I built a small centrifuge and I’m trying to count the RPMs using an E18-D80NK IR sensor. It’s connected to pin 2 of an Arduino Micro which is interrupt 1. I got the RPM code from the arduino.cc site (http://playground.arduino.cc/Main/ReadingRPM). It should count the interrupts and then calculate the RPM.
My issue is that after about 30 seconds or so, my RPM value goes to 0 and stays there and I have no idea why. It should keep showing the RPM value indefinitely.
If I don’t spin it, and let the RPM remain at 0, then try to run it after 30 seconds or so, it stays at 0
Once it goes to 0, it will always stay at 0 until I do a reset of the arduino micro.
Also, if I stop spinning it before it does the perma-0 thing, it stays at the last value instead of going to 0 like it should.
How can I fix this please?
//code for the OLED display
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define OLED_DC 11
#define OLED_CS 12
#define OLED_CLK 10
#define OLED_MOSI 9
#define OLED_RESET 13
Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);
#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2
#define LOGO16_GLCD_HEIGHT 16
#define LOGO16_GLCD_WIDTH 16
static unsigned char PROGMEM logo16_glcd_bmp[] =
{ B00000000, B11000000,
B00000001, B11000000,
B00000001, B11000000,
B00000011, B11100000,
B11110011, B11100000,
B11111110, B11111000,
B01111110, B11111111,
B00110011, B10011111,
B00011111, B11111100,
B00001101, B01110000,
B00011011, B10100000,
B00111111, B11100000,
B00111111, B11110000,
B01111100, B11110000,
B01110000, B01110000,
B00000000, B00110000 };
//variables for rpm counting
int rpmcount = 0;
int timeold =0;
int rpm;
unsigned int potPin = 8; // select the input pin for the potentiometer
int val = 0; // variable to store the value coming from the sensor
unsigned int btnpin = 3; // pin for the set button
int setval = 0; // set value variable
int spd= 0; // spd var for motor control function
unsigned int button_push = 5; // Set button value high
unsigned int delta = 0; // var for difference between actual and desired rpm
// OLED code
#if (SSD1306_LCDHEIGHT != 64)
#error("Height incorrect, please fix Adafruit_SSD1306.h!");
#endif
//diabled speed control until rpm error is figured out
/*
int motor_cont(int spd)
{
int delta2 = spd - rpm;
delta = abs(delta2);
if (rpm < spd){
val = val ++;
}
if (rpm > spd){
val = val --;
}
if (setval < 10){
val = 0;
}
if (val < 0){
val = 0;
}
delay(100);
return val;
}
*/
// function for rpm calculation
void rpm_fun()
{
rpmcount++;
//Each rotation, this interrupt function is run twice
}
void setup() {
attachInterrupt(1, rpm_fun, FALLING); // IR signal wire connected to pin 2 which is interrupt 1, int caused on going from +5 to 0v
rpmcount = 0; // initializing rpm variables
rpm = 0;
timeold = 0;
//button stuff disabled until rpm problem resolved
//pinMode(btnpin, INPUT); //Set pin 3 as input for the button
//digitalWrite(btnpin, HIGH); //Enable pull up resistor for button input
digitalWrite(2, HIGH); //Enable pull up resistors for IR sensor input
//output for L298N motor control
pinMode(5, OUTPUT);
pinMode(4, OUTPUT);
pinMode(6, OUTPUT);
// OLED code
// by default, we'll generate the high voltage from the 3.3v line internally! (neat!)
display.begin(SSD1306_SWITCHCAPVCC);
// init done
display.display(); // show splashscreen
delay(1000);
display.clearDisplay(); // clears the screen and buffer
}
void loop() {
// RPM calculator
if (rpmcount >= 20) {
//Update RPM every 20 counts, increase this for better RPM resolution,
//decrease for faster update
rpm = 30*1000/(millis() - timeold)*rpmcount;
timeold = millis();
rpmcount = 0;
}
// g force calculation disabled until rpm issue resolved
//unsigned int Gs = 1.12 * 125 * rpm/1000 * rpm/1000;
// code to display data to OLED
display.setTextSize(1);
display.setTextColor(WHITE);
display.setCursor(0,0);
display.println("Centrifuge 2.0 by");
display.println("David Dominguez");
display.println();
display.print("Desired RPM: ");
display.setTextSize(1);
display.println(setval);
display.setTextSize(1);
display.print("Set RPM: ");
display.setTextSize(1);
display.println(spd);
display.setTextSize(1);
display.print("PWM Value: ");
display.println(val);
display.print("Actual RPM: ");
display.println(rpm);
display.print("G-Force: ");
//display.print(Gs);
display.display();
display.clearDisplay(); // clears the screen and buffer
setval = analogRead(potPin); // read the value from the sensor
/*button_push = digitalRead(btnpin);
if (button_push < 1){
spd = setval;
}
val = motor_cont(spd);
*/
//Motor control
analogWrite(6, setval/4);
digitalWrite(5, LOW);
digitalWrite(4, HIGH);
}
