NodeMCU as UDP client to control ws2812

[qinzheng]

Platform

• Hardware: NodeMCU 0.9
• Development Env: Arduino IDE
• Operating System: MacOS

Settings in IDE

• Module: Nodemcu
• Flash Size: [4MB/1MB]
• lwip Variant: v2 Lower Memory
• CPU Frequency: 160MHz
• Upload Using: SERIAL
• Upload Speed: 115200

Problem Description

I used nodmcu as udp client to recives ws2812 datas,each pixel take up 3 bytes and I have 500pixels or more,but once it exceeds 492 pixels, the client can no longer receive data

Sketch

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <FastLED.h>

#define DATA_PIN    3
#define LED_TYPE    WS2812B
#define COLOR_ORDER GRB
#define NUM_LEDS    500
#define BRIGHTNESS  128
#define UDP_PORT 3000

const char* ssid = "Rect";
const char* password = "11111111";
const unsigned int wifi_timeout = 30000;

CRGB leds[NUM_LEDS];
WiFiUDP Udp;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  delay(10);

  // 初始化灯带
  FastLED.addLeds<LED_TYPE, DATA_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);
  FastLED.setBrightness(BRIGHTNESS);

  // 连接wifi
  setup_wifi();

  // 开启udp
  Udp.begin(UDP_PORT);
  Serial.printf("Now listening at IP %s, UDP port %d\n", WiFi.localIP().toString().c_str(), UDP_PORT);
}

// 设置wifi
void setup_wifi() {
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  
  unsigned long connect_start = millis();
  while(WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
  Serial.println();
}

void loop() {
  // put your main code here, to run repeatedly:
  int packetSize = Udp.parsePacket();
  while (packetSize > 0) {
    Udp.read((char*)leds, NUM_LEDS * 3);
  }
  FastLED.show();
}

[d-a-v]

MTU is 1500 bytes, udp+ip header is 28 bytes, it leaves 1472 bytes for user data.
Did you try with two packets ?

[macfletzi]

I use 120 Pixel with MQTT, but this crashes always after a few minutes.

Without FastLED.show(), no problems.

Because of the hard timing for the ws2812, i think, so many pixels steal too much time from the wifi stack.
Has anyone experience, how many pixels work with NodeMCU?

(With 8-Bit AVR I use more than 1500 pixels without any problems)