LED Button Lab

Welcome to the LED Button Lab

Monty waving welcome An LED button is a button and an LED combined in one part! Press it to turn on the light — or use code to control the light while the button waits for your touch. Let's build something amazing!

What Is an LED Button?

An LED button is a push button that has a small LED built into the cap. When the LED is on, the button glows. This makes it easy to see which button is active — perfect for game controllers, status panels, and interactive projects.

The Grove LED Button from Seeed Studio is a popular choice. It has a four-pin Grove connector:

Pin	Signal
1	Button signal (HIGH when not pressed, LOW when pressed)
2	LED signal (HIGH to turn LED on)
3	GND
4	VCC (3.3 V)

You can also use any push button paired with a separate LED — the wiring and code are the same.

Parts You Need

Part	Quantity	Approximate Cost
Raspberry Pi Pico	1	$4
Grove LED Button (or button + LED)	1	$2–$3
Solderless breadboard	1	$3
Jumper wires	4	—
330 Ω resistor (if using separate LED)	1	<$1

Wiring Steps

Connect VCC on the button to 3.3 V (pin 36) on the Pico.
Connect GND on the button to any GND pin on the Pico.
Connect the button signal wire to GP14 on the Pico.
Connect the LED signal wire to GP15 on the Pico.

Watch Out!

Monty warning If you use a separate LED instead of a Grove button, always put a 330 Ω resistor in series with the LED. Without a resistor, too much current will flow and the LED will burn out.

Sample Program: Button Toggles LED

This program turns the LED on when you press the button and off when you press it again.

from machine import Pin
import time

# Set up the button as an input with the internal pull-up resistor enabled
button = Pin(14, Pin.IN, Pin.PULL_UP)

# Set up the LED as an output
led = Pin(15, Pin.OUT)

led_state = False  # start with the LED off

while True:
    if button.value() == 0:        # button pressed (pulls pin LOW)
        led_state = not led_state  # flip the LED state
        led.value(led_state)       # apply the new state
        time.sleep(0.3)            # short delay to avoid bouncing
    time.sleep(0.05)               # check the button 20 times per second

What Each Line Does

Line	Purpose
`Pin(14, Pin.IN, Pin.PULL_UP)`	Button input with internal pull-up (reads HIGH when not pressed)
`Pin(15, Pin.OUT)`	LED output pin
`button.value() == 0`	True when the button is pressed (pulls pin to GND)
`not led_state`	Flips True→False or False→True
`time.sleep(0.3)`	Waits 300 ms so one press = one toggle, not many

Key Idea

Monty thinking Pin.PULL_UP turns on a tiny resistor inside the Pico that keeps the pin HIGH when the button is not pressed. When you press the button, it connects the pin to GND, so the pin goes LOW. That is how the Pico detects a press.

Sample Program: LED Stays On While Button Is Held

This simpler version lights the LED only while you hold the button down:

from machine import Pin
import time

button = Pin(14, Pin.IN, Pin.PULL_UP)
led = Pin(15, Pin.OUT)

while True:
    if button.value() == 0:  # button is being held down
        led.value(1)         # turn LED on
    else:
        led.value(0)         # turn LED off
    time.sleep(0.02)         # check 50 times per second

Monty's Tip

Monty giving a tip Try connecting the LED to a PWM pin and fading it in slowly when you press the button. Use PWM(Pin(15)) and duty_u16() to control brightness!

Great Work!

Monty celebrating You have wired up an LED button and controlled it two different ways. Next, try the 7-segment display to show numbers on screen!