硬体規格

輕觸開關圖片如下所示

共有四個腳位，但只有二個引腳。內凹相對的那組是直接連通的，如下圖所示，沒按下時，13相連，24相連。

當按下時，12及34才會相連。放開時就會斷開。

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線路接法

先供應 3.3V 電壓 (樹莓派腳位1) 給輕觸開關 (腳2) ，但電源跟開關之間要加一顆10KΩ電阻，然後輕觸開關腳 4 再接 1KΩ電阻，再接入GPIO 進行偵測是否開關有按下，最後 GND 接在輕觸開關腳位 3。如下圖所示。

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測試程式

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觸發Led

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程式碼

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import RPi.GPIO as gpio
import time
WAIT_TIME=200
led17 = 17
touch_key=18
ledOn=False
def led(data):
    global ledOn
    ledOn = not ledOn
    if ledOn:
        gpio.output(led17, gpio.HIGH)
    else:
        gpio.output(led17, gpio.LOW)
def init(callback):
    gpio.setwarnings(False)
    gpio.setmode(gpio.BCM)
    gpio.setup(led17, gpio.OUT)
    gpio.output(led17, gpio.LOW)    
    gpio.setup(touch_key, gpio.IN)
    gpio.add_event_detect(touch_key, gpio.RISING, callback=callback,bouncetime=WAIT_TIME)#放開
    #gpio.add_event_detect(touch_key, gpio.FALLING, callback=callback,bouncetime=WAIT_TIME)#按下
def destroy():
    try:
        gpio.remove_event_detect(touch_key)
        gpio.cleanup()
    except Exception as e :
        print(f"destroy fail:{e}")
if __name__=='__main__':
    try:
        init(led)        
        while True:
            time.sleep(1)
    except:
        destroy()

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執行緒

若要變換 Led，則需使用執行緒。

本範例按一下按鈕，三個 Led 依順序切換，再按一下則全部關掉，完整程式碼如下。

import RPi.GPIO as gpio
import time
import threading
WAIT_TIME=200
led18 = 13
led23 = 19
led24 = 26
touch_key=17
ledOn=False
def led(data):
    global ledOn
    ledOn = not ledOn
    print("Thomas", ledOn)
    if ledOn:
        t=threading.Thread(target=runnable)
        t.start()
    else:
        gpio.output(led18, gpio.LOW)
        gpio.output(led23, gpio.LOW)
        gpio.output(led24, gpio.LOW)
def runnable():
    while ledOn:
        gpio.output(led18, gpio.HIGH)
        time.sleep(0.05)
        gpio.output(led18, gpio.LOW)
        time.sleep(0.01)
        gpio.output(led23, gpio.HIGH)
        time.sleep(0.05)
        gpio.output(led23, gpio.LOW)
        time.sleep(0.01)
        gpio.output(led24, gpio.HIGH)
        time.sleep(0.05)
        gpio.output(led24, gpio.LOW)
        time.sleep(0.01)

        gpio.output(led24, gpio.HIGH)
        time.sleep(0.1)
        gpio.output(led24, gpio.LOW)
        time.sleep(0.01)
        gpio.output(led23, gpio.HIGH)
        time.sleep(0.1)
        gpio.output(led23, gpio.LOW)
        time.sleep(0.01)
        gpio.output(led18, gpio.HIGH)
        time.sleep(0.1)
        gpio.output(led18, gpio.LOW)
        time.sleep(0.01)

def init(callback):
    gpio.setwarnings(False)
    gpio.setmode(gpio.BCM)
    gpio.setup(led18, gpio.OUT)
    gpio.output(led18, gpio.LOW)
    gpio.setup(led23, gpio.OUT)
    gpio.output(led23, gpio.LOW)
    gpio.setup(led24, gpio.OUT)
    gpio.output(led24, gpio.LOW)    
    gpio.setup(touch_key, gpio.IN)
    gpio.add_event_detect(touch_key, gpio.RISING, callback=callback,bouncetime=WAIT_TIME)#放開
    #gpio.add_event_detect(touch_key, gpio.FALLING, callback=callback,bouncetime=WAIT_TIME)#按下
def destroy():
    try:
        gpio.remove_event_detect(touch_key)
        gpio.cleanup()
    except Exception as e :
        print(f"destroy fail:{e}")
if __name__=='__main__':
    try:
        init(led)        
        while True:
            time.sleep(1)
    except:
        destroy()

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