Smart shoe

An-najah National University
Engineering Collage
Electrical Department
Supervisor: Dr. Ra'ed Jaber
Prepared By: Sa'ed Qariab
Mos'ab Naffa
SEMINAR 1 SMART SHOE

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Table Of CONTENTS
Table of contents................................................................................................................................................................1
List of Figures...........................................................................................................................................................................3
List of Tables.............................................................................................................................................................................4
List of Nomenclatures .........................................................................................................................................................5
Acknowledgement.................................................................................................................................................................6
Abstract.......................................................................................................................................................................................7
Chapter 1: Introduction .....................................................................................................................................................9
1.1 : Statement of problem ................................................................................................................................................................9
1.2 : Purpose ............................................................................................................................................................................................9
1.3 : Objectives.......................................................................................................................................................................................10
1.4 : Scope of work ............................................................................................................................................................................11
Chapter 2:Constraints and earlier work................................................................................................................12
2.1 : Constraints ................................................................................................................................................................................12
2.2 : earlier coursework.................................................................................................................................................................12
Chapter 3: Literature review.......................................................................................................................................13
3.1 : Citation relevant work and results .....................................................................................................................................13
3.2 : Theoretical background .........................................................................................................................................................13
Chapter 4: Methodology: ...............................................................................................................................................14
4.1 Block Diagram: ...............................................................................................................................................................................14
4.2 Block Diagram Description: ......................................................................................................................................................15
4.2.1 Google Mapping Database: .....................................................................................................................................................15
4.2.2 Android Application Unit:........................................................................................................................................................15
4.2.2.1 Accessibility Service : ..........................................................................................................................................................15
4.2.2.2 Android Application:..............................................................................................................................................................15
4.2.3 Bluetooth Unit:..............................................................................................................................................................................16
4.2.4 Microcontroller Unit: ................................................................................................................................................................16
4.2.5 Vibration Motor Unit: ...............................................................................................................................................................17
4.2.5.1 Coin Vibration Motor : ...........................................................................................................................................................17
4.2.5.2 N-Channel MOSFET: .............................................................................................................................................................18
4.2.5.3 Pull-Down Resistor :...............................................................................................................................................................18
4.2.6 Pressure Sensing Unit: .............................................................................................................................................................18
4.2.6.1 FSR (Force Sensor): ................................................................................................................................................................18
4.2.6.2 27KΩ Resistor: .....................................................................................................................................................................19
4.2.7 Power Unit :....................................................................................................................................................................................19
4.2.7.1 Lithium Polymer (LiPO) Battery: .....................................................................................................................................19
4.2.7.2 Step-Up/Step-Down DC-DC Converter : .......................................................................................................................20
4.2.7.3 Charging Circuit: ......................................................................................................................................................................20
4.2.7.4 Charging Port:............................................................................................................................................................................21
4.2.7.5 USB Charging Cable: ..............................................................................................................................................................21

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4.2.7.6 Switches:....................................................................................................................................................................................21
4.2.8 Shoe: ..............................................................................................................................................................................................21
4.3 Design:................................................................................................................................................................................................22
4.3.1 Google Mapping Database: ...................................................................................................................................................22
4.3.2 Android Application Unit:.....................................................................................................................................................22
4.3.3 Bluetooth Unit: ..........................................................................................................................................................................24
4.3.4 Microcontroller Unit :..............................................................................................................................................................25
4.3.5 Vibration Motor Unit: ............................................................................................................................................................26
4.3.6 Pressure Sensing Unit :.........................................................................................................................................................28
4.3.7 Power Unit: ................................................................................................................................................................................29
4.4 Shoe Layout :..................................................................................................................................................................................30
4.4.1 Mounting Vibration Motors :...............................................................................................................................................31
4.4.2 Mounting FSRs: .......................................................................................................................................................................32
4.4.3 Mounting Charging Socket :.................................................................................................................................................33
Chapter 5: Results And Analysis.................................................................................................................................34
5.1 Elements Pins and Power : .........................................................................................................................................................34
5.1.1 HC-06 Bluetooth: ........................................................................................................................................................................34
5.1.2: Vibration Motors :......................................................................................................................................................................35
5.1.3 Pressure Sensing Units : ............................................................................................................................................................35
5.1.4 Arduino Pro Mini : ......................................................................................................................................................................36
5.1.5 Power Unit :.....................................................................................................................................................................................37
5.2 Power Budget : .................................................................................................................................................................................38
Chapter 6: Conclusion ...................................................................................................................................................40
6.1 Accomplishments: ........................................................................................................................................................................40
6.2 Uncertainties : .................................................................................................................................................................................40
6.3 Ethical Consideration : .................................................................................................................................................................41
6.4 Project Feasibility : .........................................................................................................................................................................42
6.5 Future Work : ..................................................................................................................................................................................43
References ............................................................................................................................................................................44
Appendences ........................................................................................................................................................................45
Schematic Circuit Diagram: ...............................................................................................................................................................45
Arduino Circuit (pins): ........................................................................................................................................................................46
Bluetooth circuit (pins): ......................................................................................................................................................................47
Attachment(A) ...................................................................................................................................................................48

