Question

我想关掉我的Raspberry Pi的LED。

我尝试修改文件echo none >/sys/class/leds/led0/trigger，但没有任何改变。

这可能吗？

Answer 1

根据Raspberry Pi论坛：

Answer 2

RaspberryMediaCenter:/sys/class/leds # echo 0 >/sys/class/leds/led1/brightness
RaspberryMediaCenter:/sys/class/leds # echo 0 >/sys/class/leds/led0/brightness

led0绿色

led1红色

Answer 3

根据您所说的LED，看起来不可能。

有关更多信息，请阅读How can I turn the lights off on my pi?（这也是询问RPi问题的好地方）

Answer 4

我意识到这是一个老问题。但是，这是我在谷歌搜索结果中的第一个，它对我的Raspberry Pi2 B +不起作用。对于像我这样现在发现这一点的人来说，http://www.jeffgeerling.com/blogs/jeff-geerling/controlling-pwr-act-leds-raspberry-pi的技术确实有效。

Answer 5

在Pi上，您可以通过编辑位于以下位置的文件来控制2 Leds（红色和绿色）。

//word to solve
String keyword = "stackoverflow";
int lettersLeft = keyword.length();
//solved word to remove guessed letters from
String solved;

int lives;
int maxLives;

//what has been guessed so far
String solution;
//a lookup of all the letters already pressed
HashMap<Character,Integer> usedLetters = new HashMap<Character,Integer>();

//game status
String status;
boolean gameOn;

//stick figure drawing
PShape hangman;//the empty group
PShape[] hangmanMembers;//each part


void setup(){
  size(100,100,P2D);
  //intialize the group
  hangman = createShape(GROUP);
  hangman.addChild(createShape(LINE,20,100,20,30));
  hangman.addChild(createShape(LINE,20,30,50,30));
  hangman.addChild(createShape(LINE,50,30,50,35));
  hangmanMembers = new PShape[]{createShape(ELLIPSE,50,35,10,10),//head
                               createShape(LINE    ,55,45,55,50),//neck
                               createShape(LINE    ,55,50,55,70),//body
                               createShape(LINE    ,55,50,40,45),//left arm
                               createShape(LINE    ,55,50,80,45),//right arm
                               createShape(LINE    ,55,70,40,90),//left leg
                               createShape(LINE    ,55,70,60,90)//right leg
                              };
  //some people draw a hangman with no neck, other use more parts, make the number of lives dependant on that
  maxLives = hangmanMembers.length;
  lives = maxLives;//set the number of lives left
  //add the dashes
  solved = ""+keyword;
  solution = "";
  status = "";
  for(int i = 0 ; i < lettersLeft; i++) solution += "_";
  usedLetters.clear();
  gameOn = true;
}
//render
void draw(){
  background(127);
  text(solution,10,15);
  text(status,10,25);
  shape(hangman);
}

void keyPressed(){
  //if the game was not won or lost yet
  if(gameOn){
    //check if the key pressed is a letter
    if(Character.isLetter(key)){
      //check if the letter hasn't been used before
      if(!usedLetters.containsKey(key)){
        //if so, add to the list of used letters
        usedLetters.put(key,keyCode);

        //check if the word contains the letter
        int index = keyword.indexOf(key);
        if(index >= 0){
          println(key + " is in " + keyword);

          //remove the found letter from the word
          solved = solved.replaceAll(""+key,""); 
          println("letters left: " + solved);
          //update text for display
          for(int i = 0 ; i < solution.length(); i++){
            if(keyword.charAt(i) == key){
              solution = solution.substring(0,i)+key+solution.substring(i+1);
            }
          }
          //if all letters have been found, we have a winner
          if(solved.isEmpty()) {
            status = "you win!";
            gameOn = false;
          }
        }else{//wrong letter, lose a part
          int livesDiff = maxLives-lives;//work out the number of lives lost (maximum value - current)
          if(livesDiff < maxLives) {//if there still is a shape to display
            hangman.addChild(hangmanMembers[livesDiff]);
          }
          println(livesDiff);
          lives--;
          if(lives <= 0){
            status = "game over!";
            gameOn = false;
          }
        }
      }else{
        println("you've used " + key + " before");
      }
    }
  }else{
    //reset
    setup();
  }
}

例如，当Pi正在访问SD卡时关闭绿色指示灯的通常闪烁，您可以运行（作为管理员）：

/sys/class/leds/led[num]

要打开或关闭一个LED，您可以更改亮度文件的状态（作为管理员）：

echo none > /sys/class/leds/led0/trigger

这是我在Python中非常不优雅的解决方法，可以实际控制状态：

echo 1 > /sys/class/leds/led0/brightness     # turn on
echo 0 > /sys/class/leds/led0/brightness     # turn off

关掉Raspberry Pi的LED

5 个答案: