Hello Everyone! I am using ESP32 to read an analog input and to blink a LED. My problem is that delay after reading analog input is interfering OFF duration of LED. LED remains ON for the duration of delay added after ON command but it remains OFF for the duration of delay added after OFF command plus duration of delay added after analogread(). Please help to run LED ON/OFF independent of delay after analogread. // Potentiometer is connected to GPIO 34 (Analog ADC1_CH6) const int potPin = 34; // variable for storing the potentiometer value int potValue = 0; void setup() { Serial.begin(115200); delay(1000); // initialize digital pin GPIO18 as an output. pinMode(18, OUTPUT); } void loop() { // Reading potentiometer value potValue = analogRead(potPin); Serial.print("Analog value: "); Serial.println(potValue); delay(2000); digitalWrite(18, HIGH); // turn the LED on delay(500); // wait for 500 milliseconds digitalWrite(18, LOW); // turn the LED off delay(500); // wait for 500 milliseconds }

[image] asharet: delay after reading analog input is interfering This is the result of "blocking code." The function delay() stops the mcu from processing any other commands until the delay time is finished. What you need is a timing mechanism. A great place to start is "blink without delay()" This will show you how to use timing to make an event happen. After that, find "doing multiple things" Here is a simulation that I used to get up to speed on timing... small description is in the code. [image] eventTiming - Wokwi ESP32, STM32, Arduino Simulator Run IoT and embedded projects in your browser: ESP32, STM32, Arduino, Pi Pico, and more. No installation required!

Take a look at ESP32 Dual Core with Arduino IDE | Random Nerd Tutorials Or consider writing your own non blocking code. See Using millis() for timing. A beginners guide, Several things at the same time and the BlinkWithoutDelay example in the IDE

[image] asharet: Please help to run LED ON/OFF independent of delay the measurement/printing should be done every two seconds. the blinking will be done every half second. As already mentioned, avoid delay(). Use Blink Without Delay | Arduino Documentation to see how to blink the LED. Apply the same concept for the analogRead/Serial print. If you get stuck - post your updated code, then we can help you.

Not sure if you are interested in coding the solution on your own or just in a solution for your specific task ... If it's a solution feel free to look here https://wokwi.com/projects/383811900704320513 Sketch /* Forum: https://forum.arduino.cc/t/how-to-run-two-events-independently/1199135 Wokwi: https://wokwi.com/projects/383811900704320513 */ // Potentiometer is connected to GPIO 34 (Analog ADC1_CH6) // The last time a measurement was performed will be stored in lastMeasurement // variable for storing the potentiometer valueconstexpr byte potPin = 34; constexpr byte potPin = 34; unsigned long lastMeasurement = 0; int potValue = 0; // Led is connected to pin 18 // lastBlinkTime holds the controller time in ms since last reset when the led pin was changed // state holds the state the led pin has been set to constexpr byte ledPin = 18; unsigned long lastBlinkTime = 0; byte state = HIGH; void setup() { Serial.begin(115200); delay(1000); // initialize digital ledPin as output. pinMode(ledPin, OUTPUT); } void loop() { blinkEvery(500); measureEvery(2000); } // The content after the if-condition is only performed // when "interval" ms are expired since the last measurement void measureEvery(unsigned long interval) { if (millis() - lastMeasurement >= interval) { lastMeasurement = millis(); // Reading potentiometer value potValue = analogRead(potPin); Serial.print("Analog value: "); Serial.println(potValue); } } // The content after the if-condition is only performed // when "interval" ms are expired since the last change of the // digital pin state void blinkEvery(unsigned long interval) { if (millis() - lastBlinkTime >= interval) { lastBlinkTime = millis(); state = !state; digitalWrite(ledPin, state); } } Good luck!