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Table of Figures:
Figure 1: General Block Diagram ........................................................................................................................14
Figure 2: HC-06 Bluetooth ......................................................................................................................................16
Figure 4: Coin Vibration Motor.............................................................................................................................17
Figure 3: Arduino Pro Mini.....................................................................................................................................17
Figure 5: FSR.................................................................................................................................................................18
Figure 6: LiOP Battery..............................................................................................................................................19
Figure 7:MAX 710.......................................................................................................................................................20
Figure 8: Charging Circuit ......................................................................................................................................20
Figure 9: Overall Control Flow for Android Application..........................................................................23
Figure 10: Arduino Pro Mini and HC-06 Schematic.....................................................................................24
Figure 11:Contents of Bluetooth Message........................................................................................................25
Figure 12:Vibration Motor Schematic...............................................................................................................27
Figure 13: Pressure Sensor Schematic...............................................................................................................28
Figure 14: Power Unit...............................................................................................................................................29
Figure 15: Layout of Vibration Motors inside the shoe ..............................................................................31
Figure 16:Layout of Pressure Sensors inside the shoe ................................................................................32
Figure 17: USB Charging Cable and Charging Socket ................................................................................33
Figure 18: Schematic Circuit Diagram..............................................................................................................45
Figure 19 :Arduino Pro Mini Circuit..................................................................................................................46
Figure 20:Bluetooth Circuit...................................................................................................................................47

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List of Tables:
Table 1: HC-06 Bluetooth power..........................................................................................................................34
Table 2: Vibration Motors Power.........................................................................................................................35
Table 3: FSR Power....................................................................................................................................................35
Table 4: Arduino pro Mimi power........................................................................................................................36
Table 5: Power Unit ...................................................................................................................................................37
Table 6: Poewr Budget .............................................................................................................................................38

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List of Nomenclatures :
*Mobile App: programmable application for smart phones(Android and iOS).
*Android/iOS: programming languages and launchers for smart phones.
*BLE: Bluetooth low power consumption
* LiPO : Lithium Polymer Battery
*FSR : Force Sensing Resister
*VM: Vibration Motor

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Acknowledgement
We take this opportunity to express our profound gratitude and
deep regards to our guide Dr. Ra'ed Jaber for his exemplary
guidance, monitoring, continued support and constant
encouragement throughout the course of this project.

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Abstract
The world is getting bigger and bigger, and the technology is invading the
globe to comfort the human being, and technology still seeking new products
to make life much and much easier, and we as engineers this is one of our
tasks.
Every day we hear the word 'smart' in everything that the technology has
produced such like Smart phone, Smart car and Smart TV, so why not a Smart
shoe ? Okay, we are going to make a Smart shoe ! Yes it's that simple, a smart
shoe that would lead you to any place you want to go, of course by using help
from the Smart phones.
Our project would revolve about coming with a prototype for a smart shoe
that could pair with Smart phones by using Bluetooth, to reach the
navigational information through a mobile app to get these information and
instruction from Google map's database.
In a matter of fact, this smart shoe could give indications for the user of this
shoe when and where to take a turn and also the type of the turn. All these
indications would be relayed by six vibrating units (motors) placed inside the
shoe in the six directions up,down,left,right,front and back ,these units would
take the instruction through a microcontroller located inside the shoe, that
already would be paired with a smart phone by Bluetooth.
So we designed the whole project block diagram and the circuits for each
section of the diagram as a complete system. Thus, the data for navigation will
be taken from the Google's map database and processed by the mobile App
and transmitted through the Bluetooth to the microcontroller to give
instructions for the vibration units to guide the user for the desired route.

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We made some calculation for the power consumption and for the sizes for
the components. The results were satisfying, where we can use the shoe up to
one day ,and the components can fit in the shoe as we aiming to build a
prototype with regular items.

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1. Introduction
We successfully designed the circuits and the layout for Smart
Shoe. Smart Shoe provides a reliable and unique way for indoor and outdoor
navigation relying on the idea of haptic feedback. Our design also integrates
detailed pressure sensing to give accurate information about a person’s feet
movements and feet pressure distribution while walking, jogging or running.
With support for USB charging, this product represents a complete and
marketable final product. We believe that our product will cater to the vast
number of people who use their Smartphones for navigation, athletes and the
common masses.
1.1 Statement of problem
Smartphones have been an excellent asset for navigation in the past couple of
years and companies such as Google have come up with some really
impressive navigation solutions. Although, these Smartphones assist us with
both outdoor and indoor navigation, they still impose a restriction which is
the necessity of holding them/looking at their screens or listening to them to
get directions, also there's a lot of people don't know how to use the
navigation system in the smart phone and sometimes they get confused which
way is the left or the right. Moreover, deaf people can't hear the instructions
from their phones.
1.2 Purpose
We seek to overcome this challenge by proposing a novel way of how these
navigation directions are relayed to us from Smartphones using an
underappreciated wearable: the shoe.
Our project would revolve around coming up with a smart shoe prototype that
could pair with Smartphones using Bluetooth and help provide navigational
information through vibration units placed all around the shoe. In essence,
these shoes could give indications about when to take a turn, where to take a
turn and the type of turn to take to the person wearing these smart shoes. All
this information would be

