next topic »

[on:]

SOLVED

video here: https://www.youtube.com/watch?v=GvzXAXBHHrE
going to integrate it into this computer case: http://www.instructables.com/id/Laser-Cut-Mini-ITX-Case-From-Scratch/

Back in the day Be, Inc made a Be Box with two rows of leds that would give a CPU utilization level. I've been playing with my arduino and have duplicated the functionality, except now I can control four banks of LEDs using Dual shift registers (595s), 40 LEDs, and Transistors. I've got the circuit working, and arduino running any light I want (or all for that matter).

Can I make the arduino take an input from the main computer and output it onto the LEDs? How would I accomplish this?

I have a function that controls the bank, and number of LEDs to be lit, then it shifts in the next bank of data to show the next CPU utilization. Technically I can still have 2 more banks, but I don't have a 6 CPU system...

My original guess is it should listen on some serial line, for a set of numbers (bank, number of LEDs to be lit) and then output this... I'm just not sure how this is accomplished using arduino. I got it working by taking in a character on the serial port, then switching it out to the proper configuration of LEDs, I'm sure there's enough keys on the keyboard to make this work.

I used the shift PWM RGB example to propel this to glory much faster than I would have been able to on my own (about 30-60 minutes of futzing, no swearing at all)

now that I got this working on my mac (haven't gotten everything working yet), I'm going to make it work with haiku (heck, BeOS might also work)...

[Reply #1 on:]

Pretty straightforward to do. See: http://playground.arduino.cc/Main/InterfacingWithSoftware for examples of how to talk serial to the Arduino.

See http://arduino.cc/en/Tutorial/ShiftOut for how to control a row of LEDs from the Arduino.

[Reply #2 on:]

You would need an application on the PC which calculated the values for the Arduino to display and then sent them to the Arduino in a format the Arduino could understand. Since your total data set is too big to fit in a single byte you need to design a communication protocol that lets you transfer messages. By far the simplest and most robust scheme is to print out ascii text messages delimited by a newline, and parse those in the Arduino to extract the values for display. For example if you only need to transfer a fixed set of numbers, you could encode them as a sequence of comma separated values terminated by a newline.

[Reply #3 on:]

Thanks for the quick replies.

Since I'm dealing with 42 bits, I can chop it down to 20 bits, and use a bit for even and odd and that leaves me with 21 bits... the rest is just shifting it out. Depends on the size of the byte? if it's a 32 bit byte, then yes , 16 bit, then no

[Reply #4 on:]

actually, I would need 2 bits for assigning the led array (4 cpus, 0,1,2,3), and 4 bits for the 10 LEDs to light (0,1,2,3,4,5,6,7,8,9,10)

0000 CPU 1
0001 CPU 2
0010 CPU 3
0011 CPU 4

0000 No Lights
0001 1 LED
0010 2 LED
0011 3 LED
0100 4 LED
0101 5 LED
0110 6 LED
0111 7 LED
1000 8 LED
1001 9 LED
1010 10 LED

CPU 2, 8 LEDs would look something like this
00010010

so that's two octets... one 16 bit byte

Updated so they are not backwards to the uninitiated

[Reply #5 on:]

your bits are backwards. 00000001 is 1, 00000010 is 2....

If you're bad at bit math you might want to use the ShiftPWM library (http://www.elcojacobs.com/shiftpwm/)

[Reply #6 on:]

Depends on endian... big or little... My MSB is your LSB

or tomato, tomato

[Reply #7 on:]

alright, so I've modified my code for the 1 byte "packet" as listed above.

The output on the shift register looks something like this:
CPU 2, 8 LEDs (previous example, now with bits not backwards to non geeks)
Input: 1000:0010 (08:02)
Output to the data pin (clocked in after each data pin is set high for a 1, or low for a 0, then after the whole register is clocked in, it latches the data to the outputs, displaying the LEDs)
LED 1 bit: 1
LED 2 bit: 1
LED 3 bit: 1
LED 4 bit: 1
LED 5 bit: 1
LED 6 bit: 1
LED 7 bit: 1
LED 8 bit: 1
LED 9 bit: 0
LED 10 bit: 0
LED (bus 1) 11 bit: 0
LED (bus 2) 12 bit: 1
LED (bus 3) 13 bit: 0
LED (bus 4) 14 bit: 0
Blank Pin 15 bit: 0
Blank Pin 16 bit: 0

I've also added a bucket so if the 4 bits for the LED is 4 or over it just doesn't do anything.

[Reply #8 on:]

Here's what I came up with
I used the ShiftPWM library (very nice) as it allows some better control over the light levels

Code:

// Alphaseinor's Blink program
// Uses Teensyduino on a Teensy 2.0++ in it's current form
// Used to take a single character to control 40 LEDs
// These 40 LEDs are split into 4 sets of 10 LEDs
// They are controlled by 2 595 shift registers
// 4 sets of LEDs are controlled cathode to ground by NPN Transistors

// The warning from the ShiftPWM library:vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
// Clock and data pins are pins from the hardware SPI, you cannot choose them yourself if you use the hardware SPI.
// Data pin is MOSI (Uno and earlier: 11, Leonardo: ICSP 4, Mega: 51, Teensy 2.0: 2, Teensy 2.0++: 22)
// Clock pin is SCK (Uno and earlier: 13, Leonardo: ICSP 3, Mega: 52, Teensy 2.0: 1, Teensy 2.0++: 21)

// You can choose the latch pin yourself.
const int ShiftPWM_latchPin=8;

// If your LED's turn on if the pin is low, set this to true, otherwise set it to false.
const bool ShiftPWM_invertOutputs = false;

// You can enable the option below to shift the PWM phase of each shift register by 8 compared to the previous.
// This will slightly increase the interrupt load, but will prevent all PWM signals from becoming high at the same time.
// This will be a bit easier on your power supply, because the current peaks are distributed.
const bool ShiftPWM_balanceLoad = true;

#include <ShiftPWM.h>   // include ShiftPWM.h after setting the pins!

// Here you set the number of brightness levels, the update frequency and the number of shift registers.
// These values affect the load of ShiftPWM.
// Choose them wisely and use the PrintInterruptLoad() function to verify your load.
// There is a calculator on my website to estimate the load.

unsigned char maxBrightness = 50;
unsigned char pwmFrequency = 75;
int numRegisters = 2;
int numRGBleds = numRegisters*8/3;

void setup(){
  Serial.begin(9600);

  // Sets the number of 8-bit registers that are used.
  ShiftPWM.SetAmountOfRegisters(numRegisters);

  // SetPinGrouping allows flexibility in LED setup.
  // If your LED's are connected like this: RRRRGGGGBBBBRRRRGGGGBBBB, use SetPinGrouping(4).
  ShiftPWM.SetPinGrouping(4); //This is the default, but I added here to demonstrate how to use the funtion
 
  ShiftPWM.Start(pwmFrequency,maxBrightness);
}

void blink(int numberOfLeds, int cpuNumber){ //this outputs to the 595 shift registers the appropriate amount of LEDs
  //first we set which bank of LEDs we want to use
  switch(cpuNumber){ //pins 10-13 on the registers use a NPN transistor to pull the LED bus low
    case 1:
      ShiftPWM.SetOne(10,maxBrightness);
      break;
    case 2:
      ShiftPWM.SetOne(11,maxBrightness);
      break;
    case 3:
      ShiftPWM.SetOne(12,maxBrightness);
      break;
    case 4:
      ShiftPWM.SetOne(13,maxBrightness);
      break;
    default:
      break;
   
  }
  //Then we light up the number of LEDs that need to be displayed in order to make a single line graph
  for(int i=0;i<numberOfLeds;i++){ //loops the number of LEDs starting at output 1
    ShiftPWM.SetOne(i,maxBrightness); //sets 1 LED at a time in the loop
  }
}

void loop()
{   
  if (Serial.available()) { // if serial data is present
    char c = (char)Serial.read(); //note loop does not end here because it needs to switch 'c'
 
  ShiftPWM.SetAll(0); //this changes all of the sates back to off on every loop so we don't get cross talk on the different LED Banks
 
    switch (c){ // This is the switch for us to use the blink function
                // A-K for CPU 1
                // L-V for CPU 2
                // a-k for CPU 3
                // l-v for CPU 4
                // 0 turns off LEDs
                // 1-9 Sets Brightness of LEDs
      case 'A': //LED Row 1, No LEDs Showing
        break;
      case 'B': //LED Row 1, 1 LEDs Showiing
        blink(1, 1);
        break;
      case 'C': //LED Row 1, 2 LEDs Showing
        blink(2, 1);
        break;
      case 'D': //LED Row 1, 3 LEDs Showing
        blink(3, 1);
        break;
      case 'E': //LED Row 1, 4 LEDs Showing
        blink(4, 1);
        break;
      case 'F': //LED Row 1, 5 LEDs Showing
        blink(5, 1);
        break;
      case 'G': //LED Row 1, 6 LEDs Showing
        blink(6, 1);
        break;
      case 'H': //LED Row 1, 7 LEDs Showing
        blink(7, 1);
        break;
      case 'I': //LED Row 1, 8 LEDs Showing
        blink(8, 1);
        break;
      case 'J': //LED Row 1, 9 LEDs Showing
        blink(9, 1);
        break;
      case 'K': //LED Row 1, 10 LEDs Showing
        blink(10, 1);
        break;
      case 'L': //LED Row 2, No LEDs Showing
        break;
      case 'M': //LED Row 2, 1 LEDs Showiing
        blink(1, 2);
        break;
      case 'N': //LED Row 2, 2 LEDs Showing
        blink(2, 2);
        break;
      case 'O': //LED Row 2, 3 LEDs Showing
        blink(3, 2);
        break;
      case 'P': //LED Row 2, 4 LEDs Showing
        blink(4, 2);
        break;
      case 'Q': //LED Row 2, 5 LEDs Showing
        blink(5, 2);
        break;
      case 'R': //LED Row 2, 6 LEDs Showing
        blink(6, 2);
        break;
      case 'S': //LED Row 2, 7 LEDs Showing
        blink(7, 2);
        break;
      case 'T': //LED Row 2, 8 LEDs Showing
        blink(8, 2);
        break;
      case 'U': //LED Row 2, 9 LEDs Showing
        blink(9, 2);
        break;
      case 'V': //LED Row 2, 10 LEDs Showing
        blink(10, 2);
        break;
      case 'a': //LED Row 3, No LEDs Showing
        break;
      case 'b': //LED Row 3, 1 LEDs Showiing
        blink(1, 3);
        break;
      case 'c': //LED Row 3, 2 LEDs Showing
        blink(2, 3);
        break;
      case 'd': //LED Row 3, 3 LEDs Showing
        blink(3, 3);
        break;
      case 'e': //LED Row 3, 4 LEDs Showing
        blink(4, 3);
        break;
      case 'f': //LED Row 3, 5 LEDs Showing
        blink(5, 3);
        break;
      case 'g': //LED Row 3, 6 LEDs Showing
        blink(6, 3);
        break;
      case 'h': //LED Row 3, 7 LEDs Showing
        blink(7, 3);
        break;
      case 'i': //LED Row 3, 8 LEDs Showing
        blink(8, 3);
        break;
      case 'j': //LED Row 3, 9 LEDs Showing
        blink(9, 3);
        break;
      case 'k': //LED Row 3, 10 LEDs Showing
        blink(10, 3);
        break;
      case 'l': //LED Row 4, No LEDs Showing
        break;
      case 'm': //LED Row 4, 1 LEDs Showiing
        blink(1, 4);
        break;
      case 'n': //LED Row 4, 2 LEDs Showing
        blink(2, 4);
        break;
      case 'o': //LED Row 4, 3 LEDs Showing
        blink(3, 4);
        break;
      case 'p': //LED Row 4, 4 LEDs Showing
        blink(4, 4);
        break;
      case 'q': //LED Row 4, 5 LEDs Showing
        blink(5, 4);
        break;
      case 'r': //LED Row 4, 6 LEDs Showing
        blink(6, 4);
        break;
      case 's': //LED Row 4, 7 LEDs Showing
        blink(7, 4);
        break;
      case 't': //LED Row 4, 8 LEDs Showing
        blink(8, 4);
        break;
      case 'u': //LED Row 4, 9 LEDs Showing
        blink(9, 4);
        break;
      case 'v': //LED Row 4, 10 LEDs Showing
        blink(10, 4);
        break;
      case '0':
        maxBrightness = 0;
        break;
      case '1':
        maxBrightness = 25;
        break;
      case '2':
        maxBrightness = 50;
        break;
      case '3':
        maxBrightness = 75;
        break;
      case '4':
        maxBrightness = 100;
        break;
      case '5':
        maxBrightness = 125;
        break;
      case '6':
        maxBrightness = 150;
        break;
      case '7':
        maxBrightness = 175;
        break;
      case '8':
        maxBrightness = 200;
        break;
      case '9':
        maxBrightness = 225;
        break;
      default:
        break;
    } 
  }
}

Now on to programming that arduino driver for www.Haiku-OS.org haven't even seen if someone else has done it for me.

[Reply #9 on:]

Added a demo code to when the device starts up, just a random number generator... it's in the bottom else in main

video here: https://www.youtube.com/watch?v=GvzXAXBHHrE
going to integrate it into this computer case: http://www.instructables.com/id/Laser-Cut-Mini-ITX-Case-From-Scratch/

Code:

// Alphaseinor's Blink program
// Uses Teensyduino on a Teensy 2.0++ in it's current form
// Used to take a single character to control 40 LEDs
// These 40 LEDs are split into 4 sets of 10 LEDs
// They are controlled by 2 595 shift registers
// 4 sets of LEDs are controlled cathode to ground by NPN Transistors

// The warning from the ShiftPWM library:vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
// Clock and data pins are pins from the hardware SPI, you cannot choose them yourself if you use the hardware SPI.
// Data pin is MOSI (Uno and earlier: 11, Leonardo: ICSP 4, Mega: 51, Teensy 2.0: 2, Teensy 2.0++: 22)
// Clock pin is SCK (Uno and earlier: 13, Leonardo: ICSP 3, Mega: 52, Teensy 2.0: 1, Teensy 2.0++: 21)

// You can choose the latch pin yourself.
const int ShiftPWM_latchPin=8;

// If your LED's turn on if the pin is low, set this to true, otherwise set it to false.
const bool ShiftPWM_invertOutputs = false;

// You can enable the option below to shift the PWM phase of each shift register by 8 compared to the previous.
// This will slightly increase the interrupt load, but will prevent all PWM signals from becoming high at the same time.
// This will be a bit easier on your power supply, because the current peaks are distributed.
const bool ShiftPWM_balanceLoad = true;

#include <ShiftPWM.h>   // include ShiftPWM.h after setting the pins!

// Here you set the number of brightness levels, the update frequency and the number of shift registers.
// These values affect the load of ShiftPWM.
// Choose them wisely and use the PrintInterruptLoad() function to verify your load.
// There is a calculator on my website to estimate the load.

unsigned char maxBrightness = 50;
unsigned char pwmFrequency = 75;
int numRegisters = 2;
int numCPUs = 4;
int numLeds = 10;

void setup(){
  Serial.begin(9600);

  // Sets the number of 8-bit registers that are used.
  ShiftPWM.SetAmountOfRegisters(numRegisters);

  // SetPinGrouping allows flexibility in LED setup.
  // If your LED's are connected like this: RRRRGGGGBBBBRRRRGGGGBBBB, use SetPinGrouping(4).
  ShiftPWM.SetPinGrouping(4); //This is the default, but I added here to demonstrate how to use the funtion
 
  ShiftPWM.Start(pwmFrequency,maxBrightness);
}

void blink(int numberOfLeds, int cpuNumber){ //this outputs to the 595 shift registers the appropriate amount of LEDs
  //first we set which bank of LEDs we want to use
  switch(cpuNumber){ //pins 10-13 on the registers use a NPN transistor to pull the LED bus low
    case 1:
      ShiftPWM.SetOne(10,maxBrightness);
      break;
    case 2:
      ShiftPWM.SetOne(11,maxBrightness);
      break;
    case 3:
      ShiftPWM.SetOne(12,maxBrightness);
      break;
    case 4:
      ShiftPWM.SetOne(13,maxBrightness);
      break;
    default:
      break;
   
  }
 
  //Then we light up the number of LEDs that need to be displayed in order to make a single line graph
  for(int i=0;i<numberOfLeds;i++){ //loops the number of LEDs starting at output 1
    ShiftPWM.SetOne(i,maxBrightness); //sets 1 LED at a time in the loop
  }
}

void loop()
{   
  if (Serial.available()) { // if serial data is present
    char c = (char)Serial.read(); //note loop does not end here because it needs to switch 'c'
 
  ShiftPWM.SetAll(0); //this changes all of the sates back to off on every loop so we don't get cross talk on the different LED Banks
 
