Arduino lookup table...best way to do this?

Projects Programming
7

So say i have 100 or more comparisons to do.....and each of the 100 values, needs to move the stepper/servos to some location, i would have to write 100 'if' statements?

that might be possible, but there are two generic solution:

  • arrays => use the index of the found value to set the value of a servo
  • formulas => you might be able to catch the logic in a (simple?) formula so you can calculate the position

array's example

#define MAXSERVOS 2

float arrayValues[] = { 2.25, 3.3, 4.75, 5.22, 6.12 };  // I added 1.0 to all the values of the original array

byte servoAngle[MAXSERVOS ][5] = {  // 5 angles per servo
 { 0, 45, 90, 135, 180 },
 { 0,10,20,30,40 } };  


...
  // find the value in the array
  for( x=0; x<4 && measuredValue <=arrayValues[x]; x++);

  // use the index to set the servo's
  for (int s=0; s< MAXSERVOS; s++)
  {
     servo[s].set(servoAngle[s][x]);  // note the servos are in an array too!
  }
...

that is in essence all (but you still have to type the whole array

formula example

   measurement = analogRead(0);
  //  set the servo's
  for (int s=0; s< MAXSERVOS; s++)
  {
     servo[s].set(func(s, measurement));   
  }

// the func(int s, float measurement) has to be elaborated, this is just an example.
float func(int s, float measurement) 
{
   float x = (measurement-512)/512.0; // map unto -1 .. 1
   float angle = (asin(x) + s * 30) % 180;
   return angle;
}

Mostly the array option is the easiest...