The document summarizes a project to create a jacket for cyclists that uses LED lights along the arms to signal turns. A group of 3 students followed steps to 1) choose the project, 2) design the jacket with LEDs along the arms, and 3) develop a prototype using an Arduino, flex sensors, and conductive thread. Each member participated in design, component selection, coding, and implementation. The programmable circuit uses flex sensors and LEDs along each arm to signal turns. Known issues include the flex sensors behaving digitally through threads and sensitivity to direct arm contact.

1. Creative Interactive Objects - Report
Project: Cyclist’s Jacket
Group: Marzena (120328206), Mateus (130614737) and Vanessa (130614531)
1. To reach the solution we presented, we followed these steps:
1. Project choice - After a discussion about which project option should we choose and
each one of us found more interesting, challenging and practical, we decided to pick the
cyclist’s jacket. The fact that we are more familiar to cyclists giving indications about
their turning directions in the streets than to the other projects also impacted on our
choice.
2. Design of the product - The next step was to design how the jacket would function and
look like. This phase was crucial to come up with a design that would make the
interaction between the clothing and the cyclist, which is our target user, the most
natural, comfortable and engaging as possible. However, we also had to take into
account that the components we had available to turn the design model into a functional
prototype might have take some time to arrive.
We chose to put the LEDs along the sides of the arms on the jacket, so the light would
be visible even if the cyclist is using a backpack. Also for this reason, we decided not to
put any LEDs on the back. Furthermore, we decided to put the Lilypad inside on the
back, so it would be protected against possible bad weather, increasing the durability of
the product. We also looked forward to make the LEDs blink in the same speed of car
lights when they are turning, so all the actors involved in the scenario (cyclists, drivers,
pedestrians) would be more familiar with the signal.
3. Prototype development - Firstly we made a low-fi prototypes on paper sheets so we
would know how and where exactly the conductive thread goes and where the sensors
and LEDs should be to give us the best results. Secondly, we designed the circuit with
Arduino Uno and breadboards. As the components started arriving, we started to build
the working prototype. We firstly made tests with isolated components in the Arduino
Uno Board to understand how they work, and then we incrementally integrated them
with the jacket.
2. The major tasks undertaken were:
● Designing the product
● Choosing components
● Coding
● Implementation of the circuit in the prototype
The two first tasks took one day each. The coding started as the components were

2. delivered. The implementation of the circuit, though, had to wait for the delivery of the majority
of the components, which caused a massive impact in the planned schedule (explained on next
topics).
The next topic explains with more details the distribution of the tasks among the group
members.
3. Responsibilities of each member:
● Marzena - Participated actively in the following activities: design of the jacket, design of
the circuit, coding, daily check with Dave about delivery of components, implementation
of real circuit in jacket, research about conductive thread and its usage with Lilypad,
sewing the circuit into the jacket, prototyping.
● Mateus - Participated actively in the following activities: design of the jacket, design of
the circuit, coding, daily check with Dave about delivery of components, implementation
of real circuit in jacket and troubleshooting problems in the circuit.
● Vanessa - Participated actively in the following activities: planning design of the jacket,
design of the circuit and coding, daily check about delivery of components, research
about Lilypad connections and common circuits, implementation of the real circuit and
debugging.
4. User Manual: instructions on how to operate the product and also interact with it
including information on installation and setting up.
Each circuit is pre-programmed so the only thing you need to do is to turn the battery attached
on the front on (it has a small switch on the left hand side). After doing that you will see that the
light on both Lilypad and the battery supply has turned on and the jacked is ready to use.
To turn on the side LED’s simply just raise your arm like you usually do to take a turn either right
or left and the signal lights will start blinking. To turn them off just put your arm down and
continue your ride.
After you get off the bike, please remember to turn off the battery supply with the same switch
you turned it on.
In case the battery runs out please replace it with the same one which is a LiPo 3.7 V battery.
When any problems would occur please do not hesitate to contact your supplier for help.
Video demonstrating use of jacket: http://www.youtube.com/watch?v=4uxZaYNTusg

3. 5. Programmers Guide
a. A brief discussion of the design decisions taken.
The hardware components of this project are:
● Red LEDs and one resistor of 560 Ohm for each LED used.
● Conductive Thread.
● Flex Sensors (4.5”) and one resistor of 10k Ohm for each sensor used.
● LilyPad Arduino atmega328.
The arduino used in this project is LilyPad because it is a wearable e-textile technology.
Each LilyPad was creatively designed to have large connecting pads to allow them to be sewn

4. into clothing. Various input, output, power, and sensor boards are available. And they're also
washable. Those were the main reason to choose this type of Arduino.
As a sew-board, the project connects most of the components to LilyPad through
conductive threads. Also, we choose Red LEDs because Red is a bright colour. Also, we
choose Flex Sensor because of its suitability in the functionality. As Flex Sensor is a Sensor
b. Breadboard layout sheet for your final circuit.
In the Layout is only represented the left arm. To build the right arm, the sketch is the
same. Conductive threads that carry different signals (positive and negative) can not
touch each other. Make sure you protect threads with some non-conductive material.
Video demonstrating part of the built circuit: http://www.youtube.com/watch?v=FzRcpkZ-MKw
c. Testing conducted.
First, build a simple circuit with only the LEDs. To test if the connections work, build a simple
program and check if the LEDs are blinking. If so, you can connect the flex sensor and calibrate
the signal to what you want as threshold for blinking the LEDs.
d. Code.
/*-------------------------------*/
//GLOBAL VARIABLES
//Flex Sensor Pin (flexPinLeft)
//the analog pin the Flex Sensor is connected to
int flexPinLeft = A2;
int ledLeft = 2;
int ledDelay = 200;
int flexPinRight = A0;
int ledRight = 6;
int flexThreshold = 0;
/*-------------------------------*/
//FUNCTIONS//
void setup() {
//Setting the Outputs

5. pinMode(ledLeft, OUTPUT);
pinMode(ledRight, OUTPUT);
}
void loop(){
int flexLeftValue = analogRead(flexPinLeft); // Getting value of left arm.
int flexRightValue = analogRead(flexPinRight); // Getting value of right arm.
int(50); // Delay for helping on getting analog signal.
//Check flexLeft value.
if(flexLeftValue == flexThreshold) {
blinkLeds(ledLeft); //leds on
} else {
turnOffLeds(ledLeft); //leds off
}
//Check flexRight value.
if(flexRightValue == flexThreshold) {
blinkLeds(ledRight); //leds on
} else {
turnOffLeds(ledRight); //leds off
}
}
//This function blinks LEDs given as parameter.
void blinkLeds(int led){
digitalWrite(led, HIGH);
delay(ledDelay);
turnOffLeds(led);
}
// This function turns off LEDs given by parameter.
void turnOffLeds(int led){
digitalWrite(led, LOW);
delay(ledDelay);
}
e. Known shortcomings.
It was realized that when connecting the flex sensor through conductive threads, its
behaviour was as digital input. Thats why the threshold is 0 instead of other value. This is why
the code works like that.
When in direct contact with the arm of the cyclist, the flex sensor changes its resistance
and does not work properly. One possible solution is to involve the Flex Sensor with some Non-
Conductive material.
This prototype used power through normal cable. The ideal is to use Power Supply
attached to the LilyPad.