I do not yet have the programming skills to solve a hardware timer clash between libraries, but I found a workaround which does function in my case by simply avoiding the timer library and do the reading of the inputs every time FastLED.show is called, using this code:
#include "FastLED.h"
byte Speed_1; // For reading analog pin 4.
CRGB Leds[256]; // Total amount of led's.
void setup() {
Serial.begin(115200);
FastLED.addLeds<WS2812B, 53, GRB>(Leds, 0, 256);
Read_Analog();
}
void loop() {
Speckle();
}
void Speckle() {
for (int x = 0; x < 256; x++) {
Leds[x] = CHSV(Speed_1, 100, 20);
Refresh();
delay(Speed_1);
}
}
void Refresh() {
Read_Analog();
FastLED.show();
}
void Read_Analog() {
Serial.println("In read_analog");
Speed_1 = analogRead(4) / 4;
}