# Code processing at slow speed

**URL:** <https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291>\
**Category:** General Guidance\
**Created:** [August 13, 2024, 4:44am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291 "2024-08-13T04:44:51Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![foreyan](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/foreyan/32/1038031_2.png) [@foreyan](https://forum.arduino.cc/u/foreyan)\
**Post date:** [August 13, 2024, 4:44am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/1 "2024-08-13T04:44:51Z")

</div>

My project is basically about displaying lightshows on a ws2812 led stick but the brightness is changing slower than expected.

Code itself is pretty simple, in brief:

1. reads a string containing 4 diff data values
2. assign them each to a variable (value1 to value4)
3. perform basic calculations (multiply, subtraction)
4. assign those variable as brightness value to each led (8 led in total)

Speed of reading data is fast, but displaying the brightness is where the slowness occurs

Anyway here's my code, any tips and guidance would be much appreciated!

For hardware specs, im using Arduino UNO R3 ATMega328P

```arduino
#include <Adafruit_NeoPixel.h>

#define NYEO 4
#define NUMPIXELS 8

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUMPIXELS, NYEO, NEO_GRB + NEO_KHZ800);

int r = 0;
int g = 255;
int b = 139;
int fr = 0;
int fg = 0;
int fb = 0;
uint32_t colors[NUMPIXELS];

int value1, value2, value3, value4;
int noko1, noko2, noko3, noko4;

void setup() {
  Serial.begin(9600);
  strip.begin();
  strip.show();
}

void loop() {
  if (Serial.available() > 0) {
    // Stage 1 Denial
    String input = Serial.readStringUntil('\n');  
    parseInput(input);
    // Stage 2 Anger
    if(value1 > 0) {noko1 = 39;}
    if(value2 > 0) {noko2 = 39;}
    if(value3 > 0) {noko3 = 39;}
    if(value4 > 0) {noko4 = 39;}
    // Stage 3 Bargaining
    if(noko1 > 0) {noko1--;} 
    if(noko2 > 0) {noko2--;} 
    if(noko3 > 0) {noko3--;} 
    if(noko4 > 0) {noko4--;} 
    // Stage 4 Depression
    int neko1 = noko1*6;
    int neko2 = noko2*6;
    int neko3 = noko3*6;
    int neko4 = noko4*6;
    int BrightNya[NUMPIXELS] = {neko1,neko1,neko2,neko2,neko3,neko3,neko4,neko4};
    for(int i = 0; i < NUMPIXELS; i++) {
      fr = (r*BrightNya[i])/255;
      fg = (g*BrightNya[i])/255;
      fb = (b*BrightNya[i])/255;
      colors[i] = strip.Color(fr,fg,fb);
    }
    // Stage 5 Acceptance
    for(int i = 0; i < NUMPIXELS; i++) {
      strip.setPixelColor(i, colors[i]);
    }
    delay(10);
    strip.show();
  }
}

void parseInput(String input) {
  int startIndex = 0;
  int commaIndex;
  int valueIndex = 0;

  while ((commaIndex = input.indexOf(',', startIndex)) != -1 && valueIndex < 3) {
    String valueString = input.substring(startIndex, commaIndex);
    int value = valueString.toInt();
    
    switch (valueIndex) {
      case 0: value1 = value; break;
      case 1: value2 = value; break;
      case 2: value3 = value; break;
    }
    startIndex = commaIndex + 1;
    valueIndex++;
  }
  
  value4 = input.substring(startIndex).toInt();
}

```

i have tried simplying and combining the calculations into one line and got rid of variable noko1 to noko4 but its still slow  
i have also tried increasing baud rate from 9600 to 115200, no effects as well

---

<div class="post-metadata">

**Author:** ![hallowed31](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/hallowed31/32/1093680_2.png) [@hallowed31](https://forum.arduino.cc/u/hallowed31)\
**Post date:** [August 13, 2024, 4:48am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/2 "2024-08-13T04:48:53Z")

</div>

> [@foreyan](#):
>
> Anyway here's my code, any tips and guidance would be much appreciated!

Have you tried the FastLED library? I haven't but lots of folks seem to prefer it to the Adafruit option.

