Accomplishments this week:
- Designed signal light patterns. Since at full capacity, the LED strip can consume 12 – 15 A at 5V, we need to be careful about turning on all of the light s at the same time. Therefore, I designed some light patterns that try to be conservative on the number of LEDs used.
Above: brake light is the entire panel, but at low power
Below: Turn signals, we are not using all the lights.
- Listened to other presentations, and received feedback from Prof. Ken about what steps to take in the future, which include batteries and weight specs.
- Received LED matrices, wrote code to interface with the matrix.
- Drawing diagrams and helping write the design review paper.
Concerns:
- The LED matrix code is not hard to write in terms of turning 2D data[][] into 1D serial data to be interpreted by the Arduino, but the problem is that if we want to store signals that are very specific, a single 16×16 bit-vector to describe a signal is very expensive, if we have around 100 such signals. This is made worse, since the Arduino Nano also has a very limited memory. One possible solution we may have to consider, is to offload the signal memory to the Pi, and then have the Pi send over communication the signal that the Nano should be displaying. This can be cached, for better performance, so we don’t have to fetch 256 bits every time we want to display a signal.
- We are bit worried about how much battery power we need. We are currently thinking about one on the bike and one on the jacket, the Pi and the LED matrix are the two biggest energy suckers.