I was trying the fading example and experimenting with 2 LEDs and although it works but I couldn't get the required half cycle. int ledPin = 5; int ledPin2 = 3; void setup() { pinMode(ledPin, OUTPUT); pinMode(ledPin2, OUTPUT); } void loop() { // fade in from min to max in increments of 5 points: for (int fadeValue = 0 ; fadeValue = 0; fadeValue = fadeValue-5) { // sets the value (range from 0 to 255): analogWrite(ledPin, fadeValue); // wait for 30 milliseconds to see the dimming effect delay(30); } // fade in from min to max in increments of 5 points: for (int fadeValue = 0 ; fadeValue = 0; fadeValue = fadeValue-5) { // sets the value (range from 0 to 255): analogWrite(ledPin2, fadeValue); // wait for 30 milliseconds to see the dimming effect delay(30); } } My code works like red LED glows and fades and then green LED glows and fades. When red LED is on the green will be off and vice-versa. What I want is to get the red LED to glow and when it reaches full bright on then the green must slowly start glowing and when the red is faded completely then the green must glow bright fully. I'm explain it better with a graph. [wave] Graph A shows how my code works Graph B is what I want to do. Is it possible to do that?

[image] Noobian: if (brightnessA = 255 || brightnessB = 255) { fadeAmountA = -fadeAmountA; fadeAmountB = -fadeAmountB; } why would you reverse the direction of both if only one hit the top of bottom value ? may be something like this const byte ledAPin = 3; // the PWM pin the LED is attached to const byte ledBPin = 9; int brightnessA = 0; // how bright the LED is int brightnessB = 127; // how bright the LED is int fadeAmountA = 5; // how many points to fade the LED by int fadeAmountB = 5; // how many points to fade the LED by // the setup routine runs once when you press reset: void setup() { pinMode(ledAPin, OUTPUT); pinMode(ledBPin, OUTPUT); Serial.begin(115200); } // the loop routine runs over and over again forever: void loop() { analogWrite(ledAPin, brightnessA); analogWrite(ledBPin, brightnessB); // to see the values on the Serial plotter Serial.print(brightnessA); Serial.write('\t'); Serial.println(brightnessB); // change the brightness for next time through the loop: brightnessA += fadeAmountA; if (brightnessA 255 ) { // we overshot, time to change direction if (fadeAmountA > 0) brightnessA = 255; // we were going up else brightnessA = 0; // we were going down fadeAmountA = -fadeAmountA; } brightnessB += fadeAmountB; if (brightnessB 255 ) { // we overshot, time to change direction if (fadeAmountB > 0) brightnessB = 255; // we were going up else brightnessB = 0; // we were going down fadeAmountB = -fadeAmountB; } delay(10); }

[image] Noobian: Is it possible to do that? Which Arduino are you using?

look this over - corrected should be msec0 += MsecPeriod; const int MinVal = 150; const int MaxVal = 255; const int N = 2; const byte Pin [N] = { 10, 11 }; // 5, 3 int dir [N] = { 1, 1 }; int val [N] = { MinVal, (MaxVal + MinVal) / 2 }; const unsigned long MsecPeriod = 150; unsigned long msec0; bool dbg = true; char s [90]; // ----------------------------------------------------------------------------- void loop() { unsigned long msec = millis (); if (msec - msec0 >= MsecPeriod) { msec0 += MsecPeriod; for (int n = 0; n = val [n] || MaxVal <= val [n]) dir [n] = -dir [n]; if (dbg) { sprintf (s, " %d: %2d %4d", n,dir [n], val [n]); Serial.print (s); } } if (dbg) Serial.println (); } } // ----------------------------------------------------------------------------- void setup() { Serial.begin (115200); for (int n = 0; n < N; n++) pinMode (Pin [n], OUTPUT); }

It looks sophisticated but it works. I changed MinVal from 150 to 5 and it looks better. How can I change the interval time to make it fade longer?.

