Raspberry Pi: Push-button + Two(2) LEDs that Toggle
This project is about adding an additional LED light to the Raspberry Pi: Push-button + One(1) LED post, and having the push-button toggle the LED lights. I used one red and one blue LED.
The desired result, toggle on/off of the two LEDs with the push of a button; if the red light is on then the blue is off, and vice versa.
With this project, I learned I need to have a better understanding around detecting events with the GPIO. I found myself modifying “bouncetime” to achieve the desired result, but it is not optimal.
With the code below, there are times when the lights do not toggle or the light remains on.
Any ideas what I am doing wrong? Let me know in the comment section below.
#!/usr/bin/env python
import RPi.GPIO as GPIO
import time
def on_callback(channel):
GPIO.output(channel, GPIO.input(4))
def off_callback(channel):
GPIO.output(channel, False)
GPIO.setmode(GPIO.BCM)
RED_LED = 25
BLUE_LED = 24
SWITCH_IN = 4
GPIO.setup(SWITCH_IN, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
GPIO.setup(RED_LED, GPIO.OUT, initial=GPIO.LOW)
GPIO.setup(BLUE_LED, GPIO.OUT, initial=GPIO.LOW)
GPIO.add_event_detect(SWITCH_IN, GPIO.RISING, bouncetime=900)
led = BLUE_LED
nled = RED_LED
run = 1
while (run != 0):
try:
if GPIO.event_detected(4):
print led
led = BLUE_LED if (led == RED_LED) else RED_LED
nled = RED_LED if (nled == BLUE_LED) else BLUE_LED
on_callback(led)
off_callback(nled)
pass
except KeyboardInterrupt:
run = 0
GPIO.cleanup()
print 'KeyboardInterrupt caught'
break
GPIO.cleanup()
print 'EXITED!'Also available here, raspi-push-button-led-toggle.
