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2.6 Tilt It!

In this lesson, we’ll learn how to use a tilt switch with the Raspberry Pi Pico 2 to detect changes in orientation. A tilt switch is a simple device that can sense whether it is upright or tilted, making it useful for applications like motion detection, orientation sensing, or as a trigger based on position.

What You’ll Need

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Newton Lab Kit	450+	Newton Lab Kit

You can also buy them separately from the links below.

SN	COMPONENT	QUANTITY	LINK
1	Raspberry Pi Pico 2	1	BUY
2	Micro USB Cable	1
3	Breadboard	1	BUY
4	Jumper Wires	Several	BUY
5	Resistor	1(10KΩ)	BUY
6	Tilt Switch	1

Circuit Diagram

• When Upright (Switch Closed):

  • The tilt switch connects 3.3V directly to GP14.

  • The GPIO pin reads HIGH (1).

• When Tilted (Switch Open):

  • The tilt switch disconnects 3.3V from GP14.

  • The pull-down resistor pulls GP14 to GND.

  • The GPIO pin reads LOW (0).

Wiring

Writing the Code

We’ll write a simple MicroPython program that detects the state of the tilt switch and prints a message when the switch is tilted.

Note

• Open the 2.6_tilt_switch.py from newton-lab-kit/micropython or copy the code into Thonny, then click “Run” or press F5.

• Ensure the correct interpreter is selected: MicroPython (Raspberry Pi Pico).COMxx.

import machine
import utime

# Initialize GP14 as an input pin
tilt_switch = machine.Pin(14, machine.Pin.IN)

while True:
    if tilt_switch.value() == 0:
        print("Tilt detected!")
        utime.sleep(1)  # Delay to avoid multiple rapid detections

When the code is running, you will observe the following phenomenon:

• Keep the tilt switch upright; no message should appear.

• Tilt the breadboard or switch; “Tilt detected!” should appear in the console.

Understanding the Code

1. Import Modules:

   • import machine: Gives us access to the hardware components.

   • import utime: Allows us to use time-related functions.

2. Initialize the Tilt Switch Pin:

   • tilt_switch = machine.Pin(14, machine.Pin.IN): Sets up GP14 as an input pin.

3. Main Loop:

   • while True: Creates an infinite loop to continuously check the tilt switch state.

   • if tilt_switch.value() == 0: Checks if the GPIO pin reads LOW (0), indicating the switch is tilted.

   • print("Tilt detected!"): Outputs a message when the tilt is detected.

   • utime.sleep(1): Adds a 1-second delay to debounce the switch and prevent multiple detections.

Alternative Wiring: Using Internal Pull-Down Resistor

The Raspberry Pi Pico 2 allows us to enable internal pull-up or pull-down resistors, eliminating the need for an external resistor.

import machine
import utime

# Initialize GP14 as an input pin with internal pull-down resistor
tilt_switch = machine.Pin(14, machine.Pin.IN, machine.Pin.PULL_DOWN)

while True:
    if tilt_switch.value() == 1:
        print("Tilt detected!")
        utime.sleep(1)

By enabling the internal pull-down resistor (machine.Pin.PULL_DOWN), the GPIO pin defaults to LOW when no voltage is applied. When the tilt switch is upright (closed), it connects 3.3V to GP14, and the pin reads HIGH (1).

Practical Applications

• Orientation Detection: Determine if a device is upright or tilted.

• Motion-Triggered Events: Activate alarms, notifications, or actions when movement is detected.

• Interactive Projects: Use as an input to control games or installations that respond to tilting.

Experimenting Further

• Add an LED Indicator:

Connect an LED to another GPIO pin (e.g., GP15) with a suitable resistor. Modify the code to light up the LED when a tilt is detected.

import machine
import utime

tilt_switch = machine.Pin(14, machine.Pin.IN, machine.Pin.PULL_DOWN)
led = machine.Pin(15, machine.Pin.OUT)

while True:
    if tilt_switch.value() == 1:
        print("Tilt detected!")
        led.value(1)  # Turn on the LED
        utime.sleep(1)
    else:
        led.value(0)  # Turn off the LED

• Use with Other Sensors:

  Combine the tilt switch with other sensors like buttons or light sensors for more complex interactions.

Conclusion

By incorporating a tilt switch into your Raspberry Pi Pico 2 projects, you can add a new dimension of interactivity based on orientation and movement. Understanding how to read digital inputs from sensors like the tilt switch expands your ability to create dynamic and responsive electronics.