SENSORS/ACTUATORS

Raspberry Pi Pico - Blink multiple LED

This guide teaches you how to program a Raspberry Pi Pico to blink several LEDs at various speeds without using the time.sleep() function. It provides the code in two different methods:

Raspberry Pi Pico makes multiple LEDs blink.
Raspberry Pi Pico uses a array to blink multiple LEDs.

We will show how to do this with three LEDs. You can simply change it for two, four, or more LEDs.

Hardware Preparation

1	×	Raspberry Pi Pico W
1	×	Raspberry Pi Pico (Alternatively)
1	×	Micro USB Cable
1	×	LED
1	×	220 ohm resistor
1	×	Breadboard
1	×	Jumper Wires
1	×	(Optional) Screw Terminal Expansion Board for Raspberry Pi Pico

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables.

Overview of LED

Check out our detailed guide on LEDs. Learn about connecting the hardware, understanding how they function, setting them up with Raspberry Iron Pico, and how to program them. Learn more here:

Raspberry Pi Pico - LED tutorial

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Raspberry Pi Pico Code - Blink Multiple LEDs

To make multiple LEDs blink simultaneously, avoid using the time.sleep() function, as it halts other code execution and prevents LEDs from blinking at the same time. Instead, use the timestamp to manage the timing.

If you are new to programming and find it hard to handle the timing when blinking multiple LEDs, the DIYables_MicroPython_LED library simplifies it by managing the timing for you. This means you don't have to deal with timing issues on your own when using the library.

Detailed Instructions

Please follow these instructions step by step:

Ensure that Thonny IDE is installed on your computer.
Ensure that MicroPython firmware is installed on your Raspberry Pi Pico.
If this is your first time using a Raspberry Pico, refer to the Raspberry Pi Pico - Getting Started tutorial for detailed instructions.
Connect the Raspberry Pi Pico to the LEDs according to the provided diagram.
Connect the Raspberry Pi Pico to your computer using a USB cable.
Launch the Thonny IDE on your computer.
On Thonny IDE, select MicroPython (Raspberry Pi Pico) Interpreter by navigating to Tools Options.
In the Interpreter tab, select MicroPython (Raspberry Pi Pico) from the drop-down menu.
Ensure the correct port is selected. Thonny IDE should automatically detect the port, but you may need to select it manually (e.g., COM3 on Windows or /dev/ttyACM0 on Linux).
On Thonny IDE, Navigate to the Tools Manage packages on the Thonny IDE.
Search “DIYables-MicroPython-LED”, then find the LED library created by DIYables.
Click on DIYables-MicroPython-LED, then click Install button to install LED library.

Copy the above code and paste it to the Thonny IDE's editor.
Save the script to your Raspberry Pi Pico by:

Click the Save button, or use Ctrl+S keys.
In the save dialog, you will see two sections: This computer and Raspberry Pi Pico. Select Raspberry Pi Pico
Save the file as main.py

Click the green Run button (or press F5) to run the script. The script will execute.
Check out the message in the Shell at the bottom of Thonny.
Check if the LED is turned on or off.

Raspberry Pi Pico Code - Blink Multiple LEDs by using array

We can improve the above code by using an array of LEDs. The code below uses this array to handle LED objects.

""" This Raspberry Pi Pico MicroPython code was developed by newbiely.com This Raspberry Pi Pico code is made available for public use without any restriction For comprehensive instructions and wiring diagrams, please visit: https://newbiely.com/tutorials/raspberry-pico/raspberry-pi-pico-blink-multiple-led """ from DIYables_MicroPython_LED import LED, LED_DELAY, LED_BLINKING, LED_IDLE, CTRL_ANODE # Define LED pins PIN_LED_1 = 22 # The Raspberry Pi Pico pin connected to the LED 1 (GP22) PIN_LED_2 = 26 # The Raspberry Pi Pico pin connected to the LED 2 (GP26) PIN_LED_3 = 27 # The Raspberry Pi Pico pin connected to the LED 3 (GP27) # Create an array of LED objects led_array = [ LED(PIN_LED_1, CTRL_ANODE), # create ezLED object that attach to pin PIN_LED_1 LED(PIN_LED_2, CTRL_ANODE), # create ezLED object that attach to pin PIN_LED_2 LED(PIN_LED_3, CTRL_ANODE) # create ezLED object that attach to pin PIN_LED_3 ] led_array[0].blink(500, 500) # 500ms ON, 500ms OFF, blink immediately led_array[1].blink_with_duration(100, 100, 5000) # 100ms ON, 100ms OFF, blink for 5 seconds, blink immediately led_array[2].blink_n_times(250, 750, 10) # 250ms ON, 750ms OFF, repeat 10 times, blink immediately # Function to print the state of an LED def print_state(state, led_index): if state == LED_DELAY: print(f"LED {led_index + 1} DELAYING") elif state == LED_BLINKING: print(f"LED {led_index + 1} BLINKING") elif state == LED_IDLE: print(f"LED {led_index + 1} BLINK ENDED") # Track the previous states of the LEDs previous_states = [None] * len(led_array) # Main loop while True: # Update each LED state for i, led in enumerate(led_array): led.loop() # MUST call the led.loop() function in loop() # Get the current state of the LED current_state = led.get_state() # Print the state only if it has changed if current_state != previous_states[i]: print_state(current_state, i) previous_states[i] = current_state # Update the previous state # DO SOMETHING HERE

With the DIYables_MicroPython_LED library, you can easily make multiple LEDs blink like this:

Make multiple LEDs blink at different frequencies.
Make multiple LEDs begin blinking at different time.
Set each LED to blink for a specific length of time.
Set each LED to blink a specific number of times.

Video Tutorial

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