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relayed through 6 vibration units located in the bottom, top, front, and back,
left and right segments of the shoe representing the 6 directions that one
could go in. There would be a microcontroller connected to a Bluetooth trans-
receiver that would send signals to the vibration units based on information
received.
This new and distraction-free way of navigation will certainly help in
providing directions using something that we all definitely use especially if
we’re navigating. Using Google’s navigation database, we can not only provide
information for outdoor but also indoor navigation. Imagine the convenience
of walking to your departure gate at the airport without having to use your
Smartphone or any other directions at all.
Also imagine the convenience of being directed to the nearest Starbucks in
the terminal when you’re feeling hungry without looking around at all!
Sometime in the future, when indoor mapping becomes more widespread,
imagine walking straight to the Apples section in a supermarket from your
hotel in a foreign country without looking around or peeking into your
Smartphone screen! All of this and a lot more is possible with the help of
Smart shoe.
1.3 Objectives
Goals and Functions :
Our project goal is to develop a prototype that uses vibration motors to relay
navigation instructions obtained via Bluetooth from a Smartphone. We seek to
develop a mobile app that leverages navigational information from Google’s
indoor and outdoor mapping database and sends this information via
Bluetooth to a micro-controller. Our project would also involve programming
a microcontroller to connect with a Bluetooth Chip via the serial cable to
receive messages and control the vibration motors accordingly. Based on the
instructions received, the microcontroller would create different vibration
patterns to guide the user to his/her destination. A significant part of this
project would also be focused on developing the circuitry required to provide
different components with the right voltage, power for the required amount of
time.

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Features
 Android Application/Accessibility Service to retrieve Navigational
instructions
 Support for both Outdoor and Indoor Navigation
 Bluetooth Low Energy Chip to send/receive directional information
 Control of 6 Vibration Motors
 Vibration Intensity Control
Benefits
 Navigational Assistance while travelling
 Distraction-free travel
 Automatic rerouting and alerts
 Various User-controlled Vibration patterns
 Precisely Calculates pressure distribution on different areas of your feet.
1.4 Scope of the work
In this project ,our work will be concentrated on making a complete design
for the prototype for the shoe with all the components inside it, and to be
perfectly distributed in the shoe without affecting the feet.
On the other side, we have a serious challenge which is to make the circuit
small and to choose the smallest components as possible as we can to fit in
the shoe as a primitive prototype design made by our hands, and in the long
term to be abroad manufactured.

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2.Constraints and Earlier coursework
In this chapter we will go through some constraints and obstacles that we
have faced through studying and analyzing this project. Besides, the
international codes we used and any earlier work for this project.
2.1 Constraints
As any project or work you do in your life, you should face some obstacles
while doing it. At first, we encountered the problem of limited elements we
need for the project, but we have got over it by finding a shop that has what
the project requires from the unique components.
2.2 Earlier coursework
We took a course called (Microprocessors and controllers ) which is a 3 credit
hours, we learned how to program the controller .We also made a project to
detect the distance by using the Microcontroller and Ultrasonic sensor. In
addition to the Electronics 1,2,3 and electronics lab ,where we made a circuit
to amplify the sound wave by using many techniques.

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3. Literature review
3.1 Citation relevant work and results
Our project is kind of unique, and its idea has no one ever done it completely.
We did a search for any earlier match work or the same, we found that Apple
company by cooperating with Nike company has a similar idea, but it's not
exactly the same as ours .
Apple's idea is a small device that you put in some specific kinds of shoes that
made especially by Nike for this device, this device only calculate the distance
that you run and how much Calories that you have lost through pairing with
your iPhone.
We also found that some students in India are trying to make something that
looks almost as our project, and they are trying to produce it by factories, but
they have not done completely.
3.2 Theoretical background
From the expertise that have been gained through past courses, it was easier
to deal with the project. Our project almost depends on the controllers and
electronic elements, and they already have been mentioned in different
courses such as Microcontrollers and processers, Electronic circuits.
Many other courses helped us in performing this project such as Control
systems and electronics lab.

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4. Methodology
This chapter will show the General Block Diagram for the project, and the
design we made including the layout of the shoe.
4.1 Block Diagram
Figure 1: General Block Diagram

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4.2 Block Diagram Description:
4.2.1 Google Mapping Database
Google has an extensive mapping database for both outdoor and indoor
purposes. This information will be leveraged by the android application to
calculate control signals for the vibration motors. Navigation Notifications
from the Google Mapping Database will be sent over to the Android
Application depending on user location.
4.2.2 Android Application Unit
The Android application consists of two components: Accessibility Service and
Android Application. This unit is responsible for handling Bluetooth
Communication with the microcontroller, sending motor control signals and
receiving pressure sensing information. And finally sending signals for
comforting the user as an extra feature such like a massage for the user's feet.
4.2.2.1 Accessibility Service
The Accessibility Service runs in the background and syncs with the Bluetooth
unit whenever in close proximity. It receives navigation notifications from
Google Maps application and calculates control signals of the 6 vibration units
which are then sent over to the microcontroller. It also retrieves live and
aggregated pressure sensing information from the microcontroller and stores
it locally on the Smartphone.
4.2.2.2 Android Application
The Android Application displays current and aggregated feet pressure
distribution received from the microcontroller and calculates various walking
attributes such as steps walked, distance travelled and speed.

