Inspiration
There is a professor researching LiFi applications in V2V communications here at UM Dearborn. After learning about his work, we thought that this event would be a good opportunity to learn more about what goes into the technology.
What does it do
Our project is a simplex demo of what LiFi implementation could look like in automotive applications. The idea is that typical short range ad-hoc communication mediums are highly prone to sources of interference like EMI and ground clutter, both of which are prevalent in automotives. Light, however, is very resistant to typical sources of both EMI and the sort of ground clutter that would cause problems with shortwave radio in a car. In our demo we translate a packet of data into a physical signal by flashing an LED and receiving it on the other end through a photoresistor.
How we built it
The hardware we used were two Arduino 101 boards with Grove series shields, a Grove LED controller, and a Grove light sensor. Our, embedded software was built using the Arduino IDE in C++, and our UI/UX software was built using C#. We build the packets client-side and send them over a USB port to the transceiver, which is the first Arduino, with the attached LED socket. When the LED is off, the receiver interprets a logical 0, and when the LED is on, the receiver interprets a logical 1.
Challenges we ran into
Our biggest challenge was probably hardware limitations. The LED simply doesn't have enough intensity for the photoresistor to detect a signal from a significant distance, and not in ambient lighting conditions. Additionally, while it is not a problem for this demo, since it was intentionally slowed down such that a human could visualize the packet as it is being sent, the photoresistor requires about 30 ms to update, which for a real communications network would likely result in insufficient communication speeds.
Accomplishments that we're proud of
We were very excited that we could implement this protocol, even in a small way in such a short period of time.
What we learned
This demo taught us a lot about the physical layer of optical communication. Particular, we learned about hardware limitations, and the challenges faced by more serious researchers developing this technology.
What's next for LiFi
In this demo we demonstrated a potential vehicle safety application that would allow an AEB to be applied if a human's reaction speed was insufficient to avoid a rear-end collision with another vehicle, but the infrastructure allows for any number of unique signals to be communicated across short-range networks. One stand out application far into the future, is that this signaling could enable self-driving vehicles to communicate data between each other to allow for better predictive decision making.
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