Question

对于电子产品和Arduino来说，我是个新手 - 所以最好的方法就是玩它吧，对吗？

我已经开始了一个利用LDR（光密度电阻）的小项目，并希望用它来计算光束被阻挡或关闭的频率。

出于调试目的，我设置了一个小LED，以指定的频率（5 Hz等）闪烁，并使用LCD显示输出。

Display

我的右上角有问题......似乎它的表现错误。它的目的是显示注册频率，但在调试时我将其设置为以5秒（5,000毫秒）的间隔显示计数。但是无论我设定的是什么频率，它都显示24是最大的（当我得到它以显示正确的数字[5秒x 5 Hz = 25]时，我将除以时间间隔并以Hz为单位得到结果）。它还显示24.0为9 Hz等。

我也有：YouTube video

...但是一开始的一些摸索导致LED移动了一点，所以它算错了。但最终它会起作用＃34;但是24.0保持不变

这是我的代码：

#include <LiquidCrystal.h>

LiquidCrystal lcd(7, 8, 9, 10, 11 , 12);
int booBlocked = 0;
int counter = 0;
int checkValue = counter + 1;

int ledPin = 3;                // LED connected to digital pin 3
int value = LOW;                // previous value of the LED
long previousMillis = 0;        // will store last time LED was updated
long freqency = 5; // Hz (1/sec)
long thousand = 1000;
long interval = thousand / freqency; // milliseconds
//long interval = 59;           // interval at which to blink (milliseconds)

int tValue = 0; // Threshold value used for counting (are calibrated in the beginning)
long pMillis = 0;
long inter = 5000;
int pCount = 0;
float freq = 0;  // Calculated blink frequency...

void setup() { 
  lcd.begin(16, 2);
  lcd.setCursor(0,1);  lcd.print(interval);
  lcd.setCursor(4,1);  lcd.print("ms");

  pinMode(ledPin, OUTPUT);      // sets the digital pin as output 

  lcd.setCursor(0,0);  lcd.print(freqency);
  lcd.setCursor(4,0);  lcd.print("Hz");
}

void loop() {
  // Print LDR sensor value to the display  
  int sensorValue = analogRead(A0);
  lcd.setCursor(7,1);
  lcd.print(sensorValue);
  delay(100);

  if (millis() > 5000){
    doCount(sensorValue);
    updateFreq();
    lcd.setCursor(7+5,0);
    lcd.print(freq);
  } else {
    setThresholdValue(sensorValue);
    lcd.setCursor(7+5,1);
    lcd.print(tValue);
  }

 // LED BLINK
  if (millis() - previousMillis > interval) {
    previousMillis = millis();   // remember the last time we blinked the LED
    // if the LED is off turn it on and vice-versa.
    if (value == LOW)
      value = HIGH;
    else
      value = LOW;
    digitalWrite(ledPin, value);
  }    
}

void updateFreq(){
 long now = millis();
 long t = now - pMillis;
 if (t >= 10000) {
   freq = (float) (counter - pCount);
   //freq = ((float) (counter - pCount)) / (float) 10.0;
   pMillis = now;   // remember the last time we blinked the LED
   pCount = counter;
  } 
}

void setThresholdValue(int sensorValue){
  if (sensorValue > int(tValue/0.90)){
    tValue = int (sensorValue*0.90);
  }
}

void doCount(int sensorValue){
    // Count stuff
  if (sensorValue < tValue){
    booBlocked = 1;
    //lcd.setCursor(0,0);
    //lcd.print("Blocked");
  } else {
    booBlocked = 0;
    //lcd.setCursor(0,0);
    //lcd.print("       ");    
  }

  if (booBlocked == 1) {
   if (counter != checkValue){
    counter = counter + 1;
    lcd.setCursor(7,0);
    lcd.print(counter);
   }   
  } else {
   if (counter == checkValue){
    checkValue = checkValue + 1;
     }
   }
}

更新

更多＆＃34;清洁＆＃34;代码（请参阅我自己的答案）

#include <LiquidCrystal.h>
// Initiate the LCD display
LiquidCrystal lcd(7, 8, 9, 10, 11 , 12); // see setup at http://lassenorfeldt.weebly.com/1/post/2013/02/ardunio-lcd.html
long updateInterval = 150;                // ms
long updateTime = 0;

