2.1.5 Tilt Switch¶
Introduction¶
This is a ball tilt-switch with a metal ball inside. It is used to detect inclinations of a small angle.
Required Components¶
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 |
---|---|---|
Raphael Kit |
337 |
You can also buy them separately from the links below.
COMPONENT INTRODUCTION |
PURCHASE LINK |
---|---|
- |
Schematic Diagram¶
Experimental Procedures¶
Step 1: Build the circuit.
Step 2: Change directory.
cd ~/raphael-kit/python/
Step 3: Run.
sudo python3 2.1.5_Tilt.py
Place the tilt vertically, and the green LED will turns on. If you tilt it, “Tilt!” will be printed on the screen and the red LED will turns on. Place it vertically again, and the green LED will lights on.
Code
Note
You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like raphael-kit/python
. After modifying the code, you can run it directly to see the effect.
import RPi.GPIO as GPIO
TiltPin = 17
Gpin = 27
Rpin = 22
def setup():
GPIO.setmode(GPIO.BCM) # Numbers GPIOs by physical location
GPIO.setup(Gpin, GPIO.OUT) # Set Green Led Pin mode to output
GPIO.setup(Rpin, GPIO.OUT) # Set Red Led Pin mode to output
GPIO.setup(TiltPin, GPIO.IN, pull_up_down=GPIO.PUD_UP) # Set BtnPin's mode is input, and pull up to high level(3.3V)
GPIO.add_event_detect(TiltPin, GPIO.BOTH, callback=detect, bouncetime=200)
def Led(x):
if x == 0:
GPIO.output(Rpin, 1)
GPIO.output(Gpin, 0)
if x == 1:
GPIO.output(Rpin, 0)
GPIO.output(Gpin, 1)
def Print(x):
if x == 0:
print (' *************')
print (' * Tilt! *')
print (' *************')
def detect(chn):
Led(GPIO.input(TiltPin))
Print(GPIO.input(TiltPin))
def loop():
while True:
pass
def destroy():
GPIO.output(Gpin, GPIO.HIGH) # Green led off
GPIO.output(Rpin, GPIO.HIGH) # Red led off
GPIO.cleanup() # Release resource
if __name__ == '__main__': # Program start from here
setup()
try:
loop()
except KeyboardInterrupt: # When 'Ctrl+C' is pressed, the program destroy() will be executed.
destroy()
Code Explanation
GPIO.add_event_detect(TiltPin, GPIO.BOTH, callback=detect, bouncetime=200)
Set up a detect on TiltPin, and callback function to detect.
def Led(x):
if x == 0:
GPIO.output(Rpin, 1)
GPIO.output(Gpin, 0)
if x == 1:
GPIO.output(Rpin, 0)
GPIO.output(Gpin, 1)
Define a function Led() to turn the two LEDs on or off. If x=0, the red LED lights up; otherwise, the green LED will be lit.
def Print(x):
if x == 0:
print (' *************')
print (' * Tilt! *')
print (' *************')
Create a function, Print() to print the characters above on the screen.
def detect(chn):
Led(GPIO.input(TiltPin))
Print(GPIO.input(TiltPin))
Define a callback function for tilt callback. Get the read value of the tilt switch then the function Led() controls the turning on or off of the two LEDs that is depended on the read value of the tilt switch.