在电子产品和 Arduino 方面，我是新手——所以最好的方法就是玩弄它，对吧？
我已经开始了一个利用 LDR（光密度电阻器）的小项目，并想用它来计算光束被阻挡或关闭的频率。
出于调试目的，我设置了一个以定义频率（5 Hz 等）闪烁的小 LED，并使用 LCD 显示输出。
我的右上角有问题......它似乎执行错误。它的目的是显示注册的频率，但在调试时我已将其设置为以 5 秒（5,000 毫秒）的间隔显示计数。但无论我设置什么频率，它似乎都是最大值（当我让它显示正确的数字 [5 sec x 5 Hz = 25] 我将除以时间间隔并以 Hz 为单位得到结果）。它还显示 24.0 for 9 Hz 等。
我也有这个：YouTube 视频
...但一开始的一些摸索导致 LED 移动了一点，所以它计数错误。但最终它“有效”..但 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“干净”的代码（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;
}
}
这段代码不能解决我的问题，但更容易阅读。