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So this is my first time working with ESP32 or any MCU at all and I'm trying to blink an external LED connected to my GPIO16 pin but it doesn´t seem to be working. My board is a 38pin ESP32 with only one internal LED connected to pin 1 (not to pin 2 as many other esp32 dev boards) which I was actually able to blink with the blink example program.

I've tried connecting my external LED positive terminal to GPIO17 and GPIO18 as well but still doesn't work. I'm grounding my LED negative terminal with one of the GND pins of the dev board and I've also tried using the other 2 GND pins available but the result is the same.

In the Arduino IDE I'm using ESP32 Dev Module as my board in the boards manager and the serial communication seems to be working just fine, I'm just not being able to output the HIGH and LOW signals to light up my LED.

The limiting resistor I'm using is a 220 Ohm.

Here's the code I've been trying to achieve this:

int ledPin = 16;

void setup() {
  pinMode(ledPin, OUTPUT);
}

void loop () {
  digitalWrite(ledPin,HIGH);
  delay(1000);
  digitalWrite(ledPin,LOW);
  delay(1000);
}

Is it possible that my pins are outputting a very low voltage or that they might not work?

I leave a picture of my pinout. Thank you very much in advance!!

ESP32 Dev Module 38 Pin Layout

luispr17
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  • If you don't have a digital multimeter and you want to play with circuits, you should get one. Just for times like this. :) I assume that when you set your `ledPin` to 16, you are connecting to GPIO16, not referencing the other numbers on your image, correct? GPIO > LED+, and LED- > resistor > GND (GND taken from any of your GND pins) should work fine, as well as GPIO > resistor > LED+, and LED- > GND. Also, you know the long lead on the LED is the + lead (anode).... right? – lurker May 19 '21 at 02:39
  • Do a `pinMode(LED_BUILTIN, OUTPUT)` and then in the loop do `Serial.println(LED_BUITLIN)` to find out which pin the built-in LED is connected to, and then connect your external LED with the resistor between the pin and ground. Report back if your external LED is blinking together with the built-in LED or not? – hcheung May 19 '21 at 12:37

0 Answers0