User Manual for Modified Lightning McQueen Ride on Vehicle 21 April 2015

Ye Qiu, Rem Tolentino, Taeyong Shin, Brent Hornilla, Jagan Srinivasan, William Adams Clark

I-Natural Team 2 Vertically Integrated Projects

P a g e | 1

Table of Contents

CONTENTS

Special Thanks ........................................................................................................................................... 2

Section I: Project Overview and Background ................................................................................................ 3

Vertically Integrated Projects ................................................................................................................... 3

I-Natural .................................................................................................................................................... 3

Members ................................................................................................................................................... 3

Go Baby Go! .............................................................................................................................................. 3

Section II: Physiological Problems and Biomedical Solutions ....................................................................... 4

Potential Users .......................................................................................................................................... 4

Common Lower Body Disabilities in Children ........................................................................................... 4

Cerebral Palsy................................................................................................................................ 4

Muscular Dystrophy ...................................................................................................................... 4

Spina Bifida.................................................................................................................................... 4

Osteogenesis Imperfecta .............................................................................................................. 5

Core stability ................................................................................................................................. 5

Low Grip Strength ......................................................................................................................... 5

Biomedical Solutions ................................................................................................................................. 5

Section III: Step-by-Step Building Guide ....................................................................................................... 6

Safety Warnings ........................................................................................................................................ 6

Parts and Tools Needed ........................................................................................................................ 6

Tools ...................................................................................................................................................... 6

Purpose and an Overview of Modification ........................................................................................... 7

Building Steps ........................................................................................................................................... 7

Steering Wheel ...................................................................................................................................... 7

Toggle Switch ........................................................................................................................................ 8

PVC Roll Cage and Headrest .................................................................................................................. 9

Harness................................................................................................................................................ 10

Bumper ................................................................................................................................................ 11

Stop Button (for Parents Use) ............................................................................................................. 11

Circuit and Connection ........................................................................................................................ 12

Section IV: Appendix ................................................................................................................................... 14

P a g e | 2

3D Printed Parts ...................................................................................................................................... 14

Code ........................................................................................................................................................ 15

SPECIAL THANKS

To Dr. Ayanna Howard, faculty adviser for I-Natural in providing the resources and expertise needed for this

project and for valuable knowledge on the subject matter; To Brittney English for delivering and ordering various

parts needed for the vehicle; To Giancarlo for providing invaluable technical expertise and electrical engineering

background; and to Children’s Healthcare of Atlanta for providing clinician support and advice in how to develop a

ride on vehicle with a disabled child as the primary user.

P a g e | 3

SECTION I: PROJECT OVERVIEW AND BACKGROUND

VERTICALLY INTEGRATED PROJECTS

The Vertically Integrated Projects (VIP) Program unites undergraduate education and faculty research in a team-

based context. Undergraduate VIP students earn academic credits, while faculty and graduate students benefit

from the design/discovery efforts of their teams.

I-NATURAL

The purpose of I-Natural is to develop Intuitive Interfaces for Natural Human-Robot Interaction (I-Natural). The

goal is to design, build, and test interfaces that enable humans to naturally interact with robots (whether physical

or virtual) in performing activities of daily living. Combining emerging technologies in bio-sensors,

vision/perception, gesture recognition, haptics, computer intelligence and other such components can lead to the

development of systems that can enable seamless integration of the user and the robot. The goal is to replace

traditional interfaces (e.g. joystick controllers and keyboards) with devices that allow natural communication

between humans and machines.

MEMBERS

Name Class Major Role

Rem Tolentino Junior Biomedical Engineering Team Lead

Brent Hornilla Senior Computer Engineering Head of Software

Ye Qiu Junior Electrical Engineering Documentation/Software

Taeyong Shin Junior Electrical Engineering Software/Wiki

Jagan Srinivasan Junior Computer Science Hardware/Modifications

William Adams Clark Freshman Mechanical Engineering Hardware/Modificaitons

GO BABY GO!

The Go Baby Go! Program is a program first pioneered at the University of Delaware that takes ride on

vehicles such as Power Wheels cars and modifies them to be used by children with disabilities that

normally would not have access to this kind of activity. These cars provide mobility and an opportunity

for children to grow and learn without being hampered by their disabilities.

P a g e | 4

SECTION II: PHYSIOLOGICAL PROBLEMS AND BIOMEDICAL SOLUTIONS

POTENTIAL USERS

Children with lower body disabilities or musculoskeletal disabilities can benefit from the use of a

personalized ride on vehicle that can accommodate their disabilities and enable them to use a ride on

vehicle and overcome any mobility issues associated with their disability.

COMMON LOWER BODY DISABILITIES IN CHILDREN

CEREBRAL PALSY - Cerebral palsy accounts for the largest percentage of children with physical

disabilities today. It is a condition resulting from central nervous system damage often caused

by a lack of oxygen (anoxia) before, during, or after birth. There are several types (e.g., spastic,

athetoid, ataxic), each having its own distinguishing features, but mixed types in one individual

are not uncommon. Features include:

o Delay or arrest in general motor development

o Poor head control

o Poor balance

o Lack of rotation within the body axis

o Primary walking patterns

o Poor posture control, especially in sitting, standing, and walking

o Inability to bring arms forward or overhead

o Inability to bring hands together at the midline

o Inability to reach, grasp, and manipulate objects

o Inability to use arms and hands for support

o Tendency of the body to go rigid when voluntary muscle function is attempted

MUSCULAR DYSTROPHY - Although there are many types of this disease, the most common one

is characterized by slow deterioration of the voluntary muscles. Muscular dystrophy usually

occurs within the first ten years of life and is more common among boys, but there are types

that affect females as well. Falling, clumsiness in walking and climbing, and difficulty in rising

from the floor, 4 are early symptoms of the disease. There is a progressive decline in ambulation,

during which the child usually walks with the assistance of crutches and braces before being

confined to a wheelchair. As the disease progresses, it will also be more noticeably difficult for

the child to raise the arms, sit erect, and hold the head up. The individual also fatigues easily.

SPINA BIFIDA - Spina bifida is a birth defect in which the bones of the spine fail to form

completely and cover the spinal cord. Although this condition is frequently accompanied by

hydrocephalus, the surgical shunt procedure, when used, now considerably reduces the

incidence of retardation that formerly was the inevitable result of that complication. 5 Physical

disability among spina bifida children varies from slight to severe paralysis and loss of feeling in

the lower body. Incontinence is common and presents both a medical problem and a social one.

Urinary infections are a constant threat. Skin or pressure sores resulting from braces or sitting

P a g e | 5

too long are also common because of the lack of feeling in the lower body. Feeling and function

in the upper body are usually normal.

OSTEOGENESIS IMPERFECTA - A defective development of the connective tissues at the

growing age that leads to softening of bones and the affected person experiences deformed

posture. The person is usually small built with brittle bones. The cause of this condition is

unknown but there is a strong hereditary link to it. Such persons are usually active though may

require a wheelchair or crutches for mobility.

CORE STABILITY is associated with a child’s ability to stabilize one’s body. It affects the most

basic movements such as walking and even just sitting upright. Therefore, children with low core

strength lack mobility and have trouble using DC powered motor vehicles as they are unable to

sit up straight for extended periods of time. Children who lack core stability may be able to

access DC powered vehicles through the use of a harness. A harness which supports the body at

the chest and the waist will help a child maintain the correct posture while sitting in the vehicle.

However, this modification is not described in further detail because it does not require a

software component.

LOW GRIP STRENGTH - Grip strength is the amount of force with which one can squeeze an

object. This is an important ability for many everyday activities, as it affects the ability to hold

objects. In the case of driving a DC powered vehicle, a child with low grip strength may be

unable to hold the steering wheel strong enough to turn it. Therefore, another method of

steering may be required.

BIOMEDICAL SOLUTIONS

In the following section, Step By Step Building Guide, various methods and modifications are used to

cater to a potential user who has little to no mobility in the lower body and has a lack of arm strength. In

the case of lack of core stability, children who lack core stability may be able to access DC powered

vehicles through the use of a harness. A harness which supports the body at the chest and the waist will

help a child maintain the correct posture while sitting in the vehicle. In the case of low grip strength, this

problem was solved by replacing the steering wheel with a handlebar. Handlebars require less grip

strength, and overall strength, to turn. Also, it is more appealing to children who may be more familiar

with bicycles than they are with cars. Other modifications are listed in detail in the next section.

P a g e | 6

SECTION III: STEP-BY-STEP BUILDING GUIDE

SAFETY WARNINGS

1. Make sure you always have any and all modifications checked off as safe by an electrical engineer or other

electrical expert.

2. When stripping wires it is very important that you do not “over strip”. That is, when you finish you should

not have cut through any of the wires. Make sure that strip only the plastic covering. Otherwise, the wire

diameter is decreased and there is a risk of overheating.

3. Before you begin:

- Make sure batteries are plugged in and charged

- Wear safety glasses

- Wear gloves for removing plastic burrs

PARTS AND TOOLS NEEDED

Arduino Uno Arduino Power Source 2 inch push button 1 inch push button

Potentiometer Harness Servo motor

Most tools and parts were obtained from Sparkfun.com and Amazon.

CAD Connecting part

“kill” switch

H-Bridge

Breadboard

Industrial Velcro Wires

Carriage Bolts ¼ in. x 2 in (x6)

PVC Pipes o 1 in. PVC (45 in.) ¾ in. PVC (40 in.) o 1 in. PVC, 90 degree elbow (x4) ¾ in. PVC, 90 degree elbow (x2) o PVC T-snap (x3) PVC Adapter (x2)

TOOLS

Screw Driver PVC Cutter

Wire Stripper Power Drill Soldering tools

P a g e | 7

PURPOSE AND AN OVERVIEW OF MODIFICATION

This documentation is a step by step building guide for those who have bought the original toy car and want to

rebuild the car to make it easier to control while providing more safety so that it can be used for children with

motor and/or speech disabilities. There will be three main parts of modifications on the car. A newly designed T

shape steering wheel with built-in force sensor will replace the original steering wheel. This will make the starting

of the car more intuitive, also the turning action can be accomplished with less strength required. The next part is

increased safety. As the fact that children with motor disabilities cannot control their bodies as normal children.

Improvements of safety including a roll cage, harness, bumper, and parents used stop button are built on the car.

The last part is the electrical controlling part including the Arduino as central controlling unit reading feedbacks

from force sensor and parents used stop button. With the use of the Arduino and the potentiometer, the speed

control mechanism in the car can prevent sudden speed increment.

BUILDING STEPS

STEERING WHEEL

The original steering wheel will be replaced due to difficult control. Instead, a PVC build T shape steering handle

bar will be used with force sensor build in providing easier turning and start/stop control

- Pull up the steering wheel and cut the black wire to take off the steering wheel.

- Separate the two black wires to that you have individual wires

- Strip ½ in. of each wire

- Twist the strands of each individual wire to ‘tighten’ the strands to each other

- This will be connected with a blue wire and a red wire which can be found in the next step. Wires after the

connection is shown in Figure 1

- Remove 4 screws to remove ‘face plate’ from steering wheel which will not be need

- Cut off the round edge from the bottom piece, leaving only the square base as in Figure 2

- “Feed” the black wires through the square base so that they can be tucked into the steering column and

hidden from sight

- Cut 3 pieces from the ¾ in. PVC pipe and connect as Figure 3 by a T-shape connector

- Take the bottom PVC pipe from the part assembled before, and put it in the square base cut before with

an angle

- Drill through the square base as well as the PVC pipe in two directions vertically, bolt the two parts

together Figure 4-7 shows the finished parts in four directions.

- Thread the wire through the base square and the handle bar

- Take off one piece of the handle bar and drill a hole for half inch in diameter

- Feed the wire from the bottom of handlebar and out of the hole drilled in the previous step as shown in

Figure 8

- Solder the small push button to the wire

- Insert the button to the hole as shown in Figure 9

P a g e | 8

Figure 1 Figure 2 Figure 3

Figure 4 Figure 5 Figure 6 Figure 7

Figure 8 Figure 9

TOGGLE SWITCH

The toggle switch is placed on the back of the car at the bottom. It works as a “kill switch” which means only the

toggle switch is on there is power provided. However, the car will not move until the force sensor on the handlebar

is touched.

P a g e | 9

- Remove 4 screws located on car’s seat (one screw is in the back, underneath where the battery is placed)

- There are two ‘tabs’ that still attach the seat. It just takes some force to ‘pop’ off the seat from the base of

the car

- Remove warning label

- Detach the covering that runs from underneath the warning label to the steering column (this will allow

you to have access to more of the wire)

- Pull tab and remove to expose wire running from back to front of car

- There is a blue wire and a red wire under the seat.

- Cut the blue wire just above the piece of tape

- Strip ½ in. of each wire

- Twist the strands of each individual wire to ‘tighten’ the strands to each other

- Connect one blue wire to each of the screw terminals on the toggle switch as in Figure 10

- Use 1/2 in. drill bit to drill a hole as in Figure 11 into the seat (that you removed from the base of the car)

so the toggle switch can be placed through

- Insert toggle switch through hole

- Attach backing from outside of car to secure switch. The installed kill switch’s outside and inside are

shown in Figure 12-13

Figure 10 Figure 11 Figure 12 Figure 13

PVC ROLL CAGE AND HEADREST

A roll cage built by PVC pipes is used to provide support for the children’s upper body. The headrest can avoid the

children lay back and hurt the back of head.

- Cut the PVC pipes into following length:

1 in. diameter PVC: 2 pieces of 13 ¾ in., 1 piece of 11 in., 2 pieces of 2 in.

¾ in. diameter PVC: 2 pieces of 10 in., 5 pieces of 1 in.

- Assemble the pipes with PVC connectors as shown in the picture as shown in Figure 14-15

- Use the nuts and bolts to securely attach (¼ in. bolts with ¼ in. nuts)

- Use 3/8 in. Drill bit

- Use Velcro to attach kickboard to headrest as in Figure 15

P a g e | 10

Figure 14 Figure 15

HARNESS

A harness similar as the ones used for baby safe seats is used here working as safe belt.

- Drill two holes into the seat of the car (straight down on either side)

- Be careful: underneath on the left side is where the motor is located. You’ll need to keep the seat

removed for this part and make sure the hole you drill allows room for a bolt that will not interfere with

the motor

- Use scissors or razor to make small hole on the harness to allow a bolt to go through

- Place bolt through harness

- Place bolt with harness through the seat and attach with a nut as in Figure 16

- The whole picture of the harness is shown in Figure 17

Figure 16 Figure 17 Figure 18

P a g e | 11

BUMPER

In case the car runs into wall without parent’s surveillance, the bumper can reduce the collision impact to the

children sitting in the car.

- Cut down Velcro for about 12 in. (long enough to cover the front of the car)

- Cut down same length of pool noodle and split into two pieces vertically

- Attach one piece of the Velcro to the car’s front plastic bumper with the double sided tape side

- Attach the other piece of Velcro to the cutted pool noodle also with the double sided tape side

- Stick the Velcro together, and make sure the bumper will not fall off

- Attached bumper shown in Figure 18

STOP BUTTON (FOR PARENTS USE)

While children driving the car to somewhere unsafe, parents may want to stop the car immediately. Due to the

fact that the “kill switch” is small and hard to reach, a bigger push button is installed on the back upper panel of

the car for quick access.

- Unscrew the upper panel above the headboard at the back of the car

- Take off the panel and flip it, and cut off the extra piece in the way of desired location of push button

- Polish the place cutted previously and make it a flat surface as in Figure 19

- Drill a 2 in. hole in the center for the push button to go through

- Take 2 pieces of wire, strip and attach to the button’s two connecting points

- Attach the push button in the 2 in. hole as in Figure 20

- Drill holes on the vertical back panel of the car and the panel under the headboard as shown in figure. 21-

22 for the wire to go through

- Thread the wires into the empty space under the car seat

Figure 19 Figure 20

P a g e | 12

Figure 21 Figure 22

CIRCUIT AND CONNECTION

In order to implement the control functions, the electrical part of the car need to be modified adding a set of

components controlled by the Arduino. There are two loops of circuit in the car. One circuit (Figure 23) includes

the car motor, the “kill switch” working as on/off switch, the potentiometer, and the car battery as power source.

The speed of the car can be controlled by the potentiometer by adjusting the resistance value. The potentiometer

is controlled by the servo motor in the second circuit loop.

Figure 23 Figure 24

P a g e | 13

In the second circuit (Figure 24), the most important part is the Arduino which is powered by a separate power

source. The Arduino reads in signals from the force sensor on the handlebar as well as the push button, and the

output signal goes to the servo motor which controls the potentiometer. The potentiometer is hooked up using a

3D printed part that connects the servo motor to it. When the servo motor turns, is turns the potentiometer which

causes the variable resistance needed to alter the initial speed of the vehicle.

- Place the Arduino in the empty space under the seat

- Drill a hole at the side of the car for the servo motor to put in

- Connect the components together as shown in the circuit diagram

- Put the breadboard servo motor side on the right foot side and the H-bridge on the left foot side. The

Arduino will be under the seat.

Figure 25

P a g e | 14

SECTION IV: APPENDIX

3D PRINTED PARTS

CAD Drawings for the Potentiometer to Servo Connector and Actual System Picture

P a g e | 15

CODE