/products/arduino/b/blog/posts/why-does-it-work-sometimesWhy does this code loaded on a Nano knockoff work sometimes, if I clearly missed a section of code? int LEDPin = 9;int ButtonPin = 8;int RelayPin = 2; void setup() { // initialize digital pin LED_BUILTIN as an output. pinMode(LEDPin, OUTPUT); pinModeen-USTelligent Community 12https://community.element14.com/products/arduino/b/blog/posts/why-does-it-work-sometimesSun, 10 Jul 2022 08:04:30 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:a883c194-ce81-48e6-ae79-05da9af5bbe3misaz1<p>Do you connect pull-up resistor on button pin? Describe or post schematics of your button connection.</p><img src="https://community.element14.com/aggbug?PostID=23939&AppID=145&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/products/arduino/b/blog/posts/why-does-it-work-sometimesSat, 09 Jul 2022 15:55:46 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:a883c194-ce81-48e6-ae79-05da9af5bbe3ralphjy0<p>I would guess that your two breadboard circuits are not hooked up identically.&nbsp; Are the other components on the breadboards besides the Nano the same?&nbsp; What Nano knockoff are you using?&nbsp; I think Jan&#39;s suggestion of measuring voltages will lead you to the cause.</p><img src="https://community.element14.com/aggbug?PostID=23939&AppID=145&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/products/arduino/b/blog/posts/why-does-it-work-sometimesSat, 09 Jul 2022 15:25:09 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:a883c194-ce81-48e6-ae79-05da9af5bbe3Jan Cumps1<p>The compiler did not show an error because you made no c++ syntax error.</p> <p>For the ATMxxx type of Arduinos, if you don&#39;t set PIN mode, they are high-Z, floating. Undetermined.&nbsp;</p> <p>If you still havethe working and non-working setups, put a volt meter on the pin and check if you measure a difference ...</p><img src="https://community.element14.com/aggbug?PostID=23939&AppID=145&AppType=Weblog&ContentType=0" width="1" height="1">