Trying to do some math on some infrared readings and its killing me!

Projects Programming
1

Hi everyone!

So I'm making a robot using the FindBall Open IR sensor. It works great! But it can only give directions between 1 and 5, making it somewhat inaccurate, not to mention when the strengths of each sensor are so close to each other they jump wildly all over the place.

So.. I created (or tried to) a program that is supposed to using the strengths of two the strongest sensors, giving us a reading between 1 and 9. But the maths just aint working and its killing me!. My brain doesn't function anymore...

Heres the full code:

/*
Written by Julicrisby :smiley: 2017
Its not too good.
The sensor this refers too is the FindBall Open from Tris10.com

*/

#include <Array.h>
#include <I2C.h>
#include <Wire.h>
#include <math.h>
//#include <HMC5883.h>
#include <ADXL335.h> // ignore these libraries down here, they are for the parts of my robot present in the full program.
#include <HMC5883L.h>
#include <I2Cdev.h>
#include <HMC5883L.h>

#define FB_ADDR_7BIT (0x02 >> 1) // Here 0x02 gets bit-shifted to 0x01, I dont know why. FindBall 7-Bit Address is 0x01

unsigned char read_byte(unsigned char addr, unsigned char reg) { //Findball Open's IIC commandline
Wire.beginTransmission(addr); //The FindBall Open board has 5 individual IR sensors on it.
Wire.write(reg);//ranges from 0x42 -> 0x48. 0x42 returns the best sensor (1, 2, 3,4 or 5), 0x43 returns that sensors strength
Wire.endTransmission(); // 0x44 -> 0x48 return the strengths of the individual sensors. 0x44 being sensor 1 on the left, 0x48 being sensor 5 on the right

Wire.requestFrom((uint8_t) addr, (uint8_t) 1);
if (Wire.available()) {
return Wire.read(); // succeeeed
} else {
return 255; // error
}
}

void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
Wire.begin(); //so we can talk on the IIC bus
}

void loop() {
// put your main code here, to run repeatedly:
int dir, maxa, max2, wantedpos, wantedpos2;
int sen1 = read_byte(FB_ADDR_7BIT, 0x44);
Serial.println("Sensor 1: ");
Serial.println(sen1);
int sen2 = read_byte(FB_ADDR_7BIT, 0x45);
Serial.println("Sensor 2: ");
Serial.println(sen2);
int sen3 = read_byte(FB_ADDR_7BIT, 0x46);
Serial.println("Sensor 3: ");
Serial.println(sen3);
int sen4 = read_byte(FB_ADDR_7BIT, 0x47);
Serial.println("Sensor 4: ");
Serial.println(sen4);
int sen5 = read_byte(FB_ADDR_7BIT, 0x48);
Serial.println("Sensor 5: ");
Serial.println(sen5);
const byte size = 5;
int senArray = {sen1, sen2, sen3, sen4, sen5};
Array array = Array(senArray,size);
maxa = array.getMax();
Serial.println("Max value of first array (senArray): ");
Serial.println(maxa);
for (int i=0; i<5; i++) {
if(maxa!=senArray*) continue;*

  • else wantedpos = i + 1, Serial.println("The position of that number in the array: "), Serial.println(wantedpos);*
  • }*
  • const byte size2 = 4;*
  • int senArray2[size2];*
  • int j = 0;*
  • for (int i=0; i<size2; i++) {*
    _ if(i != wantedpos - 1) senArray2[j] = senArray*, j++;_
    _     else continue;_
    _     }_
    _     Array array2= Array(senArray2,size2);_
    _     max2 = array2.getMax();_
    _     Serial.println("Max value of second array (senArray2): ");_
    _     Serial.println(max2);_
    _     for (int i=0; i<4; i++) {_
    _ if(max2!=senArray2) continue;
     else wantedpos2 = i + 1,Serial.println("The position of that number in the array: "), Serial.println(wantedpos2);
     }
     if (wantedpos = wantedpos2 = 0) {
     //return 0;
     Serial.println("It is zero and i am annoyed.");
     }
     else if (maxa - max2 < 75) { //75 is arbitrary number, in reality its probably closer to 10*
    * dir = 0;
     dir = (wantedpos + wantedpos2) - 1; //the final heading. -1 because 1 + 1 still has to equal 1 and 5 + 5 cant equal 10*
    * Serial.println("maxa-max2 is less than 75: ");
     Serial.println(dir); //Except, dir returns -1! Even though wantedpos and wantedpos2 both equal positive numbers that arent 0.
     } else {
     dir = 0;
     dir = (wantedpos + wantedpos) - 1;
     Serial.println("maxa-max2 is not less that 75: ");
     Serial.println(dir);
     }
     Serial.println("help me");
     delay(5000);
    }[/quote]
    So my big issue is that down the bottom, where it starts adding wantedpos and wantedpos2 together, no matter what they each equal, -1 is returned. Does anyone have any suggestions?
    (referring to this bit)
    > else if (maxa - max2 < 75) { //75 is arbitrary number, in reality its probably closer to 10*
    > dir = 0;
    > dir = (wantedpos + wantedpos2) - 1; //the final heading. -1 because 1 + 1 still has to equal 1 and 5 + 5 cant equal 10
    > Serial.println("maxa-max2 is less than 75: ");
    > Serial.println(dir); //Except, dir returns -1! Even though wantedpos and wantedpos2 both equal positive numbers that arent 0.
    > }
    god help me :smiley:_
2 
    else wantedpos = i + 1, Serial.println("The position of that number in the array: "), Serial.println(wantedpos);

When you want a series of commands executed they need to be separated by semicolons, not commas. Better still they should be on separate lines as well and they must be enclosed in curly brackets

 else 
 {  
   wantedpos = i + 1;
   Serial.println("The position of that number in the array: ");
   Serial.println(wantedpos);
 }
3

While what you said is true in some spots, the code still works with the commands separted by commas. Sadly the issue is unrelated to this abnormal syntax, and is more likely due to the fact that the 'wantedpos' variables are being defined within a 'for' loop, but I do not know how to get around this.

4

Oh gee, Dont worry guys I fixed it!

So yeah... I had done " if (wantedpos = wantedpos2 = 0) " thinking that in the context of an IF statement, the compiler would just look at the values, but no... It was actually setting their value to 0. What i needed was to use '==' instead of '='

Edit: So instead the code would be:

if (wantedpos == 0 && wantedpos2 == 0) {

}