Adafruit Smart RGB Neopixels not responding to p5.serialcontrol

Other Hardware LEDs and Multiplexing
1

Hi, I am trying to light up some LEDs and Adafruit RGB neopixels based on serial button clicks from a p5.js sketch. I have connected the p5.js to the Arduino Uno sketch through p5.serialcontrol. The LED lights light up, so I know I am getting serial input and that it is not a problem with the p5.js. I have tested the Neopixels in an Arduino Sketch that is not reliant on serial control, so I also know it is not a problem with the circuit.

I read that there can be some problems with the RGB Neopixels and serial control due to something with timing. Does anyone have any ideas?

#include <Adafruit_NeoPixel.h>
#ifdef __AVR__
#include <avr/power.h> // Required for 16 MHz Adafruit Trinket
#endif

#define PIN        2 

// How many NeoPixels are attached to the Arduino?
#define NUMPIXELS 4 // Popular NeoPixel ring size

Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

int LED1 = 8; //declares a variable for an led and defines the pin it will use
int LED2 = 9; //declares a variable for an led and defines the pin it will use
int inData;

void setup() {
  Serial.begin(9600);  //sets the serial data communication speed
    pinMode(LED1, OUTPUT); //sets pin 8 as an output pin suitable for an output pin
    pinMode(LED2, OUTPUT); //sets pin 9 as an output pin suitable for an output pin

    #if defined(__AVR_ATtiny85__) && (F_CPU == 16000000)
  clock_prescale_set(clock_div_1);
  #endif
  // END of Trinket-specific code.

  pixels.begin(); // INITIALIZE NeoPixel strip object (REQUIRED)
}

void loop() {
  if (Serial.available() > 0) { // if there's serial data available do this:
  pixels.setPixelColor(0, pixels.Color(0, 255, 0));
    pixels.setPixelColor(1, pixels.Color(0, 255, 0));
    pixels.setPixelColor(2, pixels.Color(0, 255, 0));
    pixels.setPixelColor(3, pixels.Color(0, 255, 0));
    
    pixels.show();
    inData = Serial.read();   // read the serial data and put the value into a variable called inData    
  if (inData == '1' ){ //if the value for inData is "1" then do this:
    digitalWrite(LED1,HIGH);   //send power to pin 8
 } 
 if (inData == '2' ){ //if the value for inData is "2" then do this:
    digitalWrite(LED2,HIGH);   //send power to pin 9
 }
  if (inData == '0' ){ //if the value for inData is "0" then do this:
    digitalWrite(LED1,LOW); //stop sending power to pin 8
    digitalWrite(LED2,LOW); //stop sending power to pin 9
    } 
  } else {
    pixels.setPixelColor(0, pixels.Color(255, 0, 0));
    pixels.setPixelColor(1, pixels.Color(255, 0, 0));
    pixels.setPixelColor(2, pixels.Color(255, 0, 0));
    pixels.setPixelColor(3, pixels.Color(255, 0, 0));
  }
}
2

There is nothing much you can do with code alone. The best thing you could use is the Dot Star type of LEDs. These use a protocol that unlike the Neopixels can be interrupted and so you will not have interference with receiving serial data.

3

I very much doubt that is the problem here. Your strip is only 4 pixels long, and it is only updated when a character is received, which, at the slow rate of 9600, is not very often, by microcontroller standards.

What would help is if you actually describe what is going wrong here. What steps do you follow when you see the problem? What do you see when the problem happens, and what did you expect to see?

Right now, I suspect this problem, whatever it is, is because of a simple coding error.

4

Have you verified the <CR><LF> needed to send the single character are not being converted to 13 and 10?

5

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