[image] Noobian: How can I change the interval time to make it fade longer?. MsecPeriod [image] Noobian: It looks sophisticated not very just a single timer with an array of "things" instead of separate code to up and down, uses a direction variable starts one at the halfway point which keeps it out of phase KISS

[image] Noobian: Graph B is what I want to do. Is it possible to do that? Yes. In learning the code in the links in @J-M-L post #2, you will use a running counter to start each LED phase. The first LED will start increasing the PWM level at "time 0/100" and count toward "100/100." As the first LED crosses "50/100," the second LED PWM level will start counting from "0/100" toward "100/100." After the first LED reaches "100/100," it will begin to decrease the PWM level to the LED, as LED2 continues increasing to "100/100." I see your curves are sinusoidal, so the increases will not be 1:1, but here is a grid of how it will look: (I used my fingers to count these... not certain they are right... ) # LED1 LED2 0 0 0 1 1 0 2 2 0 . . 49 49 0 50 50 1 51 51 2 . . 98 98 48 99 99 49 100 98 50 101 97 51 . . 148 50 98 149 49 99 150 48 98 151 47 97 . . 198 1 51 199 0 50 200 1 49

MsecPeriod is not changing the interval. Increasing the value makes just the initial program/boot to be delayed .

Hello Noobian Take a view and mod then sketch to your project needs. //https://forum.arduino.cc/t/two-leds-fading-at-half-cycle-rate/1334436 //https://europe1.discourse-cdn.com/arduino/original/4X/7/e/0/7e0ee1e51f1df32e30893550c85f0dd33244fb0e.jpeg #define ProjectName "Two LEDs fading at half cycle rate" #define NotesOnRelease "Arduino MEGA tested" // make names enum TimerEvent {NotExpired, Expired}; enum UpDown {Up, Down}; // make variables uint32_t currentMillis = millis(); constexpr uint8_t LedPins[] {5, 3}; constexpr uint16_t StartValue[] {0, 128}; constexpr uint32_t Interval {35}; // make structures //----------------------------------------- struct TIMER { uint32_t interval; uint32_t now; uint8_t expired(uint32_t currentMillis) { uint8_t timerEvent = currentMillis - now >= interval ; if (timerEvent == Expired) now = currentMillis; return timerEvent; } }; struct DIMLED { uint8_t led; uint16_t value; uint8_t upDown; TIMER dimmer; void make(uint8_t led_, uint16_t value_, uint32_t interval_ ) { led = led_; pinMode(led, OUTPUT); value = value_; upDown = Up; dimmer.interval = interval_; } void exec(uint32_t currentMillis) { if (dimmer.expired(currentMillis) == Expired) { (upDown == Up) ? value++ : value--; if ((value == 0 ) or (value == 255)) upDown = upDown ? Up : Down; analogWrite(led, value); } } } dimLeds[sizeof(LedPins)]; //----------------------------------------- // make objects //----------------------------------------- // make support void heartBeat(const uint8_t LedPin, uint32_t currentMillis) { static bool setUp = false; if (setUp == false) pinMode (LedPin, OUTPUT), setUp = true; digitalWrite(LedPin, (currentMillis / 500) % 2); } // make application void setup() { Serial.begin(115200); for (uint8_t n = 0; n and off we go\n"); } void loop() { currentMillis = millis(); for (auto &dimLed : dimLeds) dimLed.exec(currentMillis); } //------ Have a nice day and enjoy coding in C++.

[image] Noobian: MsecPeriod is not changing the interval. see corrected code

Two LEDs fading at half cycle rate

Projects Programming

J-M-L December 21, 2024, 9:45am 2

your code is sequential and blocking with delay. You need to get rid of the delays.

For extra information and examples look at

Using millis() for timing. A beginners guide
Several things at the same time
Flashing multiple LEDs at the same time

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Two LEDs fading at half cycle rate

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