// Declare the pins
int ledPin = 3;                       // LED connected to digital pin 3

// LED setup
int value = LOW;                      // previous value of the LED
long previousMillis = 0;              // will store last time LED was updated 
long freqency = 16;                   // Hz (1/sec)
long thousand = 1000;
long blinkInterval = thousand / freqency;  // milliseconds

//// LDR counter variables ////
// Counting vars
static int counter = 0;
int booBlocked = 0;
int checkValue = counter + 1;
// Calibration vars
long onBootCalibrationTime = 5000;     // time [time] to use for calibration when the system is booted
static int threshold = 0;              // Value used for counting (calibrated in the beginning)
float cutValue = 0.90;                 // Procent value used to allow jitting in the max signal without counting.

// Frequency vars
float freq = 0;                        // Calculated blink frequency...
long frequencyInterval = 5000;        // time [ms] 
long pMillis = 0;
int pCount = 0;



void setup() {
  // Setup the pins
  pinMode(ledPin, OUTPUT);      // sets the digital pin as output 

  // display static values
  lcd.begin(16, 2);
  lcd.setCursor(0,0);  lcd.print(freqency);
  lcd.setCursor(4,0);  lcd.print("Hz");
  lcd.setCursor(0,1);  lcd.print(blinkInterval);
  lcd.setCursor(4,1);  lcd.print("ms");

  // Setup that allows loggin
  Serial.begin(9600);  // Allows to get a readout from Putty (windows 7)
}

void loop() {  
  long time = millis();
  int sensorValue = analogRead(A0);

  // Blink the LED
  blinkLED(time);

  // Calibrate or Count (AND calculate the frequency) via the LDR
  if (time < onBootCalibrationTime){
    setThresholdValue(sensorValue);
  } else {    
    doCount(sensorValue);
    updateFreq(time);
  }


  // Update the LCD
  if (time > updateTime){
    updateTime += updateInterval;  // set the next time to update the LCD

   // Display the sensor value
    lcd.setCursor(7,1);  lcd.print(sensorValue);
   // Display the threshold value used to determined if blocked or not
    lcd.setCursor(7+5,1);  lcd.print(threshold);
   // Display the count
    lcd.setCursor(7,0);
    lcd.print(counter);
   // Display the calculated frequency
    lcd.setCursor(7+5,0);  lcd.print(freq);   
  }  
}

void blinkLED(long t){
  if (t - previousMillis > blinkInterval) {
    previousMillis = t;   // remember the last time we blinked the LED
    // if the LED is off turn it on and vice-versa.
    if (value == LOW)
      value = HIGH;
    else
      value = LOW;
    digitalWrite(ledPin, value);
  }
}

void setThresholdValue(int sValue){
  if (sValue > int(threshold/cutValue)){
    threshold = int (sValue*cutValue);
  }
}

void doCount(int sValue){
  if (sValue < threshold){
    booBlocked = 1;
  } else {
    booBlocked = 0;  
  }

  if (booBlocked == 1) {
   if (counter != checkValue){
    counter = counter + 1;
   }   
  } else {
   if (counter == checkValue){
    checkValue = checkValue + 1;
     }
   }
}

void updateFreq(long t){
 long inter = t - pMillis;
 if (inter >= frequencyInterval) {
   freq = (counter - pCount) / (float) (inter/1000);
   pMillis = t;           // remember the last time we blinked the LED
   pCount = counter;
  } 
}

此代码不能解决我的问题，但更容易阅读。

Answer 1

您的计划存在的问题是，光密度电阻会吸收周围的所有环境光，因此对环境非常敏感。

还有其他项目希望吗？这个看起来像是一种工程学习经验，而不是编码经验。

您是否想过电机项目？就个人而言，我更喜欢家庭自动化，但电机项目几乎立即有所回报。

Answer 2

我建议您按照以下方式重新编写doCount()函数，以使事情变得更简单，更容易理解：

void doCount(int sensorValue){

  static int previousState;
  int currentState;

  if ( previousState == 0 ) {
      currentState = sensorValue > upperThreshold;
  } else {
      currentState = sensorValue > lowerThreshold;
  }

  if ( previousState != 0 ) {
      if ( currentState == 0 ) {
          counter++;
      }
  }

  previousState = currentState;

}

让lowerThreshold和upperThreshold分别为前tValue的90％和110％，并且你有一个迟滞来平滑对嘈杂ADC读取的反应-outs。

Answer 3

我想我发现了其中一个错误..我使用delay()导致了一些麻烦..