    switch (c){ // This is the switch for us to use the blink function
                // A-K for CPU 1
                // L-V for CPU 2
                // a-k for CPU 3
                // l-v for CPU 4
                // 0 turns off LEDs
                // 1-9 Sets Brightness of LEDs
      case 'A': //LED Row 1, No LEDs Showing
        break;
      case 'B': //LED Row 1, 1 LEDs Showiing
        blink(1, 1);
        break;
      case 'C': //LED Row 1, 2 LEDs Showing
        blink(2, 1);
        break;
      case 'D': //LED Row 1, 3 LEDs Showing
        blink(3, 1);
        break;
      case 'E': //LED Row 1, 4 LEDs Showing
        blink(4, 1);
        break;
      case 'F': //LED Row 1, 5 LEDs Showing
        blink(5, 1);
        break;
      case 'G': //LED Row 1, 6 LEDs Showing
        blink(6, 1);
        break;
      case 'H': //LED Row 1, 7 LEDs Showing
        blink(7, 1);
        break;
      case 'I': //LED Row 1, 8 LEDs Showing
        blink(8, 1);
        break;
      case 'J': //LED Row 1, 9 LEDs Showing
        blink(9, 1);
        break;
      case 'K': //LED Row 1, 10 LEDs Showing
        blink(10, 1);
        break;
      case 'L': //LED Row 2, No LEDs Showing
        break;
      case 'M': //LED Row 2, 1 LEDs Showiing
        blink(1, 2);
        break;
      case 'N': //LED Row 2, 2 LEDs Showing
        blink(2, 2);
        break;
      case 'O': //LED Row 2, 3 LEDs Showing
        blink(3, 2);
        break;
      case 'P': //LED Row 2, 4 LEDs Showing
        blink(4, 2);
        break;
      case 'Q': //LED Row 2, 5 LEDs Showing
        blink(5, 2);
        break;
      case 'R': //LED Row 2, 6 LEDs Showing
        blink(6, 2);
        break;
      case 'S': //LED Row 2, 7 LEDs Showing
        blink(7, 2);
        break;
      case 'T': //LED Row 2, 8 LEDs Showing
        blink(8, 2);
        break;
      case 'U': //LED Row 2, 9 LEDs Showing
        blink(9, 2);
        break;
      case 'V': //LED Row 2, 10 LEDs Showing
        blink(10, 2);
        break;
      case 'a': //LED Row 3, No LEDs Showing
        break;
      case 'b': //LED Row 3, 1 LEDs Showiing
        blink(1, 3);
        break;
      case 'c': //LED Row 3, 2 LEDs Showing
        blink(2, 3);
        break;
      case 'd': //LED Row 3, 3 LEDs Showing
        blink(3, 3);
        break;
      case 'e': //LED Row 3, 4 LEDs Showing
        blink(4, 3);
        break;
      case 'f': //LED Row 3, 5 LEDs Showing
        blink(5, 3);
        break;
      case 'g': //LED Row 3, 6 LEDs Showing
        blink(6, 3);
        break;
      case 'h': //LED Row 3, 7 LEDs Showing
        blink(7, 3);
        break;
      case 'i': //LED Row 3, 8 LEDs Showing
        blink(8, 3);
        break;
      case 'j': //LED Row 3, 9 LEDs Showing
        blink(9, 3);
        break;
      case 'k': //LED Row 3, 10 LEDs Showing
        blink(10, 3);
        break;
      case 'l': //LED Row 4, No LEDs Showing
        break;
      case 'm': //LED Row 4, 1 LEDs Showiing
        blink(1, 4);
        break;
      case 'n': //LED Row 4, 2 LEDs Showing
        blink(2, 4);
        break;
      case 'o': //LED Row 4, 3 LEDs Showing
        blink(3, 4);
        break;
      case 'p': //LED Row 4, 4 LEDs Showing
        blink(4, 4);
        break;
      case 'q': //LED Row 4, 5 LEDs Showing
        blink(5, 4);
        break;
      case 'r': //LED Row 4, 6 LEDs Showing
        blink(6, 4);
        break;
      case 's': //LED Row 4, 7 LEDs Showing
        blink(7, 4);
        break;
      case 't': //LED Row 4, 8 LEDs Showing
        blink(8, 4);
        break;
      case 'u': //LED Row 4, 9 LEDs Showing
        blink(9, 4);
        break;
      case 'v': //LED Row 4, 10 LEDs Showing
        blink(10, 4);
        break;
      case '0':
        maxBrightness = 0;
        break;
      case '1':
        maxBrightness = 25;
        break;
      case '2':
        maxBrightness = 50;
        break;
      case '3':
        maxBrightness = 75;
        break;
      case '4':
        maxBrightness = 100;
        break;
      case '5':
        maxBrightness = 125;
        break;
      case '6':
        maxBrightness = 150;
        break;
      case '7':
        maxBrightness = 175;
        break;
      case '8':
        maxBrightness = 200;
        break;
      case '9':
        maxBrightness = 225;
        break;
      default:
        break;
    } 
  }
  else
  {
    //startup routine
    for(int cpu=1;cpu<numCPUs+1;cpu++){
      for(int led=0;led<numLeds+1;led++){
        if (Serial.available()){break;}
        blink(random(led),cpu);
        delay(10);
        ShiftPWM.SetAll(0);
      }
    }
  }
}

[Reply #10 on:]

changed the code to have the 10 anodes loop last, and the 4 cathodes loop first... this reduces the CPU flicker on the leds.
drop the delay to 4 and the flicker goes away completely.

still working on the haiku driver... i'll post it here when I'm done.

Code:

// Alphaseinor's Blink program
// Uses Teensyduino on a Teensy 2.0++ in it's current form
// Used to take a single character to control 40 LEDs
// These 40 LEDs are split into 4 sets of 10 LEDs
// They are controlled by 2 595 shift registers
// 4 sets of LEDs are controlled cathode to ground by NPN Transistors

// The warning from the ShiftPWM library:vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
// Clock and data pins are pins from the hardware SPI, you cannot choose them yourself if you use the hardware SPI.
// Data pin is MOSI (Uno and earlier: 11, Leonardo: ICSP 4, Mega: 51, Teensy 2.0: 2, Teensy 2.0++: 22)
// Clock pin is SCK (Uno and earlier: 13, Leonardo: ICSP 3, Mega: 52, Teensy 2.0: 1, Teensy 2.0++: 21)

// You can choose the latch pin yourself.
const int ShiftPWM_latchPin=8;

// If your LED's turn on if the pin is low, set this to true, otherwise set it to false.
const bool ShiftPWM_invertOutputs = false;

// You can enable the option below to shift the PWM phase of each shift register by 8 compared to the previous.
// This will slightly increase the interrupt load, but will prevent all PWM signals from becoming high at the same time.
// This will be a bit easier on your power supply, because the current peaks are distributed.
const bool ShiftPWM_balanceLoad = true;

#include <ShiftPWM.h>   // include ShiftPWM.h after setting the pins!

