Accelerometer - Revision history

Zinge: added note about lightweight stages

2010-04-04T00:37:25Z

added note about lightweight stages

Schulman at 06:25, 3 February 2010

2010-02-03T06:25:52Z

Bsiegel at 22:58, 20 January 2010

2010-01-20T22:58:30Z

Sushi at 06:20, 25 July 2009

2009-07-25T06:20:29Z

Sugardave: added to category Hardware

2009-07-19T01:08:16Z

added to category Hardware

Sugardave: Initial creation

2009-07-19T00:28:50Z

Initial creation

New page

The accelerometer appears to be a "KXSD9 SERIES Tri-Axis, 2g, 4g, 6g, 8g, User Selectable, Ultra Low Power Digital"
[http://www.kionix.com/accelerometers/accelerometer-KXSD9.html http://www.kionix.com/accelerometers/accelerometer-KXSD9.html]

<source lang="text">
root@castle:/sys/class/input/input5# cat name
kxsd9_accelerometer
</source>

more info:
<source lang="text">
root@castle:/sys/class/input/input5# cat uevent
PHYSDEVPATH=/class/i2c-adapter/i2c-3/3-0018
PHYSDEVBUS=i2c
PHYSDEVDRIVER=kxsd9_accelerometer
PRODUCT=18/1/1/100
NAME="kxsd9_accelerometer"
EV==9
ABS==7
MODALIAS=input:b0018v0001p0001e0100-e0,3,kra0,1,2,mlsfw
</source>

and at the very least you could adjust the low pass filter used, or the threshold for waking up:

<source lang="text">
root@castle:/sys/class/input/input5# ls -al
drwxr-xr-x 6 root root 0 Jun 11 17:47 .
drwxr-xr-x 8 root root 0 Jun 11 17:47 ..
-rw-r--r-- 1 root root 4096 Jun 11 23:58 accelerometer_filter_frequency
-rw-r--r-- 1 root root 4096 Jun 11 23:58 accelerometer_motion_wake_up_threshold
drwxr-xr-x 2 root root 0 Jun 11 23:58 capabilities
lrwxrwxrwx 1 root root 0 Jun 11 23:58 device -> ../../../class/i2c-adapter/i2c-3/3-0018
drwxr-xr-x 3 root root 0 Jun 11 23:49 event5
drwxr-xr-x 2 root root 0 Jun 11 23:58 id
lrwxrwxrwx 1 root root 0 Jun 11 23:58 input:event5 -> ../../../class/input/input5/event5
-r--r--r-- 1 root root 4096 Jun 11 23:58 modalias
-rw-r--r-- 1 root root 0 Jun 11 23:50 mode
-r--r--r-- 1 root root 4096 Jun 11 23:53 name
-r--r--r-- 1 root root 4096 Jun 11 23:58 phys
-rw-r--r-- 1 root root 4096 Jun 11 23:58 poll_interval
drwxr-xr-x 2 root root 0 Jun 11 23:58 power
lrwxrwxrwx 1 root root 0 Jun 11 23:58 subsystem -> ../../../class/input
-rw-r--r-- 1 root root 4096 Jun 11 23:58 uevent
-r--r--r-- 1 root root 4096 Jun 11 23:58 uniq
</source>

More accelerometer info

There's a library called libhidaccelerometer.so -- so it's treated as an HID class of devices. There is no dbus activity when you move the device, so this probably a much lower level service. Makes sense: you don't want zillions of dbus messages firing off whenever someone moves.

Looking in running processes, I notice /usr/bin/hidd, which references a configuration file '''/etc/hidd/HidPlugins.xml'''

In this file, two sockets are mentioned:
/var/tmp/hidd/AccelerometerCmdSocket
/var/tmp/hidd/AccelerometerEventSocket

These are UNIX DGRAM sockets, which are open on the device.

@@ Line 131: / Line 131: @@
 this.controller.stageController.setWindowProperties("fastAccelerometer");
 </source>
 [[Category:Hardware]]

← Older revision		Revision as of 06:25, 3 February 2010
Line 57:		Line 57:

	These are UNIX DGRAM sockets, which are open on the device.		These are UNIX DGRAM sockets, which are open on the device.
		+
		+	== Read Accelerometer from hidd ==
		+
		+	# Implement the sample code in [[hidd]]
		+	# Change the main function to below
		+
		+	<source lang="c">
		+	char code_names[] = {'x','y','z'};
		+
		+	int main() {
		+	void *pHandle;
		+	struct input_event myevents[20];
		+	int ret = 0;
		+	int i = 0;
		+
		+	pHandle = HidEventOpen(1);
		+
		+	while (1) {
		+	ret = HidEventRead(pHandle, myevents, 20);
		+
		+	for (i = 0; i < ret; i++)
		+	{
		+	float* value = (float*)(&myevents[i].value);
		+	if (myevents[i].type == 3 &&
		+	myevents[i].code < 3)
		+	{
		+	printf("%c: %f ",
		+	code_names[myevents[i].code],
		+	*value);
		+	}
		+	}
		+	printf("\n");
		+	}
		+	HidEventDeInit();
		+	HidEventClose(pHandle);
		+	return 0;
		+	}
		+
		+	</source>

@@ Line 63: / Line 63: @@
 In his '''first-assistant.js''' (''... = code skips'')
-<source lang="text">
+<source lang="javascript">
 ...
          this.controller.listen(this.controller.sceneElement, Mojo.Event.tap, this.handleTap.bind(this));
@@ Line 85: / Line 85: @@
          this.showRandomMessage();
          Event.stop(event);
 </source>
 [[Category:Hardware]]

← Older revision		Revision as of 06:20, 25 July 2009
Line 57:		Line 57:

	These are UNIX DGRAM sockets, which are open on the device.		These are UNIX DGRAM sockets, which are open on the device.
		+
		+
		+	== Sample code ==
		+	Taken from boydell's Magic 8 Ball app:
		+
		+	In his '''first-assistant.js''' (''... = code skips'')
		+	<source lang="text">
		+	...
		+	this.controller.listen(this.controller.sceneElement, Mojo.Event.tap, this.handleTap.bind(this));
		+	this.controller.listen(document, 'shakestart', this.handleShakeStart.bind(this));
		+	this.controller.listen(document, 'shaking', this.handleShaking.bind(this));
		+	this.controller.listen(document, 'shakeend', this.handleShakeEnd.bind(this));
		+	...
		+	FirstAssistant.prototype.handleShakeStart = function(event) {
		+	this.setBall();
		+	this.hideMessage();
		+	Event.stop(event);
		+	}
		+
		+	FirstAssistant.prototype.handleShaking = function(event) {
		+	this.setBall();
		+	this.hideMessage();
		+	Event.stop(event);
		+	}
		+
		+	FirstAssistant.prototype.handleShakeEnd = function(event) {
		+	this.showRandomMessage();
		+	Event.stop(event);
		+	</source>
		+
		+
	[[Category:Hardware]]		[[Category:Hardware]]

← Older revision		Revision as of 01:08, 19 July 2009
Line 57:		Line 57:

	These are UNIX DGRAM sockets, which are open on the device.		These are UNIX DGRAM sockets, which are open on the device.
		+	[[Category:Hardware]]