// Replace with your Blynk authentication token char auth[] = "YOUR_BLYNK_AUTH_TOKEN";
Connect an LED's anode (longer leg) to GPIO 2 (often labelled D4 on a NodeMCU) and its cathode (shorter leg) to a GND pin via a 220-ohm resistor. Most modern ESP8266 boards have a built-in LED on GPIO 2, which you can use for testing. blynksimpleesp8266 h library zip