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4.2.3 Bluetooth Unit
The Bluetooth Unit was changed from TI-CC2541 BLE chip to HC-06 Bluetooth
Module to ensure compatibility with all Bluetooth supported Smartphones.
With support for Bluetooth 2.0, this module helps in sending and receiving
messages from android application to microcontroller and vice-versa. The
Bluetooth Unit requires 3.0 – 6V for optimal performance and it syncs with a
Bluetooth device within a distance of 5 ft. According to Datasheet [8], this
Bluetooth module encompasses all the aforementioned features.
Figure 2: HC-06 Bluetooth
4.2.4 Microcontroller Unit
The Microcontroller Unit consists of an Arduino Pro Mini 5V/16Mhz. A
decision was made to go for the Arduino Pro Microcontroller to provide for a
distributed arrangement of components for improving ergonomics in the final
product.
The Microcontroller receives control signals from the Android Application
through the Bluetooth Unit and sends control PWM signals to the different
vibration motors. It also measures voltage across the three Force Sensitive
Resistors (FSR) and calculates current and aggregated feet pressure
distribution on the arches and heel. All this information is relayed back to the
Android application through Bluetooth. The Arduino Pro Mini requires an
operating voltage of 2.7 – 5.5V to function correctly. Analog Input from the
Pressure Sensing Units should be measured by the microcontroller with 0.01V

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accuracy. According to Datasheet [9], the Arduino Pro Mini is able to provide
this accuracy.
4.2.5 Vibration Motor Unit
The Vibration Motors Unit consists of 6 vibration motors placed around the
shoe that provides haptic feedback to guide the user in different directions
based on PWM input signals from the microcontroller.
4.2.5.1 Coin Vibration Motor
Our Design contains six Coin Vibration Motors placed at the top, bottom, left,
right, front and back of the shoe in order to provide corresponding directional
output vibration impulses. Since, these motors have to be placed inside the
shoe it is very important that they are lightweight, compact and consume
minimal energy while still being able to provide sufficient vibration output.
We used 310-313 Pico Drive Vibration Motors for this purpose. According to
Datasheet [2], these Vibration Motors provide for the aforementioned
features.
Figure 4: Coin Vibration Motor
Figure 3: Arduino Pro Mini

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4.2.5.2 N-Channel MOSFET
Our design uses six N-Channel MOSFETs that control the six motors through
the PWM output coming out from the Microcontroller. It takes in 3.3V drain
voltage from the power supply and PWM outputs serve as Gate Voltage. We
chose N-Channel MOSFETs over P-Channel MOSFETs since it is more cost
effective and more efficient when operating in the saturation region. We used
NDS331N to make it compatible with our compact design and consume less
power. Datasheet [10] details more information about NDS331N in this
regard.
4.2.5.3 Pull-Down Resistor
Our design uses six pull down resistors each of R= 50kΩ which reduces the
quiescent current.
4.2.6 Pressure Sensing Unit
The Pressure Sensing Unit is responsible for taking in pressure inputs from
the feet and relaying them to the microcontroller.
4.2.6.1 FSR (Force Sensor)
Our design contains three Force Sensitive Resistors laid out so as to measure
foot pressure distribution for the arches and heels. We chose FSR 400 for our
design. We wanted the FSRs to have direct contact with the foot and
adequately cover the respective pressure points for accurate pressure
measurement without discomforting the user. According to Datasheet [3], FSR
400 met these specifications.
Figure 5: FSR

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4.2.6.2 27KΩ Resistor
Our design contains three 27 KΩ Resistors each of which are placed in series
with the FSRs. 27 KΩ Resistors provide a voltage sweep from 0V to 5V across
the FSRs when the resistance varies between 0 – 100kΩ.
4.2.7 Power Unit
The power unit is responsible for providing regulated 3.3V to the Bluetooth
Chip and Vibration Motor Unit and 5V to the Pressure Sensing Unit and
Microcontroller. It is also essential that it provides adequate power to all the
components for at least 24 hours when fully charged. We also added support
for USB Charging.
4.2.7.1 Lithium Polymer (LiPO) Battery
We changed our initial battery design from a parallel combination of three LIR
2450 button cells to a 3.7V 850mAh LiPO battery in order to make all the
components run for a longer time. The small size of the battery helped in
making the design more compact. According to datasheet [4]
Figure 6: LiOP Battery

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4.2.7.2 Step-Up/Step-Down DC-DC Converter
We replaced the initially chosen MAX779CSA step-up DC-DC converter with
the MAX 710 Step-Up/Step-Down DC-DC converter for the 5V power supply
and added another MAX710 Step-Up/Step-Down DC-DC converter for
providing regulated 3.3V power supply. The MAX779CSA step-up DC-DC
converter required at least a 50mA current draw which was above our
maximum current draw for the 5V power supply. We used Step-Up/Step-
Down topology because our battery voltage varied between 3.2V and 4.2V and
a step-down converter by itself could not suffice the 3.3V power supply
requirement. According to datasheet [5]
Figure 7:MAX 710
4.2.7.3 Charging Circuit
The Charging Circuit is responsible for providing fast and easy USB charging
for the LiPO battery. It consists of a LTC1734L DC charging chip. The
LTC1743L DC Charging chip takes in regulated 5V power supply from a USB
Charging Cable and charges the battery until it reaches its maximum power
capacity. According to datasheet [6]
Figure 8: Charging Circuit

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4.2.7.4 Charging Port
A Charging Port located on the side of the shoe provides for an easy plug for
the USB charging cable.
4.2.7.5 USB Charging Cable
A Special USB Charging Cable with two pins that can go into the Charging Port
provide easy USB charging.
4.2.7.6 Switche
The product features a switch for turning on/off the device.
4.2.8 Shoe
All our components are embedded inside a large size pair of shoes. The large
size of the shoe, its wide girth and its low cost made it really viable for our
purpose.