// Here you set the number of brightness levels, the update frequency and the number of shift registers.
// These values affect the load of ShiftPWM.
// Choose them wisely and use the PrintInterruptLoad() function to verify your load.
// There is a calculator on my website to estimate the load.

unsigned char maxBrightness = 255;
unsigned char pwmFrequency = 75;
int numRegisters = 2;
int numCPUs = 4;
int numLeds = 10;

void setup(){
  Serial.begin(9600);

  // Sets the number of 8-bit registers that are used.
  ShiftPWM.SetAmountOfRegisters(numRegisters);

  // SetPinGrouping allows flexibility in LED setup.
  // If your LED's are connected like this: RRRRGGGGBBBBRRRRGGGGBBBB, use SetPinGrouping(4).
  ShiftPWM.SetPinGrouping(4); //This is the default, but I added here to demonstrate how to use the funtion
 
  ShiftPWM.Start(pwmFrequency,maxBrightness);
}

void blink(int numberOfLeds, int cpuNumber){ //this outputs to the 595 shift registers the appropriate amount of LEDs
  //first we set which bank of LEDs we want to use
  switch(cpuNumber){ //pins 10-13 on the registers use a NPN transistor to pull the LED bus low
    case 1:
      ShiftPWM.SetOne(10,maxBrightness);
      break;
    case 2:
      ShiftPWM.SetOne(11,maxBrightness);
      break;
    case 3:
      ShiftPWM.SetOne(12,maxBrightness);
      break;
    case 4:
      ShiftPWM.SetOne(13,maxBrightness);
      break;
    default:
      break;
   
  }
 
  //Then we light up the number of LEDs that need to be displayed in order to make a single line graph
  for(int i=0;i<numberOfLeds;i++){ //loops the number of LEDs starting at output 1
    ShiftPWM.SetOne(i,maxBrightness); //sets 1 LED at a time in the loop
  }
}

void loop()
{   
  if (Serial.available()) { // if serial data is present
    char c = (char)Serial.read(); //note loop does not end here because it needs to switch 'c'
 
  ShiftPWM.SetAll(0); //this changes all of the sates back to off on every loop so we don't get cross talk on the different LED Banks
 
    switch (c){ // This is the switch for us to use the blink function
                // A-K for CPU 1
                // L-V for CPU 2
                // a-k for CPU 3
                // l-v for CPU 4
                // 0 turns off LEDs
                // 1-9 Sets Brightness of LEDs
      case 'A': //LED Row 1, No LEDs Showing
        break;
      case 'B': //LED Row 1, 1 LEDs Showiing
        blink(1, 1);
        break;
      case 'C': //LED Row 1, 2 LEDs Showing
        blink(2, 1);
        break;
      case 'D': //LED Row 1, 3 LEDs Showing
        blink(3, 1);
        break;
      case 'E': //LED Row 1, 4 LEDs Showing
        blink(4, 1);
        break;
      case 'F': //LED Row 1, 5 LEDs Showing
        blink(5, 1);
        break;
      case 'G': //LED Row 1, 6 LEDs Showing
        blink(6, 1);
        break;
      case 'H': //LED Row 1, 7 LEDs Showing
        blink(7, 1);
        break;
      case 'I': //LED Row 1, 8 LEDs Showing
        blink(8, 1);
        break;
      case 'J': //LED Row 1, 9 LEDs Showing
        blink(9, 1);
        break;
      case 'K': //LED Row 1, 10 LEDs Showing
        blink(10, 1);
        break;
      case 'L': //LED Row 2, No LEDs Showing
        break;
      case 'M': //LED Row 2, 1 LEDs Showiing
        blink(1, 2);
        break;
      case 'N': //LED Row 2, 2 LEDs Showing
        blink(2, 2);
        break;
      case 'O': //LED Row 2, 3 LEDs Showing
        blink(3, 2);
        break;
      case 'P': //LED Row 2, 4 LEDs Showing
        blink(4, 2);
        break;
      case 'Q': //LED Row 2, 5 LEDs Showing
        blink(5, 2);
        break;
      case 'R': //LED Row 2, 6 LEDs Showing
        blink(6, 2);
        break;
      case 'S': //LED Row 2, 7 LEDs Showing
        blink(7, 2);
        break;
      case 'T': //LED Row 2, 8 LEDs Showing
        blink(8, 2);
        break;
      case 'U': //LED Row 2, 9 LEDs Showing
        blink(9, 2);
        break;
      case 'V': //LED Row 2, 10 LEDs Showing
        blink(10, 2);
        break;
      case 'a': //LED Row 3, No LEDs Showing
        break;
      case 'b': //LED Row 3, 1 LEDs Showiing
        blink(1, 3);
        break;
      case 'c': //LED Row 3, 2 LEDs Showing
        blink(2, 3);
        break;
      case 'd': //LED Row 3, 3 LEDs Showing
        blink(3, 3);
        break;
      case 'e': //LED Row 3, 4 LEDs Showing
        blink(4, 3);
        break;
      case 'f': //LED Row 3, 5 LEDs Showing
        blink(5, 3);
        break;
      case 'g': //LED Row 3, 6 LEDs Showing
        blink(6, 3);
        break;
      case 'h': //LED Row 3, 7 LEDs Showing
        blink(7, 3);
        break;
      case 'i': //LED Row 3, 8 LEDs Showing
        blink(8, 3);
        break;
      case 'j': //LED Row 3, 9 LEDs Showing
        blink(9, 3);
        break;
      case 'k': //LED Row 3, 10 LEDs Showing
        blink(10, 3);
        break;
      case 'l': //LED Row 4, No LEDs Showing
        break;
      case 'm': //LED Row 4, 1 LEDs Showiing
        blink(1, 4);
        break;
      case 'n': //LED Row 4, 2 LEDs Showing
        blink(2, 4);
        break;
      case 'o': //LED Row 4, 3 LEDs Showing
        blink(3, 4);
        break;
      case 'p': //LED Row 4, 4 LEDs Showing
        blink(4, 4);
        break;
      case 'q': //LED Row 4, 5 LEDs Showing
        blink(5, 4);
        break;
      case 'r': //LED Row 4, 6 LEDs Showing
        blink(6, 4);
        break;
      case 's': //LED Row 4, 7 LEDs Showing
        blink(7, 4);
        break;
      case 't': //LED Row 4, 8 LEDs Showing
        blink(8, 4);
        break;
      case 'u': //LED Row 4, 9 LEDs Showing
        blink(9, 4);
        break;
      case 'v': //LED Row 4, 10 LEDs Showing
        blink(10, 4);
        break;
      case '0':
        maxBrightness = 0;
        break;
      case '1':
        maxBrightness = 25;
        break;
      case '2':
        maxBrightness = 50;
        break;
      case '3':
        maxBrightness = 75;
        break;
      case '4':
        maxBrightness = 100;
        break;
      case '5':
        maxBrightness = 125;
        break;
      case '6':
        maxBrightness = 150;
        break;
      case '7':
        maxBrightness = 175;
        break;
      case '8':
        maxBrightness = 200;
        break;
      case '9':
        maxBrightness = 225;
        break;
      default:
        break;
    } 
  }
  else
  {
    //startup routine
    for(int led=1;led<numLeds+1;led++){
      for(int cpu=0;cpu<numCPUs+1;cpu++){
        if (Serial.available()){break;}
        blink(random(led),cpu);
        delay(5);
        ShiftPWM.SetAll(0);
      }
    }
  }
}