Lighted Nautical Chart
In order to aid with nighttime navigation, critical nautical marks are frequently lighted. An experienced navigator can learn to read an up to date nautical chart to see which marks are lighted, and what their light color and pattern are. A chart might indicate that a certain lighthouse alternates red and white light, or that a mark flashes green once every four seconds, or even that a mark flashes Morse Code. Nautical charts also make nice artwork. I decided to make a nautical chart that that can serve as an artistic or educational piece, where lighted marks on the chart are LED's, and actually light up and flash with appropriate timing. The specific chart used here is NOAA chart 13214.
How it Works
I mounted a copy of the NOAA chart to a rigid backing, and punched holes for each of the marks to be lighted. I then inserted LED's into each hole, and set up an Arduino Pro Min to control each light from the reverse. Ideally, the chart would be powered from a wall outlet, but in the current configuration I'm using battery power. In order to extend that battery life as long as possible, processor power consumption is minimized, and the Arduino's on board regulator is bypassed. After finalizing the electronics, I mounted the chart in a custom frame.
Chart Reverse Face
The Arduino Mini does not have enough GPIO pins to control all of the LED's, so I use a series of four 8-bit shift registers (TPIC6B595). The shift registers are controlled with the Arduino's SPI interface. A 5V step-up/step-down voltage regulator ensures a consistent power supply from four AA batteries.
Breadboard PCB, with Arduino Pro Mini (top), 4 shift registers (middle), 5V regulator (bottom left), and connections to LED's (sides).