Accelerometer

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

<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.

Read Accelerometer from hidd

1. Implement the sample code in hidd
2. 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>

Sample code

Taken from boydell's Magic 8 Ball app:

In his first-assistant.js (... = code skips) <source lang="javascript"> ...

       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>

To increase the resolution to 30Hz, use this snippet (requires WebOS 1.3.5 or above): <source lang="javascript"> this.controller.stageController.setWindowProperties("fastAccelerometer"); </source>