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In this project, we will use a PIR motion sensor to detect human movement, once an intruder’s motions is detected, then Pico will trig a buzzer alarm. This is a typical application used in many home security system.

  1. Raspberry Pi Pico board and microUSB cable
  2. A computer to run Thonny Python IDE
  3. A breadboard
  4. PIR motion sensor x 1 pc
  5. Active Buzzer (low voltage trig) x 1 pc
  6. Some jumper wires

In above circuit graph, you can see that:
PIR sensor VCC pin connected to VBUS(5V)
PIR sensor GND pin connected to GND
PIR sensor OUT pin connected to GP16
buzzer I/O pin   connected to GP15

You can download lesson6 python code from

You can use Thonny to open and load it to Pico later.
Here is the full code with comments:

from machine import Pin #import Pin library
from time import sleep # import sleep function

buzzer = Pin(15, Pin.OUT,Pin.PULL_UP) #set GP15 as digital output pin for buzzer
pir = Pin(16, Pin.IN,Pin.PULL_DOWN)  # set GP16 as digital input pin for PIR motion sensor

while True:
    if pir.value(): #when PIR detects motion 
        print("Intruder is detected!")  
        buzzer.low() # make buzzer alarm
        buzzer.high() #close buzzer alarm
        print("No Intruder!")

Step 1: Connect Pico board to one of USB ports in your PC
Step 2: If you haven’t installed Thonny Software or don’t know how to use Thonny IDE, please read lesson 1

Step 3: Now open the Thonny Python IDE, click Run to select MicroPython for Rapsberry Pi Pico as Interpreter :

Also please select the COM port which your Pico board is connected :

After that, click OK to save the setting.

Step 4: Now copy the python code to Thonny window as following:

Step 5: Click the little ► button  ,the save page will pop up as following photo ;

select Raspberry Pi Pico as destination.

Step 6:Name the file as, then click OK

Step 7: Click the little ► button again to run the Python code.

Now you put your hand close to PIR motion sensor, Buzzer will alarm and Shell will show “Intruder is detected”.
Now you remove your hand from PIR motion sensor, Buzzer will stop alarm and Shell will show ” No Intruder”.

After the operation is complete, press Ctrl+C to end the command.

Learn More about parts SKU:2021005900

No. Picture Product Name Link
1 Raspberry Pi Pico Board
2 Servo motor
3 Infrared Sensor Module
4 RFID Module and card
5 Push Buttons and Hats
6 LED(6 x White, 6 x Red, 6 x Yellow, 6x Green)
7 Servo motor
8 Piezo Buzzer Module
9 I2C LCD Display(16×2)
10 Philips Screwdriver
11 Solderless Prototype Breadboard
12 Potentionmeter (10K adjustable resistor)
13 40Pin M to M Jumper Wires
14 20Pin M to F Jumper wires 15cm