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4.3 Design
4.3.1 Google Mapping Database
Google has an extensive mapping database for both outdoor and indoor
purposes. This information is leveraged by the android application to
calculate control signals for the vibration motors. Navigation Notifications
from the Google Mapping Database will be sent over to the Android
Application depending on user location. The reason why Google Mapping
Database was chosen over other options such as Nokia HERE maps or Apple
Maps was because of the ease of integration of various navigational
capabilities into an Android Application. Google Mapping database also has
comparatively far broader and detailed coverage for both outdoor and indoor
maps. Another important reason why Google Mapping Database was used was
because of its usage of various experimental features such as Wi-Fi-GPS in
indoor navigation which deal with GPS inaccuracy problem indoors.
4.3.2 Android Application Unit
The project involved using a Smartphone application based on the Android
environment to communicate with the microcontroller using Bluetooth. Other
alternatives include iOS or Windows Phone Smartphone applications. An
Android Application was chosen over its other alternatives because of its
extensive and detailed support for various Google Maps navigation features.
The ease of application development arising out of the familiarity with the
Android development environments was another key reason why it was used
for this project.
Figure (9) shows the overall flow of control between different subcomponents
of the Android Application Unit. The accessibility service takes in notifications
generated from the Google Maps application, processes them and generates
the control signals which are then sent over Bluetooth to the microcontroller.
The Accessibility service is also responsible for managing Bluetooth
connectivity with the Bluetooth module. It automatically connects to it

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whenever it’s in range. After pairing is complete, pressure sensing information
from the microcontroller is relayed over Bluetooth to the accessibility service
which then logs all the information for further use by the Android Application.
The android Application displays current and aggregated pressure sensing
information.
Figure 9: Overall Control Flow
for Android Application
We decided to go for stages in vibration alert system for notifying the user of
an impending turn. The motors are vibrated for a period of 1 sec, 3 sec and 5
sec at a distance of 10m, 20m and 30m from the turn. A destination arrival
vibration comprised of simultaneous vibration of all motors. Notifications
were also sent out in cases of Loss of GPS accuracy and Rerouting.

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4.3.3 Bluetooth Unit
Our Bluetooth unit comprises of an HC-06 Bluetooth module (shown in Figure
2) which communicates over serial connection with the Arduino Pro Mini.
The detailed pin-level connections between the Arduino and the HC-06
Bluetooth module are (shown in Figure 10) The HC-06 Bluetooth Module is
powered by regulated 3.3V power supply from the power unit. Figure (11)
shows the format of the Bluetooth Message sent out from the Accessibility
Service to the Microcontroller. The contents of the Bluetooth Message packet
are minimized to ensure that Bluetooth power consumption is kept to a
minimum. Offering support for Bluetooth v2.0, the HC-06 Bluetooth module
ensures compatibility with most Smartphones out in the market today.
Figure 10: Arduino Pro Mini and HC-06 Schematic

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Figure 11:Contents of Bluetooth Message
4.3.4 Microcontroller Unit
The Microcontroller Unit comprises of the Arduino Pro Mini 5V/16Mhz
(shown in Figure 3). It supports 6 PWM outputs, UART and I2C
communication interfaces and up to 6 analog inputs. This makes the Arduino
Pro Mini well suited for the requirements of the device. The small size of the
Arduino Pro Mini suits our compact distributed design. Running at a clock
cycle of 16MHz, this microcontroller receives instructions from the Bluetooth
chip through UART and controls each of the motors for the required amount
of time. In essence, the microcontroller relays navigational directions to
different motors based on the vibration pattern customized by the users.
Messages received from the Bluetooth Unit are processed by the Arduino
using the Arduino Software Serial Library. Figure (11) describes the message
format received from the Android Application. The message is decoded and
various Vibration Intensities are converted to their respective PWM control
signals for the 6 vibration motors .

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4.3.5 Vibration Motor Unit
The 6 vibration motors in this unit are controlled by PWM signals from the
microcontroller. The coin vibration motor 310-330 PICO DRIVE (shown in
Figure 4) were easy to layout around the shoe without taking up too much
space or significantly increasing the weight of the shoe. Figure (12) shows the
schematic for driving a single vibration motor unit. According to Datasheet
[2], the Arduino Pro Mini has peak current capacity of 50mA. One vibration
motor requires 60mA to be driven at peak intensity. Consequently, the total
current draw for this unit is 360mA when all motors are vibrating at peak
intensity which is beyond the maximum current draw for the Arduino Pro
Mini. To overcome this shortcoming, we had to use an N-MOSFET to drive the
vibration motor.
The purpose of the N-Channel MOSFETs is to act as switch. N-Channel
MOSFET act as switch when operating in the saturation region. The saturation
region for the N-Channel MOSFET is governed by the conditions: V (GS) > V
(TH) and V (DS) > V (GS) - V (TH). The gate is connected to the PWM output of
the microcontroller, the drain is connected to the motor and the source is
grounded. In our design, V (DS) = 3.3V provided by the power unit. Therefore,
when PWM output of the microcontroller is greater than Vth transistor is
switched on and current is able to flow through the motor.

