Digital Tachometer using IR Sensor

1#include <Arduino.h>
2#include <SPI.h>
3#include <Wire.h>
4unsigned  long rpmtime;
5float rpmfloat;
6unsigned int rpm;
7bool tooslow = 1;
8
9void  setup() {
10  Serial.begin(9600);
11  TCCR1A = 0;
12  TCCR1B = 0;
13  TCCR1B  |= (1 << CS12); //Prescaler 256
14  TIMSK1 |= (1 << TOIE1); //enable timer overflow
15  pinMode(2, INPUT);
16  attachInterrupt(0, RPM, FALLING);
17}
18
19ISR(TIMER1_OVF_vect)  {
20  tooslow = 1;
21}
22
23void loop() {
24  delay(1000);
25  if (tooslow  == 1) {
26    Serial.println("Too Slow");
27  }
28  else {
29    rpmfloat  = 120 / (rpmtime/ 31250.00);
30    rpm = round(rpmfloat);
31    Serial.println("RPM  = ");
32    Serial.println(rpm);
33  }
34}
35
36void RPM () {
37  rpmtime  = TCNT1;
38  TCNT1 = 0;
39  tooslow = 0;
40}
41

1#include <Arduino.h>
2#include <SPI.h>
3#include <Wire.h>
4unsigned
5  long rpmtime;
6float rpmfloat;
7unsigned int rpm;
8bool tooslow = 1;
9
10void
11  setup() {
12  Serial.begin(9600);
13  TCCR1A = 0;
14  TCCR1B = 0;
15  TCCR1B
16  |= (1 << CS12); //Prescaler 256
17  TIMSK1 |= (1 << TOIE1); //enable timer overflow
18
19  pinMode(2, INPUT);
20  attachInterrupt(0, RPM, FALLING);
21}
22
23ISR(TIMER1_OVF_vect)
24  {
25  tooslow = 1;
26}
27
28void loop() {
29  delay(1000);
30  if (tooslow
31  == 1) {
32    Serial.println("Too Slow");
33  }
34  else {
35    rpmfloat
36  = 120 / (rpmtime/ 31250.00);
37    rpm = round(rpmfloat);
38    Serial.println("RPM
39  = ");
40    Serial.println(rpm);
41  }
42}
43
44void RPM () {
45  rpmtime
46  = TCNT1;
47  TCNT1 = 0;
48  tooslow = 0;
49}
50