hello,
I am trying to count reluctor teeth with a hall effect sensor. I need the system active when "speedPin" reads over 433counts/hz? and the system deactivated when "speedPin" reads less than 433.
The code works "as is" without the interrupt function. Now I am attempting to add a "anti-stall" function.
The more I research frequency counting/pulse counting, the farther I get from where I want to be.
This is my first UNO project.
Here is what I have so far - minus frequency counting
Thanks,
```
//Torque converter control module v1.2
//60% duty cycle, 30.0hz, mech. pushbutton On/Off switch
//Debounce'd switch
//speedPin = master switch (<433 counts = system disabled, = >433 counts system enabled)
int switchPin = 3;
int outPin = 9;
int speedPin = 1;
int outLevel = 0; //duty cycle 0-255
boolean lastButton = LOW;
boolean currentButton = LOW;
void setup()
{
TCCR1B = TCCR1B & B11111000 | B00000101; // for PWM frequency of 30.64 Hz
pinMode (switchPin, INPUT);
pinMode (outPin, OUTPUT);
pinMode (speedPin, INPUT);
}
boolean debounce (boolean last) //debounce function start
{
boolean current = digitalRead(switchPin);
if (last != current)
{
delay (5); //debounce delay in ms
current = digitalRead(switchPin);
}
return current; //debounce function end
}
void loop()
{
currentButton = debounce(lastButton);
if (lastButton == LOW && currentButton == HIGH)
{
outLevel = outLevel + 153; //duty cycle set to 60% (starts @ "0" then increases by 153 every button press)
}
lastButton = currentButton;
if (outLevel > 255) outLevel = 0; //sets outLevel back to "0" if 255 is exceeded
analogWrite(outPin, outLevel);
}```
If you just want to determine the frequency, not RPM, then you should be able to reuse this code I copied out of my tachometer.
This uses the pulsein function and in my testing it has given quite accurate results.
Just set the minimum expected frequency, which maybe lower than 1 but not 0. I havent tested that
You'll have to work your inputs and outputs into it.
I've found it's handy to debounce your switches externally so you dont need a delay or additional complex code. A capacitor and resistor are usually enough.
I searched far and wide for tachometer and speedometer programs and tested many of the methods I found, including such as using interrupts. This method here seemed most stable and worked best for me.
Bonus is no tricky timers or interrupts - pulsein and tiny bit of maths does everything.
This may not compile as-is since I pulled it out of a bigger program, but it should be easy to get going with your requirements.
// Frequency counter
// uses microseconds via the pulsein functions
//
// Does not use interupts
//
// There will be some slight blocking delay
// as pulsein waits for very slow pulses
//
// pulsein timeout is calculated
// from the lowest expected frquency
//==================================================
// Set this to the minimum expected frequency in Hz
float Min_Freq = 10
//==================================================
// RPM frequency input pin
const int speedPin = 1;
// RPM variables
unsigned long hightime, lowtime, pulsein_timeout;
float freq, period;
//---------------------------------------------------
void setup() {
// Digital inputs
pinMode(speedPin, INPUT);
// Maximum time for pulseIn to wait in microseconds
// Use the period of the lowest expected frequency, and double it
if (Min_Freq < 1) Min_Freq = 1;
pulsein_timeout = 1000000.0 / Min_Freq * 2.0;
} // End void setup
//---------------------------------------------------
void loop() {
hightime = pulseIn(speedPin, HIGH, pulsein_timeout);
lowtime = pulseIn(speedPin, LOW, pulsein_timeout);
period = hightime + lowtime;
freq = 1000000.0 / period;
// Limit the frequency range if necessary
// to remove erroneous readings
freq = constrain(freq, Min_Freq, 2000);
// Your stuff here
// at this point freq is a float
// so convert to an interger or whatever required
if (freq >= 433) {do something};
else {some other thing};
// maybe display the freq
} // End void loop
//---------------------------------------------------