我清理了代码：

#include <LiquidCrystal.h>
// Initiate the LCD display
LiquidCrystal lcd(7, 8, 9, 10, 11 , 12); // see setup at http://lassenorfeldt.weebly.com/1/post/2013/02/ardunio-lcd.html
long updateInterval = 150;                // ms
long updateTime = 0;

// Declare the pins
int ledPin = 3;                       // LED connected to digital pin 3

// LED setup
int value = LOW;                      // previous value of the LED
long previousMillis = 0;              // will store last time LED was updated 
long freqency = 16;                   // Hz (1/sec)
long thousand = 1000;
long blinkInterval = thousand / freqency;  // milliseconds

//// LDR counter variables ////
// Counting vars
static int counter = 0;
int booBlocked = 0;
int checkValue = counter + 1;
// Calibration vars
long onBootCalibrationTime = 5000;     // time [time] to use for calibration when the system is booted
static int threshold = 0;              // Value used for counting (calibrated in the beginning)
float cutValue = 0.90;                 // Procent value used to allow jitting in the max signal without counting.

// Frequency vars
float freq = 0;                        // Calculated blink frequency...
long frequencyInterval = 5000;        // time [ms] 
long pMillis = 0;
int pCount = 0;



void setup() {
  // Setup the pins
  pinMode(ledPin, OUTPUT);      // sets the digital pin as output 

  // display static values
  lcd.begin(16, 2);
  lcd.setCursor(0,0);  lcd.print(freqency);
  lcd.setCursor(4,0);  lcd.print("Hz");
  lcd.setCursor(0,1);  lcd.print(blinkInterval);
  lcd.setCursor(4,1);  lcd.print("ms");

  // Setup that allows loggin
  Serial.begin(9600);  // Allows to get a readout from Putty (windows 7)
}

void loop() {  
  long time = millis();
  int sensorValue = analogRead(A0);

  // Blink the LED
  blinkLED(time);

  // Calibrate or Count (AND calculate the frequency) via the LDR
  if (time < onBootCalibrationTime){
    setThresholdValue(sensorValue);
  } else {    
    doCount(sensorValue);
    updateFreq(time);
  }


  // Update the LCD
  if (time > updateTime){
    updateTime += updateInterval;  // set the next time to update the LCD

   // Display the sensor value
    lcd.setCursor(7,1);  lcd.print(sensorValue);
   // Display the threshold value used to determined if blocked or not
    lcd.setCursor(7+5,1);  lcd.print(threshold);
   // Display the count
    lcd.setCursor(7,0);
    lcd.print(counter);
   // Display the calculated frequency
    lcd.setCursor(7+5,0);  lcd.print(freq);   
  }  
}

void blinkLED(long t){
  if (t - previousMillis > blinkInterval) {
    previousMillis = t;   // remember the last time we blinked the LED
    // if the LED is off turn it on and vice-versa.
    if (value == LOW)
      value = HIGH;
    else
      value = LOW;
    digitalWrite(ledPin, value);
  }
}

void setThresholdValue(int sValue){
  if (sValue > int(threshold/cutValue)){
    threshold = int (sValue*cutValue);
  }
}

void doCount(int sValue){
  if (sValue < threshold){
    booBlocked = 1;
  } else {
    booBlocked = 0;  
  }

  if (booBlocked == 1) {
   if (counter != checkValue){
    counter = counter + 1;
   }   
  } else {
   if (counter == checkValue){
    checkValue = checkValue + 1;
     }
   }
}

void updateFreq(long t){
 long inter = t - pMillis;
 if (inter >= frequencyInterval) {
   freq = (counter - pCount) / (float) (inter/1000);
   pMillis = t;           // remember the last time we blinked the LED
   pCount = counter;
  } 
}

它不像我希望的那样精确......但我相信这可能是由于我闪烁LED的方式。

我还发现float cutValue = 0.90;有影响......将标准降低到0.85会降低计算频率。??