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We can vary the current flowing through the motor, and therefore the voltage
drop across it, by varying the PWM output voltage of the microcontroller. This
feature allows us to provide vibration impulses of different magnitudes based
on PWM control. Figure (12) shows the schematic for driving one vibration
motor.
Figure 12:Vibration Motor Schematic

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4.3.6 Pressure Sensing Unit
the foot and relaying them to the microcontroller. As shown in Figure 5, we
use FSR 400 to sense foot pressure. As pressure is applied on the FSR the
resistance of the FSR and the voltage drop across it decreases. Our design has
three FSR’s which are laid out so as to measure foot pressure distribution for
the arches and heels.
Figure (13) shows the schematic for measuring the output from one FSR. The
5V (Vcc) is provided by the power supply. The FSR is placed in series with a
27kΩ resistor and the voltage drop across the Force Sensitive Resistor is
measured by connecting it to the analog I/O port of the Microcontroller. 27 KΩ
Resistors provide a voltage sweep from 0V to 5V across the Force Sensitive
Resistor when the resistance varies between 0 – 100kΩ.We included 27 KΩ
resistor in our design to reduce current draw and power consumption making
sure that the microcontroller could measure the voltage across the FSR. The
maximum power consumption of each FSR was brought down to 0.926mW.
Figure 13: Pressure Sensor Schematic

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4.3.7 Power Unit
The power unit is responsible for providing regulated 3.3V + 5% and 5V +
5%power supply to other components of the circuit. We also added the circuit
to support charging via a USB cable to provide a convenient way of charging
our battery without having to remove the battery.
The maximum current draw from our circuit is 400mA when all the six motors
are running. Even though, this current draw lasts for only a few seconds when
a person is close to the destination or is being rerouted, we wanted to make
sure that our battery was capable of handling such a load. As shown in Figure
15, we use 3.7V/850 mAh Lithium-Ion Polymer (LiPO) battery in our design.
Under average load conditions, the battery should last for 24 hours once
completely charged.
In order to provide regulated 3.3V + 5% and 5V + 5%, we used two MAX710
Step up/down DC-DC converters. Figure (14) shows the schematic for a
MAX710 chip. Both the converters get power supply directly from the battery.
Figure 14: Power Unit

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The 5V + 5% output from one converter is used to provide power to the
Arduino Pro mini and the Pressure Sensing unit. The 3.3V + 5% output from
one converter is used to provide power to the Bluetooth Unit and the
Vibration Motor Unit. We used MAX710 because it had preset 3.3V and 5V
output, so we didn’t have to add additional circuitry to obtain the desired
output voltage. In addition, its low power consumption and packaging made it
appropriate for our compact design.
We also designed a USB charging circuit using a LTC1734L Lithium Ion Linear
Battery Charger. Figure(14) shows the schematic for LTC1734L. According to
Datasheet [6], the maximum charging current for the charger is 180mA. Even
though we could have chosen battery chargers with higher charging current
capabilities, we chose this as a safety measure to ensure that the battery did
not get over-heated while charging.
4.4 Shoe Layout
All components of our project were placed inside the right shoe of a pair of
large Size Shoes. Several modifications were made to the shoe to embed all the
components inside the shoe’s sides and sole. Figure (15) shows our final
product with all the components placed inside the shoe.
The Battery, Arduino Pro Mini, the HC-06 Bluetooth module will be
embedded under the fabric lining the interior sides of the shoe. The fabric
lining the sides was sliced up and the components were laid out in space
between the leather sides and fabric. To ensure a robust design, we will tap
down all the components and connecting wires and uniformly add padding to
reinforce the comfort level for the shoe. The fabric covering will be glued
down to increase the aesthetic appeal of the shoe.

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4.4.1 Mounting Vibration Motors
The six vibration motors were placed at the front, back, left, right, up and
down sides of the shoe as shown in Figure (15) representing the six basic
cardinal directions.
Figure 15: Layout of Vibration Motors inside the shoe

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4.4.2 Mounting FSRs
Three slits were made through the insole at the two arches and heel. FSR’s
were slid through the slit to ensure that only the head was visible and was in
direct contact with the foot as seen in Figure (16).
Figure 16:Layout of Pressure Sensors inside the shoe

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4.4.3 Mounting Charging Socket
5V input power supply to the charger is provided by a USB cable through a
two-pin charging socket that is placed on the side of the shoe as shown in
Figure (17). This will be made by drilling a small hole onto the side of the
shoe. The USB cable will also be specially designed to ensure stable and easy
connection with the charging socket.
Figure 17: USB Charging Cable and Charging Socket

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5. Results And Analysis
In this chapter we will show the results that we have obtained through
preparing the project, the complete schematic circuit and the pins that used
for the project to be done, and also the most important part the power budget
for the project.
5.1 Elements pins and power
5.1.1 HC-06 Bluetooth
This Low Energy Bluetooth supports Bluetooth 4.0 standards and pairs with
a Smartphone to receive encrypted message packets. The same information is
relayed to the microcontroller using serial connectors TX and Rx. The
decoding of messages is done by the Microcontroller using the Arduino
Software Serial library. This BLE chip has an extremely small power
consumption and high reliability for Bluetooth communication. Data from the
Android application is sent over to the Bluetooth chip only when necessary to
remove any unnecessary consumption.
Table 1: HC-06 Bluetooth power
Inputs Outputs
From Power Unit
 3.3V power ( PIN 12 )
 GND ( PIN 13 )
To Microcontroller Unit:
 Serial Data COM RF_N ( PIN 2 ) D0
 Serial Data COM RF_P ( PIN 3 ) D1

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5.1.2 Vibration Motors
This unit contains 6 vibration motors distributed in 6 locations inside the shoe
to represent the 6 navigation directions to be followed: move forward, move
backward, move up, move down, move right, move left. These motors are
controlled the microcontroller depending on the distance from a turn and the
direction of the turn to take.
Table 2: Vibration Motors Power
Inputs Outputs
From Power Unit
 3.3V power
 GND
N/A
From Microcontroller Unit
 FRONT VM
 BACK VM
 UP VM
 DOWN VM
 LEFT VM
 RIGHT VM
5.1.3 Pressure Sensing Units
the foot and relaying them to the microcontroller.
The Force Sensing Unit consumes max power when the resistance of the Force
Sensitive Resistor is almost 0.Therefore, max power per Force Sensitive
Resistor = V2/ R = 25 / 27K = 0.926 mW.
Table 3: FSR Power
Inputs Outputs
From Power Unit
 5V power
 GND
To Microcontroller Unit
 FRONT FSR (PIN 23)
 BACK FSR (PIN 24)
 Middle FSR (PIN 25)

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5.1.4 Arduino Pro Mini
The Microcontroller supports 6 PWM outputs, UART and I2C communication
interfaces. Running at a clock cycle of 16MHz, this microcontroller receives
instructions from the Bluetooth chip using either UART or the I2C interfaces
and controls each of the motors for the required amount of time. In essence,
the microcontroller relays navigational directions to different motors based
on the vibration pattern customized by the users.
Table 4: Arduino pro Mimi power
Inputs Outputs
From Power Unit:
 5V power ( PIN 7 )
 GND ( PIN 8 )
To Vibration Motor Unit:
 FRONT VM : PWM (PIN 5)
 BACK VM : PWM (PIN 11)
 UP VM : PWM (PIN 12 )
 DOWN VM : PWM (PIN 15)
 LEFT VM : PWM (PIN 16 )
 RIGHT VM : PWM (PIN 17)
From Bluetooth Chip:
 Serial Data COM RXD ( PIN 2 )
 Serial Data COM TXD ( PIN 3 )
From Pressure Sensing Unit:
 FRONT FSR : Analog I/O PIN 23
 BACK FSR : Analog I/O PIN 24
 Middle FSR : Analog I/O PIN 25

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5.1.5 Power Unit
The power unit is responsible for providing adequate voltage supply, 3.3V and
5V, to power Vibration Motor Unit, Pressure Sensing Unit, BLE Chip and
Microcontroller. It is also essential that it lasts for at least 24 hours and up,
and it has a capacity rating capable of handling the current requirements.
Table 5: Power Unit
Inputs Outputs
To Microcontroller
 5V Power Supply
 GND
To Pressure Sensing Unit
 5V Power Supply
 GND
To Vibration Motor Unit
 3.3V Power Supply
 GND
To BLE chip
 3.3V Power Supply
 GND

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5.2 Power Budget
Table 6: Poewr Budget
Vibration Motor:
 160mW when running
 0mW when stopped
 Average Power Consumption :
1) Assuming the motor vibrates for (3-5) second every 20 seconds.
2) For 1 minute it will vibrate 3 times for 15 sec.
3)For 1 hour 900 vib*hour
4)power for the VM mW/h:
P=160/(60*60)=0.04 mW/h
Average power consumption =900 * 0.04= 36 mW
Microcontroller:
 5mW when on
 Average Power Consumption : 5mW
 (Assuming microcontroller is on all the time)
BLU Chip:
 86.4mW when sending/receiving messages
 3.24μW when in sleep mode
 Average Power Consumption : 17.28mW
 (Assuming Messages are sent/received once every 5 sec).
Pressure Sensor:
 2.775mW at maximum feet pressure
 0.24mW at minimum feet pressure
 Average power consumption : 1.38mW
 (Assuming a person lifts his feet uniformly)
Total Power: 72.73mW

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Total energy stored in the battery : 850mAh = 3.7*850 = 3145 mWh
Average Battery life=
Total energy stored in battery/Total average power consumption
= 3145/72.73 = 43.24212
1 day 19 hours 24 minutes and 20 seconds

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6. Conclusion
6.1 Accomplishments
We had several accomplishments throughout the semester. After getting our
project idea approved, we started working on getting a proof of concept (POC)
for our navigational guidance capability. We created a design for each circuit
in the project .In addition to make each circuit work perfectly we read every
component datasheet so we can make them work in optimum operation as
much as we can.
Our biggest achievement for this project was how to get everything assembled
inside a shoe. We spent a lot of time trying to add user comfort and how to
make the product look nice. We added in charging socket on the side so that
the product looked more complete and finished. We also added in a special
USB Charging Cable to add to the ease of charging for our finished product.
6.2 Uncertainties
Although our design is extremely light weight and compact, we are not sure if
the users will become used to the added weight if these components are
added to the shoe. We did several tests with the shoe which we added a
weight exactly the same of our circuit's weight. We found out that, initially, the
added weight is very evident but after some time the user tends to forget
about it and become accustomed to it. However, these results could be
different for different people and we will have to perform further tests to
ensure the device is not causing any distraction or discomfort.