---

<div class="post-metadata">

**Author:** ![foreyan](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/foreyan/32/1038031_2.png) [@foreyan](https://forum.arduino.cc/u/foreyan)\
**Post date:** [August 13, 2024, 4:53am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/3 "2024-08-13T04:53:57Z")

</div>

no not yet but i'll give it a shot

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<div class="post-metadata">

**Author:** ![foreyan](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/foreyan/32/1038031_2.png) [@foreyan](https://forum.arduino.cc/u/foreyan)\
**Post date:** [August 13, 2024, 5:00am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/4 "2024-08-13T05:00:00Z")

</div>

i just modified my code and used fastLED.h library and the speed is still relatively the same as using adafruit library

---

<div class="post-metadata">

**Author:** ![hallowed31](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/hallowed31/32/1093680_2.png) [@hallowed31](https://forum.arduino.cc/u/hallowed31)\
**Post date:** [August 13, 2024, 5:09am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/5 "2024-08-13T05:09:13Z")

</div>

> [@foreyan](#):
>
> Speed of reading data is fast

Seems to me that reading the Strings would be the slow part. What data are you reading into Serial and is there a way to shorten it to just chars? How long are these Strings you're

> [@foreyan](#):
>
> `String input = Serial.readStringUntil('\n'); `

?

---

<div class="post-metadata">

**Author:** ![foreyan](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/foreyan/32/1038031_2.png) [@foreyan](https://forum.arduino.cc/u/foreyan)\
**Post date:** [August 13, 2024, 5:12am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/6 "2024-08-13T05:12:27Z")

</div>

its actually just 4 integer data but separated with a comma. Here's the python code thats sending the data

```arduino
    datanya = "{},{},{},{}".format(neko1,neko2,neko3,neko4)
    ser.write((datanya + "\n").encode())

```

so the serial data sent is "0,0,0,0" with a "\n" at the end  
the values of each integer changes between 0 and 1

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<div class="post-metadata">

**Author:** ![hallowed31](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/hallowed31/32/1093680_2.png) [@hallowed31](https://forum.arduino.cc/u/hallowed31)\
**Post date:** [August 13, 2024, 5:17am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/7 "2024-08-13T05:17:07Z")

</div>

Yeah, I'm not really sure but I remembered something about the `strip.show();` function and interaction with Serial.

Take a look at this discussion, hope it helps.  
[https://forums.adafruit.com/viewtopic.php?t=134771](https://forums.adafruit.com/viewtopic.php?t=134771)

---

<div class="post-metadata">

**Author:** ![GoForSmoke](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/goforsmoke/32/1127097_2.png) [@GoForSmoke](https://forum.arduino.cc/u/GoForSmoke)\
**Post date:** [August 13, 2024, 5:20am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/8 "2024-08-13T05:20:55Z")

</div>

In loop(), you create 4 local ints with the same names as 4 global ints. I don't think you know what you're doing.

```arduino
    int neko1 = noko1*6;
    int neko2 = noko2*6;
    int neko3 = noko3*6;
    int neko4 = noko4*6;

```

right before that

```arduino
    if(value1 > 0) {noko1 = 39;}
    if(value2 > 0) {noko2 = 39;}
    if(value3 > 0) {noko3 = 39;}
    if(value4 > 0) {noko4 = 39;}
    // Stage 3 Bargaining
    if(noko1 > 0) {noko1--;} 
    if(noko2 > 0) {noko2--;} 
    if(noko3 > 0) {noko3--;} 
    if(noko4 > 0) {noko4--;} 

```

hello? same as only slower than

```arduino
    if(value1 > 0) {noko1 = 38;}
    if(value2 > 0) {noko2 = 38;}
    if(value3 > 0) {noko3 = 38;}
    if(value4 > 0) {noko4 = 38;}

```

One advice; spend time getting away from C++ Strings and learn C char array strings. At least then you won't be wasting your time.

You are doing a lot of useless manipulations the hard way and it seems like tou barely know what arrays are. Are you using snippets of code examples or getting gelp frim chatGPT? Either way. you don't learn to think well.

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<div class="post-metadata">

**Author:** ![hallowed31](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/hallowed31/32/1093680_2.png) [@hallowed31](https://forum.arduino.cc/u/hallowed31)\
**Post date:** [August 13, 2024, 5:24am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/9 "2024-08-13T05:24:47Z")

</div>

> [@foreyan](#):
>
> its actually just 4 integer data but separated with a comma. Here's the python code thats sending the data

I would nest these as chars in a switch/case structure that increments a byte every time you receive the next char and resets back to say, 0 once the fourth one arrives.

