Hi I am using an esp32, due to a lack of available pins, I need to use the same pin for a button that has a built-in LED. The idea is that when I press the button, the LED turns on for a few seconds. After doing some research, I found that certain pins are suitable for this purpose, but I want to make sure they are safe to use this way. I tested it with pin 21, and it worked as I wanted, but I don’t want to risk damaging the board. The pins I’m considering using are: p2, p4, p5, p16, p17, p18, p19, p21, p22, p23. Are these pins safe to use for controlling a button with an integrated LED on the same pin?

Indeed. It would be helpful to know which board. And you say that the button has a built-in LED? Does it also have a built-in LED resistor? If not, then you will need an external current limiting resistor. Perhaps you could provide a link to the board and and the button part you are using?

You can't hurt the board by connecting a PB and/or LED.

[image] cuasitos: need to use the same pin for a button that has a built-in LED This shows how to have a LED and switch on a GPIO at the same time: [image] [image] Share tips you have come across General Electronics Got a request for the code that goes with post #334, (Using a LED and switch on the same I/O pin). Forgot to add it to that post frowning so here it is now: /* Demonstration how to use a pin as an output to a LED and at the same time, as an input from a switch. Note: The LED(s) 'must' be connected to +5V (CA) through a series resistor. The switch is connected to GND through a 240 ohm resistor. Typical setup for SMD LEDs: +5V White LED - 4.7K - I/O PIN - 240R - Switch - GND … [image] Switch and LED on the same pin, suggestions FYI Programming Simplified Sketch: /* Demonstration how to use a pin as a output for a LED and as an input for a switch. Note: The LED 'must' be connected to +5V through a 470 ohm (or larger) resistor. The switch is connected to GND through a 220 ohm resistor. Version YY/MM/DD 1.00 16/12/11 Running code */ //********************************************************************** //G l o b a l v a r i a b l e s //**********************************************************************…

Sorry the board is an esp32 and I try on pin 21 and works but I don't know for the others pins

Look at a pinout diagram for ESP32. If those other pins are marked as GPIO pins like pin 21 then it should be ok. When connecting a button and led to the same pin, if the led remains lit for some time, it will not be possible to read the pin to detect if the button is still pressed or has been pressed again. However, by changing the pin mode back to input, reading the pin and then immediately changing it back to output again, any flickering in the led should not be too noticeable. @LarryD are resistors R7-12 necessary? Also why are R1-6 different values? Some of those values seem a little too high for led current limiting.

[image] PaulRB: are resistors R7-12 necessary? They probably prevent problems in case the GPIOs are accidentally configured as high outputs.

[image] LarryD: This shows how to have a LED and switch on a GPIO at the same time But, as long as the buttons are pressed, the LEDs remain on. It depends on whether this is acceptable. It's crucial to understand how OP's "button that has a built-in LED" is wired.

[image] Claudio_FF: in case the GPIOs are accidentally configured as high Possibly. But we normally recommend to connect an ordinary button (without an LED) from the Arduino pin to ground, with no resistor, without much concern that the pin might be accidentally configured as high. With these buttons which have LEDs, it will be necessary to switch between input and output modes, which you could argue increases the risk. But pins default to low when set to output, so I don't see it as a significantly increased risk. I guess the danger is that a beginner thinks the pin must be set to high rather than input to switch off the LED.

Yes, this precaution can save a lot of headaches, especially for beginners who regularly connect LEDs without a resistor :roll_eyes: Somewhere, they even recommend always putting a resistor in series with a GPIO.

Uing the fllowing pins with a button with an incorporated led?

Projects General Guidance

LarryD May 24, 2025, 11:49pm 5

This shows how to have a LED and switch on a GPIO at the same time:

image1380×952 186 KB

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Uing the fllowing pins with a button with an incorporated led?

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