Sending 5 Led pixel values to arduino , is this a good way?

Question

I wanted to install a 5 LED strip underneath my PC's front panel. I want to send color over PC so it can change when i open different apps, with temperature or etc!

So all I think the best way to do this is to just use Arduino to set the LED Values!

But I have had some troubles creating a good communication protocol for this, I've been just simply sending 45 digits (15 3 digit numbers) to my Arduino with serial. here's code: Arduino :

#include "Adafruit_NeoPixel.h"
#include "WS2812_Definitions.h"

#define PIN 4
#define LED_COUNT 5

struct pixel {
  int R = 0;
  int B = 0;
  int G = 0;
};

Adafruit_NeoPixel leds = Adafruit_NeoPixel(LED_COUNT, PIN, NEO_GRB + NEO_KHZ800);

char count = 1;
int pixelNumber = 0;
struct pixel tempPixel;
//struct pixel Pixels[LED_COUNT];

void setup()
{
  Serial.begin(9600);
  Serial.println("Init");
  leds.begin();  // Call this to start up the LED strip.
  clearLEDs();   // This function, defined below, turns all LEDs off...
  leds.show();   // ...but the LEDs don't actually update until you call this.
}

void loop() {
  if(Serial.available() > 0) {
    if(count == 1) {
      tempPixel.R = PC_Receive();
    } else if (count == 2) {
      tempPixel.G = PC_Receive();
    } else if (count == 3) {
      tempPixel.B = PC_Receive();
      count = 0;

      setPixelColor(pixelNumber, tempPixel);
      Serial.println(pixelNumber);
      leds.show();
//      Pixels[pixelNumber] = tempPixel;
      if(++pixelNumber >= LED_COUNT) {
        pixelNumber = 0;
      }
    }
    count++;
  }

//  if(pixelNumber == 0) {
//    for(int i = 0; i < LED_COUNT; i++ ) {
//       setPixelColor(i, Pixels[i]); 
//    }
//    
//    leds.show();
//  }
}

void setPixelColor(int a, struct pixel P)
{
  leds.setPixelColor(a, P.R, P.G, P.B);
}

char PC_Receive() {
  int result = 0;

  while(Serial.available() == 0);
  result += ((int)Serial.read() - '0') * 100;

  while(Serial.available() == 0);
  result += ((int)Serial.read() - '0') * 10;

  while(Serial.available() == 0);
  result += ((int)Serial.read() - '0');

  Serial.println(result);
  return result;
}







void setColourRgb(unsigned int red, unsigned int green, unsigned int blue) {
  for(int i = 0; i < LED_COUNT; i++) {
    leds.setPixelColor(i, red, green, blue);
  }
  leds.show();
 }

And here's PC's dirty code in python:

import serial
import time
import random

class Pixel:

    def __init__(self, R, G, B):
        self.R = R
        self.G = G
        self.B = B

def clearAll():
    for i in range(0,5):
        ser.write("000000000")

def sendPixel(pixels):
    for i in range(0,5):
        ser.write(str(pixels[i].R).zfill(3))
        ser.write(str(pixels[i].B).zfill(3))
        ser.write(str(pixels[i].G).zfill(3))


ser = serial.Serial('/dev/ttyACM2', 9600)

little = [0,0,0,0,0]

for i in range(0,5): 
    little[i] = Pixel(0,255,50)
sendPixel(little)

time.sleep(0.5)
clearAll()

the problem is it isn't stable, i think i should just use an \n at end or send back OK or something to confirm it, but that would make it slow if i did it for each value! (and checking only once after all 5 leds are send would mean sending more values until i receive the ok and clearing and sending them again!)

Can you recommend me a better way?

Thanks!

EDIT: Just wanted to say! it's almost done! It does change color when i open chrome, and i think at 115200 baud rate it's fast enough to not notice a delay (although at 9600 i felt like it's slower then my (xxx/xxx/xxx....) protocol but it's better and works at 115200

i will add some basic functions to my python side and add a rainbow effect I will also add GPU temperature and etc... it's not going to be really hard on linux but windows, im not sure :D

Answer 1

I would recommend a similar solution as DaveX with a small modofication.

If you bitmask your LEDS, and leave room for a possible additional 3, you can mask any combination of them in the space of 00-FF. then you could send to the arduino a single string of 0xFFFFFFFF FF(LED bitmask),FF(Red value), FF(Green Value), FF(Blue Value).

so LED 1 {00000001 =01} all red {FF0000} would be 0x01FF0000

LED 2 and 4 {00001010 =0A} all green {00FF00} would be 0x0A00FF00

LED 5 and 1 {00010001 =11} all blue {0000FF} would be 0x110000FF

ALL LEDS off would be 0xFF000000

All LEDS onn full white would be 0xFFFFFFFF

Answer 2

I'd recommend adding digits to a digit register, setting the an R,B,G register with R,B,G and setting values of led a-e to the RBG registers when you get an a-e, ignoring whitespace, and clearing the register otherwise. So:

 ser.write("xRBGabcde\n")  # clear all the LEDs
 ser.write("x127RBb")       # make led b half-purple, relying on prior state 
 ser.write("x255Gc")        # make led c greenish-white