Answer 4

在Albert非常友好地帮助我使用他的真棒FreqPeriodCounter library

后，我完全改变了代码

我还添加了一个电位计来控制频率

这是我的代码：

#include <FreqPeriodCounter.h>
#include <LiquidCrystal.h>

// FrequencyCounter vars
const byte counterPin = 3;  // Pin connected to the LDR
const byte counterInterrupt = 1; // = pin 3
FreqPeriodCounter counter(counterPin, micros, 0);

// LCD vars
LiquidCrystal lcd(7, 8, 9, 10, 11 , 12); // see setup at http://lassenorfeldt.weebly.com/1/post/2013/02/ardunio-lcd.html
long updateInterval = 200;                // ms
long updateTime = 0;

// LED vars
int ledPin = 5;                       // LED connected to digital pin 3
int value = LOW;                      // previous value of the LED
float previousMillis = 0;              // will store last time LED was updated 
static float freqency;                   // Hz (1/sec)
static float pfreqency;
static float blinkInterval;  // milliseconds

boolean logging = true;              // Logging by sending to serial

// Use potentiometer to control LED frequency
int potPin = 5;    // select the input pin for the potentiometer
int val = 0;       // variable to store the value coming from the sensor

void setup(void){ 
  // Setup the pins
  pinMode(ledPin, OUTPUT);      // sets the digital pin as output 

  val = analogRead(potPin);
  freqency = map(val, 0, 1023, 0, 25);                   // Hz (1/sec)
  pfreqency = freqency;
  blinkInterval = 1000 / (freqency*2);                  // milliseconds


  // LCD display static values
  lcd.begin(16, 2);
  lcd.setCursor(0,0);  lcd.print(freqency);
  lcd.setCursor(4,0);  lcd.print("Hz");
  lcd.setCursor(14,0);  lcd.print("Hz");
  lcd.setCursor(0,1);  lcd.print(blinkInterval);
  lcd.setCursor(4,1);  lcd.print("ms");

  //   
  attachInterrupt(counterInterrupt, counterISR, CHANGE);

  // Logging
  if (logging) {Serial.begin(9600);}
}

void loop(void){ 
  // Loop vars
  float time = (float) millis();
  float freq = (float) counter.hertz(10)/10.0;

  // Blink the LED
  blinkLED(time);


  if (logging) {
    if(counter.ready()) Serial.println(counter.hertz(100));
  }

  // Update the LCD
  if (time > updateTime){
    updateTime += updateInterval;  // set the next time to update the LCD
    lcdNicePrint(7+3, 0, freq); lcd.setCursor(14,0);  lcd.print("Hz"); 
    val = analogRead(potPin);
    freqency = map(val, 0, 1023, 1, 30);

    if (freqency != pfreqency){
      pfreqency = freqency;      
      blinkInterval = 1000 / (freqency*2);                  // milliseconds

      lcdNicePrint(0,0, freqency);  lcd.setCursor(4,0);  lcd.print("Hz");
      lcd.setCursor(0,1);  lcd.print(blinkInterval);
      lcd.setCursor(4,1);  lcd.print("ms");
    }
  }
}

void lcdNicePrint(int column, int row, float value){
  lcd.setCursor(column, row);  lcd.print("00");
  if (value < 10) {lcd.setCursor(column+1, row);  lcd.print(value);}
  else {lcd.setCursor(column, row);  lcd.print(value);}
}  

void blinkLED(long t){

  if (t - previousMillis > blinkInterval) {
    previousMillis = t;   // remember the last time we blinked the LED
    // if the LED is off turn it on and vice-versa.
    if (value == LOW)
      value = HIGH;
    else
      value = LOW;
    digitalWrite(ledPin, value);
  }
}

void counterISR()
{ counter.poll();
}

Arduino计算频率 - 我在这里做错了什么？

更新

4 个答案: