Ciao ragazzi, stavo vedendo lo sketch di esempio per l'accelerometro adxl377, che sta sul sito della adafruit.
Questo e' il link: ADL377.
Non mi e' chiara una cosa, perche' quando usa il comando map, mette come nuovi valori -1000 e 1000?
Questo accelerometro lavora tra -200g e 200g, non dovrebbero essere questi i due estremi?
const int xInput = A0;
const int yInput = A1;
const int zInput = A2;
const int buttonPin = 2;
// Raw Ranges:
// initialize to mid-range and allow calibration to
// find the minimum and maximum for each axis
int xRawMin = 512;
int xRawMax = 512;
int yRawMin = 512;
int yRawMax = 512;
int zRawMin = 512;
int zRawMax = 512;
// Take multiple samples to reduce noise
const int sampleSize = 10;
void setup()
{
analogReference(EXTERNAL);
Serial.begin(9600);
}
void loop()
{
int xRaw = ReadAxis(xInput);
int yRaw = ReadAxis(yInput);
int zRaw = ReadAxis(zInput);
if (digitalRead(buttonPin) == LOW)
{
AutoCalibrate(xRaw, yRaw, zRaw);
}
else
{
Serial.print("Raw Ranges: X: ");
Serial.print(xRawMin);
Serial.print("-");
Serial.print(xRawMax);
Serial.print(", Y: ");
Serial.print(yRawMin);
Serial.print("-");
Serial.print(yRawMax);
Serial.print(", Z: ");
Serial.print(zRawMin);
Serial.print("-");
Serial.print(zRawMax);
Serial.println();
Serial.print(xRaw);
Serial.print(", ");
Serial.print(yRaw);
Serial.print(", ");
Serial.print(zRaw);
// Convert raw values to 'milli-Gs"
long xScaled = map(xRaw, xRawMin, xRawMax, -1000, 1000);
long yScaled = map(yRaw, yRawMin, yRawMax, -1000, 1000);
long zScaled = map(zRaw, zRawMin, zRawMax, -1000, 1000);
// re-scale to fractional Gs
float xAccel = xScaled / 1000.0;
float yAccel = yScaled / 1000.0;
float zAccel = zScaled / 1000.0;
Serial.print(" :: ");
Serial.print(xAccel);
Serial.print("G, ");
Serial.print(yAccel);
Serial.print("G, ");
Serial.print(zAccel);
Serial.println("G");
delay(500);
}
}
//
// Read "sampleSize" samples and report the average
//
int ReadAxis(int axisPin)
{
long reading = 0;
analogRead(axisPin);
delay(1);
for (int i = 0; i < sampleSize; i++)
{
reading += analogRead(axisPin);
}
return reading / sampleSize;
}
//
// Find the extreme raw readings from each axis
//
void AutoCalibrate(int xRaw, int yRaw, int zRaw)
{
Serial.println("Calibrate");
if (xRaw < xRawMin)
{
xRawMin = xRaw;
}
if (xRaw > xRawMax)
{
xRawMax = xRaw;
}
if (yRaw < yRawMin)
{
yRawMin = yRaw;
}
if (yRaw > yRawMax)
{
yRawMax = yRaw;
}
if (zRaw < zRawMin)
{
zRawMin = zRaw;
}
if (zRaw > zRawMax)
{
zRawMax = zRaw;
}
}
Grazie,
Antonio