Blink
Overview: Blink is a jacket for bikers to signal that they are turning left or right easily and safely.
Type: Microcontroller Product
Collaborators: Grace Zhao, Stephanie Rempe, Emily Esposito, John Diorio and Alexandra Rempe
Check out the Medium article I wrote about Blink and was published on The Startup here.
The Blink Jacket prototype #2 in action
Overview
While cycling is both cost-efficient and environmentally-friendly, it is also quite dangerous. There are over 40,000 reported biking accidents every year, mostly occurring in urban areas. One of the main reasons for biking accidents is the lack of visibility between bikers and other users on the road. While cars have horns and signals to speak to other drivers, bikers are limited to hand signals. Hand signals are ineffective during periods of poor light, force cyclists to maintain control using only one hand, and many people simply neglect to use them.
Taking into account these issues, we wanted to design a jacket that has turn signals embedded in the clothing’s back panel. The turn signals will be controlled by buttons on the sleeve that ensure both hands can remain on the handlebars at all times.
With limited resources and having to socially distance halfway through the project due to COVID, the team and I had to get creative. We were up for the challenge.
Accessible materials: Arduino, light bulbs, resistors, wires, cloth (jacket), acrylic.
Accessible tools: 3D printers, laser cutter, and solder irons.
Before we got to building, some team members sketched out some preliminary designs:
Figure 1–4 : The initial concept sketches
After sketching and having a clearer vision, we were ready to start building our first prototype!
Prototype One
Goals:
The goal of prototype one was to design a functioning circuit powered by an Arduino that could turn a left signal on, a right signal on, and both signals on simultaneously
The Circuit:
To model the left turn signal, five yellow LEDs were used, and to model the right turn signal, five red LEDs were used. The LEDs were designed in parallel preventing a burnt out bulb from breaking the circuit. Each LED was connected in series to a 220 resistor, this resistance was chosen to maximize the brightness of the LED. There were two switches controlling the left turn signal, and two switches controlling the right turn signal. One switch turned the signal on and one switch turned the signal off. The ports labeled Dxare input ports on the Arduino that sent an input signal to the desired output component. All components of the circuit are connected to a common ground.
Figure 5: Circuit design executed on two breadboards controlled by an Arduino powered by a 9V battery
Figure 6: schematic of circuit design for one turning signal- identical for both sides with different input ports
We had the hardware but we needed to program it…
The Arduino Code:
The following Arduino code was used to implement the circuit in figure 5. Pin 5 controls the left turn signal (5 yellow LEDs), pin 8 controls the left ‘ON’ button, and pin 9 controls the left ‘OFF’ button. Pin 6 controls the right turn signal (5 red LEDs), pin 10 controls the right ‘ON’ button, and pin 11 controls the right ‘OFF’ button. This system is open loop as there is no feedback from the output back into the input.
Figure 7: Signaling Jacket Prototype One Arduino Code
Assembly:
The assembly of the first prototype was achieved by taping the circuit, Arduino, and battery to a large piece of cardboard. A black t-shirt was cut and used as sample fabric to represent the back of a jacket. Ten holes were cut into the fabric and each LED was fed through its corresponding hole. The fabric was then tacked onto the cardboard covering the underlying circuit components. The cardboard hexagon was laser-cut to resemble a stop sign, and the word ‘STOP’ was engraved into it.
Figure 8: Assembly of the First Prototype
Takeaways:
The first prototype was an excellent way to view the functionality of the circuit, and the way the LED signals would look. The stop sign was deemed unnecessary, as it was hard to view from far away, and added weight to the design. It was also concluded that the Arduino breadboards were not a functional way to support the LEDs as they do not adapt to human movement and would be uncomfortable for a biker to wear.
After considering the takeaways from prototype one, we were ready to get started on prototype two…
Prototype Two
Goals:
The goals of prototype two were to integrate the circuit from prototype one into a jacket, and to eliminate the use of a breadboard .
The Circuit:
The same circuit from prototype one was used in prototype two. The only difference was that the different components were soldered together to remove the use of a breadboard. Additionally, a case was 3D printed to hold the Arduino, however the measurements were slightly off and it did not fit correctly. The circuit battery was held in place using a pocket sewn into the interior of the jacket.
Figure 9: soldered circuit components attached to Arduino Uno, and powered by 9V battery
Figure 10 : 3D printed Arduino case
Assembly:
The second prototype was assembled by sewing the circuit into a rain jacket purchased from Savers. Two white arrows were laser cut with five holes of diameter 5mm in order to fit the LED leads through. The two arrows were sewn into the jacket using two holes on the top and bottom. The LED leads were fed through the jacket’s outer layer, where they were connected to the rest of the circuit. The Arduino was sewn into the center of the jackets back, along with the battery pouch (see figure 9).
The on and off buttons were sewn into each sleeve. They were connected to the Arduino by wires that ran through each of the sleeves. All the wires were held together by either tape or wire fasteners to keep them from getting tangled.