[image] asharet: Hello Everyone! I am using ESP32 to read an analog input and to blink a LED. 1. How often (I mean how many times per sec) you wish to read the analog input? 2. What are the On-time (for how long the LED remains On) and Off-time (for how long the LED remains Off) of your blinking LED? 3. It is seen from your sketch of Post #1 that you are acquiring input signal at at every 1200 ms (200 + 500 + 500) interval. Your LED is turned On at every 1200 ms interval and remains On for 500 ms. The LED is turned Off at every 1200 ms interval and remains Off for 500 ms. This is a process of sequentila operation whose timing diagram is given below (Fig-1). [concurrentExec] Figure-1: 4. You want to feel that the two tasks (ADC acquisition at 200 ms interval) and LED blinking at 1-sec interval should happen concurrently/simultaneously. The tming diagram would be something like Fig-2. (Note that the tasks are asynchronous though timing lines are aligned.) [concurrentExec2] Figure-2: 5. There is only one processor in your MCU which must execute tasks one-after-another in a sequential manner. How can it perform tasks simultaneously when it (the MCU) is a Serial Device? It can't; but, there is mechanism to do do it; where, the eyes are hyptonized to believe that the tasks are being executed concurrently (untrue parallelism.) 6. Many ways have been prescribed in the previous posts to blink the LEDs concurrently. I wish to do it using FreeRTOS Library that is supported by ESP32 and UNOR4. .... pending 7. Example: Blinking three LEDs concurrently using FreeRTOS Library. This sketch can be modified for "two LEDs" or "two LED + one ADC channe (Fig-3)". Schematic: [esp32-3led] Figure-1: Timing Diagram: [taskStateDiag] Figure-2: Sketch: //function declarations TaskHandle_t Task10Handle; TaskHandle_t Task11Handle; //GPIO definitions #define LED 2 #define LED10 21 #define LED11 22 //task creation using FreeRTOS.h Librray functions void setup() { Serial.begin(9600); pinMode(LED, OUTPUT); pinMode(LED10, OUTPUT); pinMode(LED11, OUTPUT); xTaskCreatePinnedToCore(Task10, "Task-10", 2048, NULL, 2, &Task10Handle, 1); xTaskCreatePinnedToCore(Task11, "Task-11", 2048, NULL, 3, &Task10Handle, 1); } //LED blinks at 2000 ms interval void loop() { digitalWrite(LED, HIGH); vTaskDelay(pdMS_TO_TICKS(2000)); // Delay the task for 100 milliseconds digitalWrite(LED, LOW); vTaskDelay(pdMS_TO_TICKS(2000)); } //LED10 blins at 1000 ms interval void Task10(void *pvParameters) { while (true) { digitalWrite(LED10, HIGH); vTaskDelay(pdMS_TO_TICKS(1000)); // Delay the task for 1000 milliseconds digitalWrite(LED10, LOW); vTaskDelay(pdMS_TO_TICKS(1000)); } } //LED11 blinks at 500 ms interval void Task11(void *pvParameters) { while (true) { digitalWrite(LED11, HIGH); vTaskDelay(pdMS_TO_TICKS(500)); // Delay the task for 500 milliseconds digitalWrite(LED11, LOW); vTaskDelay(pdMS_TO_TICKS(500)); } } 8. Upload sketch of Step-7 and observe that the three LEDs are blinking concurrentlt at their respective intervals. 9. Eexrcise: Blinking Two LEDs and one ADC channel acquisition concurrently. [esp32-2ledAdc] Figure-3:

[image] asharet: Please help to run LED ON/OFF independent of delay after analogread. look this over // multiple things const byte PotPin = 34; const byte LedPin = 18; // Capitalize Constants unsigned long msec; // ----------------------------------------------------------------------------- void taskPot () { static unsigned long msecLast; if (msec - msecLast >= 2000) { msecLast = msec; Serial.print ("Analog value: "); Serial.println (analogRead (PotPin)); } } // ----------------------------------------------------------------------------- void taskLed () { static unsigned long msecLast; static int state; if (msec - msecLast >= 500) { msecLast = msec; if (HIGH == state) state = LOW; else state = HIGH; digitalWrite (LedPin, state); } } // ----------------------------------------------------------------------------- void loop () { msec = millis (); taskPot (); taskLed (); } // ----------------------------------------------------------------------------- void setup () { Serial.begin (115200); pinMode (LedPin, OUTPUT); }

Thanks for your help. "blink without delay" is working well. But its ON and OFF duration is same. What modification is required to obtain desired ON and OFF duration?

Thanks for reply. I think at #3, time duration should be 2000+500+500=3000 and not 200+500+500=1200. Is'nt it?

When the timing period comes to an end change the timing period to the next one required. Something like if (period == 1000) { period = 5000; } else { period = 1000; }

[image] GolamMostafa: Timing Diagram: [taskStateDiag] Did you draw this diagram yourself? What program did you use?

How to run two events independently

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DaveX December 11, 2023, 9:24pm 12

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How to run two events independently

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