps

a) Request 3 people of different academic background/interest to verify usability without prior coding experience

Y

2. Initiate TCP connection to Wi-Fi module

a) Check access point has been created by checking serial monitor and typing AT+CIPSERVER?

Y

3. Security feature to prevent people without access to gain control of the application

a) Log in Prompt starts in beginning b) When user inputs wrong

ID/Password combination, warning prompt pop up to inform user of wrong ID

Y

Accelero- meter

1. Input voltage : 3.3V±0.3V a) Scope input VCC and make sure required input voltage is met

Y

22