creating a more intuitive, affordable and safe navigation device
Team members: Audrey Haque - Anahide Nahhal
Master in Design Engineering @Harvard
The world today is becoming more complex, and the devices are becoming more inclusive of different features at the expense of a higher price. Your smartphone can technically do everything you want a machine to do. But by having all those features grouped within one interface, a compromise is made on some aspects to fit a maximum of function.
navigation is distracting
Typical mobile navigation assistance relies too much on visual and auditory cues often distracting bikers and pedestrians from safely and efficiently getting from point A to point B.
Felix Richter, (2014), Watch Out for Smartphone Users [ONLINE]. Available at: [Accessed 2 November 2018].
Wolfe, E. S., Arabian, S. S., Breeze, J. L., & Salzler, M. J. (2016). Distracted Biking: An Observational Study. Journal of trauma nursing : the official journal of the Society of Trauma Nurses, 23(2), 65-70.
of 18-24 years old reported being bumped into by someone who was looking down at their phone
of bicyclists were distracted (auditory or visual) at high traffic Boston intersection
navigation is the most complex part of the process
A first essential step in the design process was to understand our user and try to empathize with the pain points of his journey. We conducted interviews with bikers and observed the actions they undertake from the moment they look for the bike until they arrive. We noticed that the navigation part of the journey was the one where the user faces the most problems and we have decided to focus mostly on the pain points highlighted below.
Tactus is a haptic navigation device with an intuitive and simple communication language.
When biking, the user wears these electronic gloves before starting the ride and the gloves will vibrate to indicate directions and allow for a smooth navigation.
We decided to design specifically for the one purpose of making it as instinctive as it can get. In order to achieve this goal, we studied in depth the optimal area of intervention, and created a very intuitive haptic communication language.
For the intuitive language, we studied the different intersections and notifications that we would have to send to the user and tested it on a few people in order to make it as intuitive as possible. By having two gloves, the user receives simple notifications through the vibrations.
reason for using vibrations
Reaction times for touch, sound and sight
When studying the reaction times for the different sensory triggers, we noticed that vibrations stimulation have the fastest response times. This is why we decided to work with haptics.
Two point discrimination across the body
We then decided to understand the sensitivity of the body to touch in order to intervene in the right area. The two point discrimination technique consists of applying pressure on two points on a small area of skin and move them as close as possible until the patient cannot discern the two points anymore. The smaller the distance between the points, the more sensitive the skin in that area is.
understanding the hand sensitivity
After determining that the hand would be the optimal part of the body, we dived deeper in the sensitivity of the different areas of the hand looking at the receptive field size, the adaptation speed, the sensitivity to skin deformation whether high frequency or low, as well as the sensitivity to static force. The pacini endings seemed to be the most sensitive to a high frequency vibration. Further more, the large receptive field size lowered the chances of not targeting the exact location of the nerves. Overlaying this area with the part of the hand that would not be in contact with the handle of the bike (dissipating the vibration) helped us determine the optimal area of intervention.
the coded flow
Before starting to prototype, we started by mapping out the flow of the user throughout the journey using the device making distinctions between user actions and device response. This allowed us to better understand the whole process before starting to code.
We worked with arduino to build the physical prototype that consisted of a feather board with bluetooth connection, a battery, and a vibe motor. The electrical components (board and battery) are encased in a transparent vaccum formed shell (out of an initial 3d printed shape) that is sealed and allows for a charging port to enter to charge the battery. The vibe is encased in a 3d printed support. This system is entered in both gloves and can be controlled by a phone prior to departure setting the trajectory and then notifying the driver of the directions to take along the way.
1- Nudges distracted bikers/walkers to put their phones away and avoid accidents.
2- Lowers the chance of being a target of phone theft.
3- Minimizes time spent stationary in an unfamiliar area, increasing physical safety.
4- Encourages bicyclists to comply with state laws regarding the use of headphones.
5- It provides an affordable, portable alternative to more expensive navigation options.
(see supply chain diagram below)