Analog Read how to do it?

Projects Programming
1

This code is correct and works but I need instead of calcFactor change I can do it analog with potentiometer and change to A0 (Analog read) how to do it?

//1986 Porsche 944 Turbo Speedometer Calibrator

//Public Domain

//raw 944 transmission sensor signal must be processed by external schmitt trigger

//Schmitt trigger should bypass filer and pull-up resistor

//Use LM2940-10 with decoupling caps per datasheet to power Arduino in automotive setting

//Arduino Pin 7 supplies modified signal for speedometer

const int debounce = 2500;

const int speedometerPin = 7;

const int sensorPin = 3;

int pulseState = LOW;

volatile unsigned long currentMicros = 0;

volatile unsigned long previousMicros= 0;

volatile unsigned long currentSpeed = 0;

volatile unsigned long previousSpeed = 0;

volatile unsigned long interval = 0;

unsigned long modInterval = 0;

float calFactor = .91; // decrease to slow down speedometer

// calFactor of 1 makes no change to speedometer

void setup()

{

pinMode (13, OUTPUT);

pinMode(speedometerPin, OUTPUT);

pinMode(sensorPin, INPUT);

digitalWrite (sensorPin, HIGH);

attachInterrupt (1, iSr, FALLING);

}
void loop()

{

noInterrupts();

modInterval=interval;

interrupts();

currentMicros = micros();

if (currentMicros-previousSpeed<1000000)

{

if (currentMicros - previousMicros>((modInterval/2)/calFactor))

{ previousMicros = currentMicros;

if (pulseState == LOW) pulseState = HIGH; else pulseState = LOW;

digitalWrite(13, pulseState); //to blink onboard LED

digitalWrite(speedometerPin, pulseState);

}

}

}

void iSr()

{

currentSpeed=micros();

if (digitalRead(sensorPin)==LOW)

{

if ((currentSpeed - previousSpeed) > debounce)

{

interval = currentSpeed - previousSpeed;

previousSpeed=currentSpeed;

}

}

}

2

Try by changing this line: if (currentMicros - previousMicros>((modInterval/2)/calFactor)) to the following:

if (currentMicros - previousMicros>((modInterval/2)/(analogRead(A0)/1000.0))  //0.000 - 1.023

Test Codes:

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  float calFactor = analogRead(A0)/1000.0;
  Serial.println(calFactor, 3); //connect A0-pin at 3.3V of UNO; Serial Monitor shows 0.667
  delay(1000);
}

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3

Thanks so much for the speedy answer did you think of any such code changes?

//1986 Porsche 944 Turbo Speedometer Calibrator

//Public Domain

//raw 944 transmission sensor signal must be processed by external schmitt trigger

//Schmitt trigger should bypass filer and pull-up resistor

//Use LM2940-10 with decoupling caps per datasheet to power Arduino in automotive setting

//Arduino Pin 7 supplies modified signal for speedometer

const int debounce = 2500;

const int speedometerPin = 7;

const int sensorPin = 3;

int pulseState = LOW;

volatile unsigned long currentMicros = 0;

volatile unsigned long previousMicros= 0;

volatile unsigned long currentSpeed = 0;

volatile unsigned long previousSpeed = 0;

volatile unsigned long interval = 0;

unsigned long modInterval = 0;

float calFactor = .91; // decrease to slow down speedometer

// calFactor of 1 makes no change to speedometer

if (currentMicros - previousMicros>((modInterval/2)/(analogRead(A0)/1000.0)) //0.000 - 1.023

void setup()
{
Serial.begin(9600);
}

void loop()
{
float calFactor = analogRead(A0)/1000.0;
Serial.println(calFactor, 3); //connect A0-pin at 3.3V of UNO; Serial Monitor shows 0.667
delay(1000);
}

void loop()

{

noInterrupts();

modInterval=interval;

interrupts();

currentMicros = micros();

if (currentMicros-previousSpeed<1000000)

{

{ previousMicros = currentMicros;

if (pulseState == LOW) pulseState = HIGH; else pulseState = LOW;

digitalWrite(13, pulseState); //to blink onboard LED

digitalWrite(speedometerPin, pulseState);

}

}

}

void iSr()

{

currentSpeed=micros();

if (digitalRead(sensorPin)==LOW)

{

if ((currentSpeed - previousSpeed) > debounce)

{

interval = currentSpeed - previousSpeed;

previousSpeed=currentSpeed;

}

}

}

4

Why have you not used the code tags (</>) to post your codes?

