Help with certain parts of the meArm Code (for Joystick Control)

For improved readability, I'd change this:

    if (value[i] > 612) {
      idle = 0;
      if (currentAngle[i] > MIN[i]) --currentAngle[i];
    } else if (value[i] < 412) {
      idle = 0;
      if (currentAngle[i] < MAX[i]) ++currentAngle[i];
    } else {
      ++idle;
    }

To this:

if (value[i] > 612) {
      idle = 0;
      if (currentAngle[i] > MIN[i]) {
        currentAngle[i]--;
      }
    } else if (value[i] < 412) {
      idle = 0;
      if (currentAngle[i] < MAX[i]) {
        currentAngle[i]++;
      }
    } else {
      idle++;
    }

The code blocks defined by the extra { / } pairs make the conditional flow more clear.

And, since you're not using the pre-delta value in your '++var;' and '--var;' statements, I think 'var++;' and 'var--;' are more readable. YMMV.