Új hozzászólás Aktív témák

• #15596 Tomika86 senior tag Aryes #15593

  Új Válasz 2021-06-23 19:57:08 #15596

  Új hozzászólás

  Összes hozzászólása itt Válaszok az összes hozzászólására itt Válaszok erre a hozzászólásra

  Privát üzenet küldése

  

  Tomika86

  senior tag

  válasz Aryes #15593 üzenetére

  Ez a bonyolultabb mérés, ez a hirtelen változásokra van hogy lemegy 0-ra is, meg összevissza ugrál ilyenkor:
  const byte PulsesPerRevolution = 2;
const unsigned long ZeroTimeout = 100000; // For high response time, a good value would be 100000.
// For reading very low RPM, a good value would be 300000.
// Calibration for smoothing RPM:
const byte numReadings = 2; // Number of samples for smoothing. The higher, the more smoothing, but it's going to
// react slower to changes. 1 = no smoothing. Default: 2.
/////////////
// Variables:
/////////////
volatile unsigned long LastTimeWeMeasured; // Stores the last time we measured a pulse so we can calculate the period.
volatile unsigned long PeriodBetweenPulses = ZeroTimeout+1000; // Stores the period between pulses in microseconds.
// It has a big number so it doesn't start with 0 which would be interpreted as a high frequency.
volatile unsigned long PeriodAverage = ZeroTimeout+1000; // Stores the period between pulses in microseconds in total, if we are taking multiple pulses.
// It has a big number so it doesn't start with 0 which would be interpreted as a high frequency.
unsigned long FrequencyRaw; // Calculated frequency, based on the period. This has a lot of extra decimals without the decimal point.
unsigned long FrequencyReal; // Frequency without decimals.
unsigned long RPM; // Raw RPM without any processing.
unsigned int PulseCounter = 1; // Counts the amount of pulse readings we took so we can average multiple pulses before calculating the period.
unsigned long PeriodSum; // Stores the summation of all the periods to do the average.
unsigned long LastTimeCycleMeasure = LastTimeWeMeasured;
unsigned long CurrentMicros = micros();
unsigned int AmountOfReadings = 1;
unsigned int ZeroDebouncingExtra; // Stores the extra value added to the ZeroTimeout to debounce it.
// The ZeroTimeout needs debouncing so when the value is close to the threshold it
// doesn't jump from 0 to the value. This extra value changes the threshold a little
// when we show a 0.
// Variables for smoothing tachometer:
unsigned long readings[numReadings]; // The input.
unsigned long readIndex; // The index of the current reading.
unsigned long total; // The running total.
unsigned long average; // The RPM value after applying the smoothing.

void setup() // Start of setup:
{
Serial.begin(9600); // Begin serial communication.
attachInterrupt(digitalPinToInterrupt(2), Pulse_Event, RISING); // Enable interruption pin 2 when going from LOW to HIGH.
delay(1000); // We sometimes take several readings of the period to average. Since we don't have any readings
// stored we need a high enough value in micros() so if divided is not going to give negative values.
// The delay allows the micros() to be high enough for the first few cycles.
} // End of setup.

void loop() // Start of loop:
{
LastTimeCycleMeasure = LastTimeWeMeasured; // Store the LastTimeWeMeasured in a variable.
CurrentMicros = micros();
if(CurrentMicros < LastTimeCycleMeasure)
{
LastTimeCycleMeasure = CurrentMicros;
}
// Calculate the frequency:
FrequencyRaw = 10000000000 / PeriodAverage; // Calculate the frequency using the period between pulses.
// Detect if pulses stopped or frequency is too low, so we can show 0 Frequency:
if(PeriodBetweenPulses > ZeroTimeout - ZeroDebouncingExtra || CurrentMicros - LastTimeCycleMeasure > ZeroTimeout - ZeroDebouncingExtra)
{ // If the pulses are too far apart that we reached the timeout for zero:
FrequencyRaw = 0; // Set frequency as 0.
ZeroDebouncingExtra = 2000; // Change the threshold a little so it doesn't bounce.
}
else
{
ZeroDebouncingExtra = 0; // Reset the threshold to the normal value so it doesn't bounce.
}

FrequencyReal = FrequencyRaw / 10000; // Get frequency without decimals. This is not used to calculate RPM but we remove the decimals just in case you want to print it.

// Calculate the RPM:
RPM = FrequencyRaw / PulsesPerRevolution * 60; // Frequency divided by amount of pulses per revolution multiply by 60 seconds to get minutes.
RPM = RPM / 10000; // Remove the decimals.
// Smoothing RPM:
total = total - readings[readIndex]; // Advance to the next position in the array.
readings[readIndex] = RPM; // Takes the value that we are going to smooth.
total = total + readings[readIndex]; // Add the reading to the total.
readIndex = readIndex + 1; // Advance to the next position in the array.
if (readIndex >= numReadings) // If we're at the end of the array:
{
readIndex = 0; // Reset array index.
}
average = total / numReadings; // The average value it's the smoothed result.
Serial.print("\nRPM: ");
Serial.print(RPM);
Serial.print("\tTachometer: ");
Serial.println(average);
}

void Pulse_Event() // The interrupt runs this to calculate the period between pulses:
{
PeriodBetweenPulses = micros() - LastTimeWeMeasured; // Current "micros" minus the old "micros" when the last pulse happens.
// This will result with the period (microseconds) between both pulses.
// The way is made, the overflow of the "micros" is not going to cause any issue.
LastTimeWeMeasured = micros(); // Stores the current micros so the next time we have a pulse we would have something to compare with.

if(PulseCounter >= AmountOfReadings) // If counter for amount of readings reach the set limit:
{
PeriodAverage = PeriodSum / AmountOfReadings; // Calculate the final period dividing the sum of all readings by the
// amount of readings to get the average.
PulseCounter = 1; // Reset the counter to start over. The reset value is 1 because its the minimum setting allowed (1 reading).
PeriodSum = PeriodBetweenPulses;
// Remap period to the amount of readings:
int RemapedAmountOfReadings = map(PeriodBetweenPulses, 40000, 5000, 1, 10); // Remap the period range to the reading range.
// 1st value is what are we going to remap. In this case is the PeriodBetweenPulses.
// 2nd value is the period value when we are going to have only 1 reading. The higher it is, the lower RPM has to be to reach 1 reading.
// 3rd value is the period value when we are going to have 10 readings. The higher it is, the lower RPM has to be to reach 10 readings.
// 4th and 5th values are the amount of readings range.
RemapedAmountOfReadings = constrain(RemapedAmountOfReadings, 1, 10); // Constrain the value so it doesn't go below or above the limits.
AmountOfReadings = RemapedAmountOfReadings; // Set amount of readings as the remaped value.
}
else
{
PulseCounter++; // Increase the counter for amount of readings by 1.
PeriodSum = PeriodSum + PeriodBetweenPulses; // Add the periods so later we can average.
}
}

Új hozzászólás Aktív témák