Figure 11: Signaling Jacket Prototype Two
Figure 12: On and Off buttons sewn into the sleeves of the jacket
Takeaways:
The second prototype was fundamental in understanding the way the signaling jacket interacted with the biker wearing it. The signals turned out very well, and were extremely visible in dark lighting. A major concern however, was the confusion of the user not knowing when the signals were on or off, due to the multiple button input. Another concern was the durability of the signaling jacket in wet climates where parts of the circuit may get wet. Furthermore, to reduce any possible injury, prototype two revealed that our next design iteration should encase all of the electronics so that they were not directly in contact with the biker.
After two iterations, we felt we were heading the right direction for the final prototype!
Final Prototype
Goals:
The goals of the final prototype were to control the turning signals using only one button per sleeve, to make the jacket waterproof, and to contain all of the wires and Arduino in some form of case to prevent interaction between them and the biker.
Figure 13: circuit with only one switch and additional feedback LED
The Circuit:
The circuit for the final prototype was identical to the circuit used in prototype one, except that one of the switches was eliminated. By moving to a circuit with only one switch the user does not get confused which button represents ‘ON’ and what button represents ‘OFF’. (figure 13)
A future design consideration was to also include an additional feedback LED, that was sewn into the sleeve, and turned on when the turn signal went on, and off when the turn signal went off. This would help give the biker visual feedback, and confirmation of being visible.
The Arduino Code:
In the final prototype, the Arduino code was updated to handle the functionality of one button controlling the on/off signal input to the turn signals. Two state variables: state and stateB were used to keep track of whether the left and right turn signals were on or off. A state variable set to 0 represents off while a state variable set to 1 represents on.
Figure 14: Signaling Jacket Final Prototype Arduino Code
Assembly:
In order to assemble the final prototype a new rain jacket was purchased from Savers, that was thicker and more resistant than the one used in prototype two. The circuit from prototype two was removed and an additional feedback LED was soldered into the sleeve in place of the second input button.
Figure 15 is the first iteration of a thin flexible box that would hold the Arduino, wires, and LED lights in place. The box was made of thin cardboard with a 3D printed top that featured arrows holding LED holes. Some materials for future iterations of the box included foam, acrylic, and PLA.
Figure 15: first iteration of case to enclose Arduino, wires and LED’s
Figure 15a: Engineering drawing of Figure 15 box
Figure 16a: first iteration of case to enclose Arduino, wires and LED’s
Figure 16b: Engineering drawing of Figure 15 top
Figure 15b: Engineering drawing of Figure 15 box top
The second box prototype included transparent arrows cut out of acrylic with holes to hold the LED lights (see Figure 17). The second box was also designed to reduce its total volume, so was cut into a hexagon shape, and glued together with super glue. It had holes cut out of the sides intended for the wires that attached to the sleeves (see figure 18) .
Figure 17: transparent arrows made of PVC
Figure 18: Further iterations of box prototype 2
Figure 19: Final box prototype
The final box prototype is made of white acrylic and with the clear acrylic arrows attached to the top (see Figure 19). The box is opaque so that the Arduino cannot be seen, but the arrows are transparent so that the lights can be seen. The box would be held together with super glue so that it could withstand the wear and tear that comes with biking.
Takeaways:
Before the COVID-19 interruption, this iteration was on its way to bringing all of the components together into a contained box. The box would act as a complete unit, abstracting away the Arduino and the majority of the wires. This iteration also improved the user experience by simplifying the interface. Users now only need to push a single on/off button. Before, when there were two buttons, it would have been possible for a user to push the “off” button when they meant to press “on.”
Future iterations should include a feedback LED to further improve the user interface. Other pain points with the current design could be discovered through demo testing with bike riders.
Next Steps
Marketing:
In order to finalize the jacket’s design, we created a brand name and logo. The brand name is “blink,” with a red arrow as the “l,” referencing the jacket’s blinking arrows.
Figure 20: Brand logo
Two logos were created for the jacket — both have distinct designs that represent the different styles that the jacket can come in. The first logo, displayed on the left, depicts half a bike with two arrows in the wheel referencing the back of the jacket. The second logo, displayed on the right, portrays a smiley face with bicycle wheels representing the face’s eyes and “Blink” written in a graffiti style. Both the brand name and logo depicted below were created with Adobe Illustrator.
Figure 21: Jacket Design 1 — Adobe Illustrator Figure 22: Jacket Design 2- Procreate
Conclusion
Early on, the group identified an important problem that many of us face on a daily basis: bicycle signaling and safety. The group quickly iterated through designs, constantly focusing on improving the user/jacket interface. We also discovered the importance of creating a box to protect and abstract away the circuit. These changes led to a product that we felt good about putting into the hands of demo users.
With the unexpected transition to remote learning, the group was not able to receive feedback from bicycle riders. In the future, the group would like to come back together to test the Signaling Jacket with bicycle riders, further pushing the product forward.