I mean, that's just how I would approach this code, I'm not saying to rewrite based on this, it's just how I would do it and telling Arduino to do stuff using just chars has always been plenty fast enough. I honestly don't have a better suggestion for you, just trying to tick a few things off before other helpers maybe offer a better suggestion.

I mean then you say that you don't think it's the Serial, but the pixels themselves so sorry I can't be more help than that.

In the off chance you do go for the Hail Mary and change your Serial input, the way to do single chars (or any Serial handling) is best illustrated to my knowledge in the immortal example of @Robin2. If you've never read this page, even if you don't use it for this project, it's well worth the time.

> [@Serial Input Basics - updated](https://forum.arduino.cc/t/serial-input-basics-updated/382007):
>
> Updated Version Please note that this is a revised version of the advice in [this earlier Thread](http://forum.arduino.cc/index.php?topic=288234.0) which has become very long. As far as possible I have kept the code examples identical or simplifed them slightly. It should not be necessary to refer to the older Thread, but feel free to do so. Contents The following sections are in this Tutorial Introduction Serial data is slow by Arduino standards Example 1 - Receiving single characters Why code is organized into functions Exampl…

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<div class="post-metadata">

**Author:** ![foreyan](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/foreyan/32/1038031_2.png) [@foreyan](https://forum.arduino.cc/u/foreyan)\
**Post date:** [August 13, 2024, 5:29am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/10 "2024-08-13T05:29:53Z")

</div>

i used this approach because it worked for me in the past when there was lesser data to handle but i guess its not efficient for this kind of operation. I'll keep it in mind and read up on the page. Thanks for the inputs!

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<div class="post-metadata">

**Author:** ![foreyan](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/foreyan/32/1038031_2.png) [@foreyan](https://forum.arduino.cc/u/foreyan)\
**Post date:** [August 13, 2024, 5:31am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/11 "2024-08-13T05:31:45Z")

</div>

the functionality is that i want a fading effect where the brightness slowly drops from (39x6) to (0x6) everytime the loop runs. And you're right I don't expose myself enough to using arrays

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<div class="post-metadata">

**Author:** ![GoForSmoke](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/goforsmoke/32/1127097_2.png) [@GoForSmoke](https://forum.arduino.cc/u/GoForSmoke)\
**Post date:** [August 13, 2024, 5:55am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/12 "2024-08-13T05:55:46Z")

</div>

maybe figure out and fix the first thing I showed and see what that does?

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<div class="post-metadata">

**Author:** ![foreyan](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/foreyan/32/1038031_2.png) [@foreyan](https://forum.arduino.cc/u/foreyan)\
**Post date:** [August 13, 2024, 6:06am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/13 "2024-08-13T06:06:46Z")

</div>

okay so I changed the noko1 to noko4 variables from global to local and modified the name to a different one, br1 to br4. The result is still the same with same speed as well.

As mentioned on the original post I also tried removing the variable noko1 to noko4 and simplified the calculation, also yield same result

---

<div class="post-metadata">

**Author:** ![GoForSmoke](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/goforsmoke/32/1127097_2.png) [@GoForSmoke](https://forum.arduino.cc/u/GoForSmoke)\
**Post date:** [August 13, 2024, 11:45am UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/14 "2024-08-13T11:45:53Z")

</div>

That's funny. To me, not making local copies of global variables would be a thing to do! Local variables get lost at the end of a function and void loop() is a function. If you make them static, that's different but just keeping them global is fine. The PROBLEM is having different variables with the same name, the compiler will use the local vars and whatever happens to them gets lost when loop() ends, getting rid of those should change how the sketch works.

---

<div class="post-metadata">

**Author:** ![davidefa](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/davidefa/32/1088935_2.png) [@davidefa](https://forum.arduino.cc/u/davidefa)\
**Post date:** [August 13, 2024, 12:00pm UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/15 "2024-08-13T12:00:26Z")

</div>

Also what is the flow of the program?  
As soon as it receives a 'command' from serial it writes the 8 leds ( once, without transitions)?  
To see where is the 'timing bootleneck' try adding some debug print, checking the show timestamp option in the serial debug ( ar use millis() or a higher resolution timer if needed )

---

<div class="post-metadata">

**Author:** ![rsmls](https://avatars.discourse-cdn.com/v4/letter/r/5daacb/32.png) [@rsmls](https://forum.arduino.cc/u/rsmls)\
**Post date:** [August 13, 2024, 12:10pm UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/16 "2024-08-13T12:10:06Z")

</div>

> [@foreyan](#):
>
> i want a fading effect where the brightness slowly drops from (39x6) to (0x6) everytime the loop runs

I see no for-loop that accomplishes this.  
Instead I see some code that basically just outputs light/color to a strip based on Serial inputs being fed to it.  
If you're trying to feed new color data through Serial into this Arduino, then this bit surely won't help with the responsiveness of the system:

> [@foreyan](#):
>
> ` delay(10);`

If all you really want is a fade effect, then what is the Serial input needed for?

---

<div class="post-metadata">

**Author:** ![GoForSmoke](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/goforsmoke/32/1127097_2.png) [@GoForSmoke](https://forum.arduino.cc/u/GoForSmoke)\
**Post date:** [August 13, 2024, 12:13pm UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/17 "2024-08-13T12:13:18Z")

</div>

> [@rsmls](#):
>
> I see no for-loop that accomplishes this.

Because void loop() should so as to not block execution.

added PS  
I had not looked into gow often there would be serial input or saw rgw delay(). Honestly there's so much wrong it's like where to start?

---

<div class="post-metadata">

**Author:** ![davidefa](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/davidefa/32/1088935_2.png) [@davidefa](https://forum.arduino.cc/u/davidefa)\
**Post date:** [August 13, 2024, 1:00pm UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/18 "2024-08-13T13:00:03Z")

</div>

but the code in the loop is ececuted only if a 'command' is received from the serial... ( so once per command )

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<div class="post-metadata">

**Author:** ![hallowed31](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/hallowed31/32/1093680_2.png) [@hallowed31](https://forum.arduino.cc/u/hallowed31)\
**Post date:** [August 13, 2024, 2:49pm UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/19 "2024-08-13T14:49:26Z")

</div>

> [@foreyan](#):
>
> As mentioned on the original post I also tried removing the variable noko1 to noko4 and simplified the calculation, also yield same result

Ok, I made a Wokwi that I think simulates your project.

> **[foreyanPixelSim - Wokwi ESP32, STM32, Arduino Simulator](https://wokwi.com/projects/406114671836765185)**
>
> Run IoT and embedded projects in your browser: ESP32, STM32, Arduino, Pi Pico, and more. No installation required!

I don't understand your program flow and there seems to be unnecessary calls to `strip.show();` (why at the end of `void setup()` ?

I tried changing the Serial `if` to a `while`, tried removing the `if (Serial.available() > ) {}` altogether (isn't that implicit in your subsequent call to `String input = Serial.readStringUntil('\n');`?) and I honestly can't help beyond this because I don't understand what this sketch is supposed to do.

For example, in the Wokwi, the pixels are always all green. Also, I can't seem to get them to turn off using "0,0,0,0" after they are all turned on with "1,1,1,1" input to Serial.

Also, this

```arduino
  if (Serial.available() > 0) {
    // Stage 1 Denial
    String input = Serial.readStringUntil('\n');
    parseInput(input);
    // Stage 2 Anger
    if (value1 > 0) {
      noko1 = 39;
    }

```

You have `// Stage 1 Denial` but whatever that is supposed to do...just reads input from the incoming Python data and does nothing with it before going to  
`// Stage 2 Anger`?

I must be missing something or maybe the Wokwi is not at all representative of where you're already at, I don't know but good luck.

---

<div class="post-metadata">

**Author:** ![foreyan](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/foreyan/32/1038031_2.png) [@foreyan](https://forum.arduino.cc/u/foreyan)\
**Post date:** [August 13, 2024, 3:26pm UTC](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291/20 "2024-08-13T15:26:57Z")

</div>

Sorry, I'll try to explain what it functionality is in detail

each set of data comes in format "0,0,0,0" and the arduino receives roughly 20 sets of such data per second. The incoming data value can change between 1 and 0.

Now for the arduino side, as you can see theres 2 if command (shown in stage 2 and 3) for each of the four data (so it calculates each variable individually).

In stage 2, whenever '1' is detected, it sets the variable value of 'noko' to 39. Else, the value of noko remains unchanged.

In stage 3, as long as the value of 'noko' is not zero, it will keep decreasing once per loop() cycle until it hits zero. This is what creates the fading effect.

In stage 4, 'neko' is just amplifying the value to map/scale brightness between 0 to 234 (39x6). Then it just sets each led brightness to value of 'neko'.

[Next page](https://forum.arduino.cc/t/code-processing-at-slow-speed/1291291.md?page=2)