Hi, i'm a complet beginner and i got myself the adruino starter kit. I have a question about the code. I get a error message with the if, else statement. attached is my code: int switchState = 0; void setup() { pinMode(3, OUTPUT); pinMode(4, OUTPUT); pinMode(5, OUTPUT); pinMode(2, INPUT); } void loop() { switchState = digitalRead(2); } if (switchState == LOW) { digitalWrite(3, HIGH); digitalWrite(4, LOW); digitalWrite(5, LOW); } else { digitalWrite(3, LOW); digitalWrite(4, LOW); digitalWrite(5, HIGH); delay(250); digitalWrite(4, High); digitalWrite(5, LOW); deley(250); } Can someone tell me what's wrong with it? Thans in advance!

Your if statement is not inside any function.

[image] hackbart77: void loop() { switchState = digitalRead(2); } That closing bracket completes the function loop() so the code after that isn't associated with a function but it needs to be. Move your closing bracket to the end of the file void loop() { switchState = digitalRead(2); if (switchState == LOW) { digitalWrite(3, HIGH); digitalWrite(4, LOW); digitalWrite(5, LOW); } else { digitalWrite(3, LOW); digitalWrite(4, LOW); digitalWrite(5, HIGH); delay(250); digitalWrite(4, High); digitalWrite(5, LOW); deley(250); } }

[image] blh64: Worked! Thanks soo much for your fast respons.

Hi @hackbart77 welcome to the arduino-Forum. Well done posting your code as a code-section in your very first posting. [image] So if your if - else is INSIDE the function loop() it will work. You should use meaningful names instead of numbers. You did not describe what your IO-pins 3,4,5 are So I named them at least IO_PinA, IO_PinB, IO_PinC int switchState = 0; const byte IO_PinA = 3; const byte IO_PinB = 4; const byte IO_PinC = 5; const byte mySwitchPin = 2; void setup() { pinMode(IO_PinA, OUTPUT); pinMode(IO_PinB, OUTPUT); pinMode(IO_PinC, OUTPUT); pinMode(mySwitchPin, INPUT); } void loop() { switchState = digitalRead(mySwitchPin); if (switchState == LOW) { digitalWrite(IO_PinA, HIGH); digitalWrite(IO_PinB, LOW); digitalWrite(IO_PinC, LOW); } else { digitalWrite(IO_PinA, LOW); digitalWrite(IO_PinB, LOW); digitalWrite(IO_PinC, HIGH); delay(250); // freeze_microcontroller_completely_stop_all_codeexecution_until_freezingtime_is_over digitalWrite(IO_PinB, High); digitalWrite(IO_PinC, LOW); delay(250); // freeze_microcontroller_completely_stop_all_codeexecution_until_freezingtime_is_over } } // END of function loop() You are using function delay(). In two days function delay() will cause problems to proceed any further iif you want to do two things in parallel. You should learn non-blocking timing right from the start. Unofrtunately the standard example about non-blocking timing is a real bad one. This standard example misses to explain the fundamental difference between delay() and non-blocking timing. The function delay() should have the name freeze_microcontroller_completely_stop_all_codeexecution_until_freezingtime_is_over() non-blocking timing makes the code loop very fast all the time and execute code that shall be executed all the time UNconcitional And the actions that shall be executed only after some time are executed CONDITIONAL with a timing-condition. Your code does a sequence of steps step 1 switch on IO-pin 5 step 2 wait for 250 milliseconds step 3 switch on IO-pin 4 step 4 wait for 250 milliseconds repeat if button is pressed then switch on io-pin 3 wait 250 milliseconds Here is a code that does a sequence to but in a non-blocking manner step 0 switch all off if switch is LOW step 1 switch on IOpin 5 step 2 wait 250 milliseconds step 3 switch on IO-pin 4 step 4 wait 250 milliseconds step 5 switch on io-pin 3 step 6 wait 250 milliseconds repeat int switchState = 0; const byte IO_PinA = 3; const byte IO_PinB = 4; const byte IO_PinC = 5; const byte mySwitchPin = 2; const byte sm_allOff = 0; const byte sm_switchOnA = 1; const byte sm_waitWithA_On = 2; const byte sm_switchOnC = 3; const byte sm_waitWithC_On = 4; const byte sm_switchOnB = 5; const byte sm_waitWithB_On = 6; byte mysequenceStep = sm_allOff; unsigned long myTimer; void setup() { pinMode(IO_PinA, OUTPUT); pinMode(IO_PinB, OUTPUT); pinMode(IO_PinC, OUTPUT); pinMode(mySwitchPin, INPUT); } void loop() { switchState = digitalRead(mySwitchPin); myStepSequence(); } // END of function loop() void myStepSequence() { switch (mysequenceStep) { case sm_allOff: if (switchState == LOW) { mysequenceStep = sm_switchOnA; } break; // IMMIDIATELY jump down to END-OF-SWITCH case sm_switchOnA: digitalWrite(IO_PinA, HIGH); digitalWrite(IO_PinB, LOW); digitalWrite(IO_PinC, LOW); myTimer = millis(); // store snapshot of time mysequenceStep = sm_waitWithA_On; break; // IMMIDIATELY jump down to END-OF-SWITCH case sm_waitWithA_On: // check if waiting-time has gone by if ( TimePeriodIsOver(myTimer, 250) ) { mysequenceStep = sm_switchOnC; } break; // IMMIDIATELY jump down to END-OF-SWITCH case sm_switchOnC: digitalWrite(IO_PinA, LOW); digitalWrite(IO_PinB, LOW); digitalWrite(IO_PinC, HIGH); myTimer = millis(); // store snapshot of time mysequenceStep = sm_waitWithC_On; break; // IMMIDIATELY jump down to END-OF-SWITCH case sm_waitWithC_On: if ( TimePeriodIsOver(myTimer, 250) ) { mysequenceStep = sm_switchOnB; } break; // IMMIDIATELY jump down to END-OF-SWITCH case sm_switchOnB: digitalWrite(IO_PinB, HIGH); digitalWrite(IO_PinC, LOW); myTimer = millis(); // store snapshot of time mysequenceStep = sm_waitWithB_On; break; // IMMIDIATELY jump down to END-OF-SWITCH case sm_waitWithB_On: if ( TimePeriodIsOver(myTimer, 250) ) { digitalWrite(IO_PinA, LOW); digitalWrite(IO_PinB, LOW); digitalWrite(IO_PinC, LOW); mysequenceStep = sm_allOff; } break; // IMMIDIATELY jump down to END-OF-SWITCH } // END-OF-SWITCH } // easy to use helper-function for non-blocking timing boolean TimePeriodIsOver (unsigned long &startOfPeriod, unsigned long TimePeriod) { unsigned long currentMillis = millis(); if ( currentMillis - startOfPeriod >= TimePeriod ) { // more time than TimePeriod has elapsed since last time if-condition was true startOfPeriod = currentMillis; // a new period starts right here so set new starttime return true; } else return false; // actual TimePeriod is NOT yet over } best regards Stefan