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6.3 Ethical Consideration
For this project, we will follow the IEEE code of Ethics along with our own
moral standards. Our project process and our final product will adhere to the
following relevant IEEE Code of Ethics.
 Our project, Smart Shoe, is potentially enjoyed by people of all ages and
many different locations. Therefore, our product must consider the safety,
health and welfare of the public; in order to protect the users of our
product.
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;
 We will accept and seek honest criticism of our technical work in order to
improve out project, and giving credit to whoever contributed to our
project.
To seek, accept, and offer honest criticism of technical work, to
acknowledge and correct errors, and to credit properly the contributions of
others;

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6.4 Project Feasibility
Part Description Quantity Cost($)/Unit Total Cost($)
310-313 Pico
Drive
Vibration Motors 6 2.00 12.00
NDS331N N-Channel
MOSFET
6 0.105 0.63
50kΩ Resistor Resistor 6 0.13 0.78
4.7kΩ Resistor Resistor 1 0.09 0.09
27kΩ Resistor Resistor 3 0.15 0.45
PRT-00341 LiPO
Rechargeable
Battery
1 7.95 7.95
0.1μF Capacitor Capacitor 2 0.10 0.20
1μF Capacitor Capacitor 1 0.10 0.10
4.7 μF Capacitor Capacitor 2 0.20 0.40
10μF Capacitor Capacitor 1 0.20 0.20
100 μF Capacitor Electrolytic
Capacitor
4 0.30 1.20
22μH Inductor Inductor 2 0.15 0.30
MAX710 Step up/down
DC-DC Converter
2 1.10 2.20
FSR 400 Force Sensitive
Resistor
3 6.95 20.85
Arduino Pro Mini Microcontroller 1 12.50 12.50
HC-06 Bluetooth
Module
1 10.99 10.99
LTC1734L LiPO Battery
Charging Chip
1 0.50 0.50
UMT4403 BJT Transistor 1 0.50 0.50
66-1801 SPST Toggle Switch 1 0.60 0.60
A to A USB 2.0
Cable
USB Cable 1 3.14 3.14
Shoes Shoes 1 15.00 15.00
Total 90.59 $

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6.5 Future Work
 Our biggest challenge will be to make the design more modular so that it
can be placed inside any shoe. Also, implement this project into reality by
making a prototype for the shoe with all the components inside it ,and
work perfectly.
 We also intend to make the design more compact and light weight, so that
it causes minimal distraction to the user.
 Wireless Induction Charging could be added to provide a convenient way
of charging the device without having to hook up any wires to it.
 Adding an IMU (Inertial Measurement Unit ) chip to our design could
allow useful features in the domain of sports and fitness. The data from
the IMU chip could also be integrated with the data from pressure sensing
unit to provide more accurate pressure measurement. In addition, the
magnetic compass of the IMU chip could help in navigation by helping us
determine the direction that the user is facing.

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References
[1] Institute of Electrical and Electronics Engineers, Inc. “IEEE Code of Ethics”,
ieee.org [Access date: 5/10/2014]
Available: http://www.ieee.org/about/corporate/governance/p7- 8.html
[2 ] Precision Microdrives,”10mm Shaftless Vibration Motor 3,4mm Button
Type,”310-101
Available: https://www.sparkfun.com/datasheets/Robotics/310-
101_datasheet.pdf [Access date: 15/10/2014]
[3] Interlink Electronics, “FSR 400 Series Round Sensing Resistor,”FSR 400
Available:
http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Sensors/ForceFlex/2010-
10-26-DataSheet-FSR400-Layout2.pdf [Access date: 5/10/2014]
[4] Polymer Lithium Ion Battery - 850mAh
Available : https://www.sparkfun.com/products/341 [Access date:
1/11/2014]
[5] Maxim Integrated Products, “Low Voltage-Input/3.3V/5V/Adjustable-
output, Step-Up DC-DC Converter,” MAX710
Available: http://datasheets.maximintegrated.com/en/ds/MAX710-
MAX711.pdf [Access date: 23/10/2014]
[6] Charging Circuit 80mA Li-Ion Battery Charger
Available: http://cds.linear.com/docs/en/datasheet/1734lf.pdf [Access date:
28/9/2014]
[7] Texas Instruments, “2.4-GHz Bluetooth® low energy System-on-Chip,”
CC2541F256RHAR
Available: http://www.ti.com/lit/ds/symlink/cc2540. [Access date:
3/11/2014]
[8] HC Serial Bluetooth Products, “HC Serial Bluetooth Products User
Instruction Manual,” HC-06
Available: http://www.exp-tech.de/service/datasheet/HC-Serial-Bluetooth-
Products.pdf [Access date: 12/11/2014]
[9] Arduino, “Arduino Pro Mini,” Arduino Pro Mini
Available: http://arduino.cc/en/Main/ArduinoBoardProMini
[10], “NDS331N N-Channel Logic Level Enhancement Mode Field Effect
Transistor,:
http://www.xilinx.com/products/boards/ml505/datasheets/NDS331N.pdf
[Access date: 10/11/2014]

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Appendices
Schematic Circuit Diagram
Figure 18: Schematic Circuit Diagram

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Arduino Pro Mini Circuit
Figure 19 :Arduino Pro Mini Circuit

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Bluetooth Circuit
Figure 20:Bluetooth Circuit

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Attachment (A)
DISCLAIMER
This report was written by student(s) at the ( Electrical ) Engineering
Department, Faculty of Engineering, An-Najah National University. It
has not been altered or corrected, other than editorial corrections, as a
result of assessment and it may contain language as well as content
errors. The views expressed in it together with any outcomes and
recommendations are solely those of the student(s). An-Najah National
University accepts no responsibility or liability for the consequences of
this report being used for a purpose other than the purpose for which it
was commissioned.

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