Why have you taken out this line: if (currentMicros - previousMicros>((modInterval/2)/(analogRead(A0)/1000.0)) //0.000 - 1.023 from the loop() function? It should be there where it was originally.

const int debounce = 2500;
const int speedometerPin = 7;
const int sensorPin = 3;
int pulseState = LOW;
volatile unsigned long currentMicros = 0;
volatile unsigned long previousMicros = 0;
volatile unsigned long currentSpeed = 0;
volatile unsigned long previousSpeed = 0;
volatile unsigned long interval = 0;
unsigned long modInterval = 0;
//float calFactor = .91;   // decrease to slow down speedometer
// calFactor of 1 makes no change to speedometer

void setup()
{
  pinMode (13, OUTPUT);
  pinMode(speedometerPin, OUTPUT);
  pinMode(sensorPin, INPUT);
  digitalWrite (sensorPin, HIGH);
  attachInterrupt (1, iSr, FALLING);
}

void loop()
{
  noInterrupts();
  modInterval = interval;
  interrupts();
  currentMicros = micros();
  if (currentMicros - previousSpeed < 1000000)
  {
    if (currentMicros - previousMicros > ((modInterval / 2) / (analogRead(A0) / 1000.0))) //calFactor))
    {
      previousMicros = currentMicros;
      if (pulseState == LOW)
        pulseState = HIGH;
      else
        pulseState = LOW;
      digitalWrite(13, pulseState);         //to blink onboard LED
      digitalWrite(speedometerPin, pulseState);
    }
  }
}

void iSr()
{
  currentSpeed = micros();
  if (digitalRead(sensorPin) == LOW)
  {
    if ((currentSpeed - previousSpeed) > debounce)
    {
      interval = currentSpeed - previousSpeed;
      previousSpeed = currentSpeed;
    }
  }
}
5

I tried the circuit and it changes the frequency from 1-99% to 250Hz for the frequency of frequency does not go up to max 30%?

6

pajper:
I tried the circuit and it changes the frequency from 1-99% to 250Hz for the frequency of frequency does not go up to max 30%?

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7

Thanks for the welcome this is when I think the signs are honored and I say does it or not for the full frequency range?

const int debounce = 2500;
const int speedometerPin = 7;
const int sensorPin = 3;
int pulseState = LOW;
volatile unsigned long currentMicros = 0;
volatile unsigned long previousMicros = 0;
volatile unsigned long currentSpeed = 0;
volatile unsigned long previousSpeed = 0;
volatile unsigned long interval = 0;
unsigned long modInterval = 0;
//float calFactor = .91; // decrease to slow down speedometer
// calFactor of 1 makes no change to speedometer

void setup()
{
pinMode (13, OUTPUT);
pinMode(speedometerPin, OUTPUT);
pinMode(sensorPin, INPUT);
digitalWrite (sensorPin, HIGH);
attachInterrupt (1, iSr, FALLING);
}

void loop()
{
noInterrupts();
modInterval = interval;
interrupts();
currentMicros = micros();
if (currentMicros - previousSpeed < 1000000)
{
if (currentMicros - previousMicros > ((modInterval / 2) / (analogRead(A0) / 1000.0))) //calFactor))
{
previousMicros = currentMicros;
if (pulseState == LOW)
pulseState = HIGH;
else
pulseState = LOW;
digitalWrite(13, pulseState); //to blink onboard LED
digitalWrite(speedometerPin, pulseState);
}
}
}

void iSr()
{
currentSpeed = micros();
if (digitalRead(sensorPin) == LOW)
{
if ((currentSpeed - previousSpeed) > debounce)
{
interval = currentSpeed - previousSpeed;
previousSpeed = currentSpeed;
}
}
}

8

If you expect to receive any answer, please carry out the following steps to post your codes using code tags (</>). You are violating the Forum Rules in spite of repeated requests for using code tags while posting codes.

And always use code tags (</>) when posting codes and the tips are:
1. Click on this icon </> of the toolbar of the posting window.
2. Copy your codes from the IDE.
3. Come back to this window and be sure you have the cursor blinking.
4. Just press Ctrl-V.