Dear @StefanL38 Thanks for the super detailed solution and the input with the non-blocking timing. I really appreciate your time to exlpain it since im planing the skill myself to do more with a Arduino then just operate some LED :stuck_out_tongue: The code works, but i definetly look into the non-blocking timing more in detail. Im looking very much forward to the future for more complex protects and all the good conversations her in the forum. Happy Coding!

[image] blh64: bracket [ open bracket ] close bracket { open brace } close brace

Bracket A bracket is either of two tall fore- or back-facing punctuation marks commonly used to isolate a segment of text or data from its surroundings. They come in four main pairs of shapes, as given in the box to the right, which also gives their names, that vary between British and American English. "Brackets", without further qualification, are in British English the (…) marks and in American English the […] marks. Other minor bracket shapes exist, such as (for example) slash or diagonal bracket...

[bracket2] [bracket1] [image] Waka Waka Bang Splat! It's been almost 13 years since two Calvin folks, Fred Bremmer and Steve Kroese, wrote the first poem for the internet, a poem composed entirely of computer keyboard characters. (this article is inaccurate... I read waka-waka-bang-splat in the '80s)

Help needed with debugging (Beginner)

Projects Programming

StefanL38 February 6, 2024, 4:44am 8

Example-code for timing based on millis() easier to understand through the use of example-numbers / avoiding delay() Tutorials

non-blocking timing. Execute code only from time to time. There are a lot of different ways to learn programming. This thread wants to add another approach that is different to the yet existing ones. UPDATE 06.01.2023 if you are mainly interested in applying non-blocking timing you can do a quick read of this short tutorial / demonstration If you are intersted in understanding the details how it works go on reading here. I use an everyday analogon in this post to explain the basic principle …

A Demo-Code explaining the switch-case state-machine and how to do things (almost) in parallel Tutorials

Hi everybody, if you look at the end of this first posting you see a list of links that show where this tutorial was used as a link. Go through this list to find additional information on how to apply this code This democode requires only the pure microcontroller without any hardware. You just open the serial monitor to watch the behaviour of the code. From time to time I enjoy writing demo-codes that want to explain programming-functionalities. There are a lot of different approachs to expl…

Explaining how to write NON-blocking all time responsive code Tutorials

Hi Everybody, from time to time I enjoy writing tutorials in my kind and style. My intention is to make it easy to understand. Though I'm aware: of the fact that one way of explaining things is not the best way for everybody. that the best experts about easyness-to-understand are: beginners . I want to encourage especially beginners to ask whatever question comes to their mind. I will use these questions as suggestion to improve the tutorial to become even more easy to understand. The u…

show post in topic

Topic		Replies	Views
If Statement problem Programming	49	978	June 15, 2025
Void loop and if else not looping Programming	9	212	March 6, 2026
Stuck in "if" statement? Programming	10	571	September 2, 2023
Bliniking a led with Millis() Programming	8	253	January 14, 2025
Delay() in main loop preventing ISR button detection Programming	11	1125	July 16, 2023

Help needed with debugging (Beginner)

Related topics