Light Bar Above Main Screen
For this bar graph I'm currently using 12 - 2x5mm rectangular LED's (I used Red/Green LED's that have 3 leads - common cathode, 2 anodes 1 for each color). I was thinking to make a more graded display (2 levels for each LED – green then red so 24 levels) but realized that wouldn't really match the display in movie. The movie display looks like a 8 Red then 4 Green array, so I'm only using 2 leads for each LED – 8 with Red anode and 4 with Green anode (final design will use single color LED's).
I'm currently using two SN74HC595 - 8 bit serial to parallel out shift registers to control the LED's. This means that
16 bits of information (0 or 1 / on or off) are sent out (4 bits
are unused since there are only 12 LED's). A great tutorial on using these shift registers with LED's and Arduino's is at Adafuit - Arduino Lesson 4.
Light Bar Below Small Screens
The 10 bar LED below the 2 smaller screens, on the left side (from the examiners point of view).
These LED bar-graphs seem to fit, they
are come in a 20 DIL package with a 2.54mm pin spacing (they fit
perfectly on a solder-less breadboard, bridging the middle of the board). My initial idea was to use shift registers (74HC595's) for this bar-graph also but remembered a circuit I built following a tutorial a
few years ago that used a single Johnson Decade Counter (CD4017BE) to control
all 10 LED's and at that time I adapted it to work with an Attiny85
using an analog input (voltage divider made of a resistor and a 10K
thermistor – for basic temperature biofeedback). This tutorial is a good on on using the Johnson Decade Counter.
Johnson Decade Counter decreases the pins used to control the LED
array from 3 to 2 and eliminates the need for current limiting
resistors (though still likely a good idea) since it can only output
10mA per pin. Unlike the 595 shift registers used for the main
screen LED Bar the 4017 requires us to use rapid
switching for persistence of vision
– only one LED can be lit at a time.