User Manual

digitalWrite (LedPin, HIGH) in while: close the LED. if (digitalRead (ButtonPin) == 0:

check whether the button has been pressed. Execute digitalWrite(LedPin, LOW) when

pressed to light up LED.

Press Ctrl+X to exit, if you have modified the code, there will be a prompt asking w hether to

save the changes or not. Type in Y (save) or N (don’t save). Then press Enter to exit. Repeat

Step 3 and Step 4 to see the effect after modifying.

For Python users:

Step 2: Open the code file

cd /home/pi/SunFounder_Super_Kit_V3.0_for_Raspberry_Pi/Python

Step 3: Run the code

sudo python 02_buttonControlLed.py

Step 4: Check the code

nano 02_buttonControlLed.py

Code Explanation

LedPin = 17 # Set #17 as LED pin

BtnPin = 18 # Set #18 as button pin

# Set up a falling detect on BtnPin, and callback function to swled

GPIO.add_event_detect(BtnPin, GPIO.FALLING, callback=swLED)

# Define a callback function for button callback, execute the function after the

callback of the interrupt.

def swLed(ev=None):

global Led_status

# Switch Led status (on-->off; off-->on)

Led_status = not Led_status

GPIO.output(LedPin, Led_status)

if Led_status:

print 'LED OFF...'

else:

print '...LED ON'

Now, press the button, and the LED will light up; press the button again, and the LED will go

out. At the same time, the state of the LED will be printed on the screen.

SunFounder