accelerometer-simple.c

基于phidget标准C程序样例

// - Accelerometer simple -
// This simple example simply creates an accelerometer handle, creates it, hooks the event handlers and opens it.  It then waits
// for an accelerometer to be attached and waits for events to be fired. We preset the sensitivity of each axis to 0.5 to make it
// easier to see the event data.  For a more detailed example with the ability to see and manipulate all of the accelerometer
// Phidget's properties, see the Accelerometer-full example.
//
// Please note that this example was designed to work with only one Phidget Accelerometer connected. For an example using multiple 
// Phidget Accelerometers, please see a "multiple" example in the Accelerometer Examples folder.
//
// Copyright 2007 Phidgets Inc.  All rights reserved.

#include <stdio.h>
#include <phidget21.h>

double past_samples[3];

//callback that will run if the Accelerometer is attached to the computer
int AttachHandler(CPhidgetHandle IFK, void *userptr)
{
	int serialNo;
	CPhidget_getSerialNumber(IFK, &serialNo);
	printf("Accelerometer %10d attached!", serialNo);

	return 0;
}

//callback that will run if the Accelerometer is detached from the computer
int DetachHandler(CPhidgetHandle IFK, void *userptr)
{
	int serialNo;
	CPhidget_getSerialNumber(IFK, &serialNo);
	printf("Accelerometer %10d detached!", serialNo);

	return 0;
}

//callback that will run if the Accelerometer generates an error
int ErrorHandler(CPhidgetHandle IFK, void *userptr, int ErrorCode, const char *unknown)
{
	printf("Error handled. %i - %s", ErrorCode, unknown);
	return 0;
}

//callback that will run if the acceleration changes by more than the Acceleration trigger.
//Index - Index of the axis that is generating the event, Value - the value read by the accelerometer axis
int accel_AccelChangeHandler(CPhidgetAccelerometerHandle WGT, void *userptr, int Index, double Value)
{
	

	past_samples[Index] = (past_samples[Index] * 0.90) + (Value * 0.10);
	
	printf("Axis: %i -- %6f\n", Index, past_samples[Index]);

	

	return 0;
}

//Display the properties of the attached phidget to the screen.  We will be displaying the name, serial number, version of the attached device and number of Axes on the accelerometer.
int display_properties(CPhidgetHandle phid)
{
	int serialNo, version;
	const char* ptr;
	int numAxes;

	CPhidget_getDeviceType(phid, &ptr);
	CPhidget_getSerialNumber(phid, &serialNo);
	CPhidget_getDeviceVersion(phid, &version);
	CPhidgetAccelerometer_getNumAxis((CPhidgetAccelerometerHandle)phid, &numAxes);

	printf("%s\n", ptr);
	printf("Serial Number: %10d\nVersion: %8d\n", serialNo, version);
	printf("Number of Axes: %i\n", numAxes);

	return 0;
}

int accelerometer_simple()
{
	int result, numAxes;
	const char *err;

	//Declare an accelerometer handle
	CPhidgetAccelerometerHandle accel = 0;

	//create the accelerometer object
	CPhidgetAccelerometer_create(&accel);

	//Set the handlers to be run when the device is plugged in or opened from software, unplugged or closed from software, or generates an error.
	CPhidget_set_OnAttach_Handler((CPhidgetHandle)accel, AttachHandler, NULL);
	CPhidget_set_OnDetach_Handler((CPhidgetHandle)accel, DetachHandler, NULL);
	CPhidget_set_OnError_Handler((CPhidgetHandle)accel, ErrorHandler, NULL);

	//Registers a callback that will run if the acceleration changes by more than the Acceleration trigger.
	//Requires the handle for the Accelerometer, the function that will be called, and an arbitrary pointer that will be supplied to the callback function (may be NULL)
	CPhidgetAccelerometer_set_OnAccelerationChange_Handler(accel, accel_AccelChangeHandler, NULL);

	//open the acclerometer for device connections
	CPhidget_open((CPhidgetHandle)accel, -1);

	//get the program to wait for an accelerometer device to be attached
	printf("Waiting for accelerometer to be attached....");
	if((result = CPhidget_waitForAttachment((CPhidgetHandle)accel, 10000)))
	{
		CPhidget_getErrorDescription(result, &err);
		printf("Problem waiting for attachment: %s\n", err);
		return 0;
	}

	//Display the properties of the attached accelerometer device
	display_properties((CPhidgetHandle)accel);

	//read accelerometer event data
	printf("Reading.....\n");

	//get the number of available axes on the attached accelerometer
	CPhidgetAccelerometer_getNumAxis(accel, &numAxes);

	//Most accelerometers have 2 axes so we'll pre-set their sensitivity to make the data more readable
	CPhidgetAccelerometer_setAccelerationChangeTrigger(accel, 0, 0.500);
	CPhidgetAccelerometer_setAccelerationChangeTrigger(accel, 1, 0.500);

	//If the accelerometer attachedi s a 30axis, we'll set the sensitivity of the 3rd axis
	if(numAxes > 2)
	{
		CPhidgetAccelerometer_setAccelerationChangeTrigger(accel, 2, 0.500);
	}

	//wait until user input is read
	printf("Press any key to end\n");
	getchar();

	//since user input has been read, this is a signal to terminate the program so we will close the phidget and delete the object we created
	printf("Closing...\n");
	CPhidget_close((CPhidgetHandle)accel);
	CPhidget_delete((CPhidgetHandle)accel);

	//all done, exit
	return 0;
}

//main entry point to the program
int main(int argc, char* argv[])
{
	accelerometer_simple();
	return 0;
}