BUG Community

Welcome! Log In

Forums Recent Posts

Subscribe to Recent Posts 12,498 posts found

Apr 23, 2008 7:05pm
Medium kschultz 107 posts

Topic: BUGmodules / buglocate GPS info

Take a look at this:


Thanks Alex

Apr 23, 2008 4:24pm
drywall406 2 posts

Topic: BUGmodules / Accelerometer questions


I've been working to try to find the acceleration, velocity, and distance traveled from the accelerometer and I just have a few questions:

1. What is the default sensitivity of the accelerometer? I've read that this can be changed, but I haven't seen how to do so.

2. I've found the following equation that finds the acceleration due to gravity from the sensor reading. It requires knowledge of the sensor values at zero, +1g, and -1g acceleration and I was wondering if my values are accurate and/or if this is an appropriate function to use to determine acceleration.

z = 2(y - A) / (B - C)
A = sensor value at zero acceleration (I've found this to be around 500)
B = sensor value at +1g acceleration (around 660)
C = sensor value at -1g acceleration (around 330)
y = current sensor value
z = acceleration value

Multiplying z by 9.8 will convert z into meters per second squared.

3. I've somewhat been able to affect the behavior of the sample numbers, but I'm not quite sure what I'm supposed to be seeing. For example, if I move the accelerometer in the positive-y direction, how should the y-value be affected?

I have a general idea how the accelerometer works, but I'm looking for verification on how I'm using the data. Also, any documentation and/or suggestions regarding the accelerometer would be appreciated. Thanks.
Apr 23, 2008 12:24pm
aroman 21 posts

Topic: BUGmodules / buglocate GPS info

Hi Matt,

It’s a jupiter 32 chip and it is Sirf Star III. The product briefing is available here: www.navmanwireless.com/uploads/UT/hj/UThjwbdg2_…

By default the output of the gps module is set to NMEA 0813 and you can request an input stream to the raw data by using the INMEARawFeed OSGi service. To answer your question, the chip does support the Sirf Binary protocol.

There are ways to communicate directly with the GPS from Java, however, they are not exposed as OSGi Services. Could you open a feature request in bugzilla ( bugcommunity.com/bugzilla/ ) to add an OSGi service that supports Sirf Binary Protocol communications with the GPS?

A brief overview on how java access to our modules work:

Most of our hardware modules are represented by one or more linux character device drivers.

Each of these device drivers are accessible via a Java class called CharDevice. CharDevice mirrors the Linux character device driver interface: open(), read(), write(), close(), etc.

A CharDeviceInputStream can wrap a CharDevice to provide an InputStream to the device driver.

Based on this InpuStream we provide OSGi services tailored to the hardware module. For examples, the INMEASentenceProvider allows the client to get an RMC sentence object from the GPS input stream which in turn can be queried for latitude and longitude. However, if the client desires access to the raw data they can get an input stream to the output of the GPS via the OSGi service INMEARawFeed.

You are the first person that I know of requesting access to the Sirf Binary Protocol. However, as you can probably imagine, the architecture allows you to read and write bytes to the GPS module (CharDevice::read() CharDevice::write()) directly therefore supporting the Binary Protocol at this level from Java; It just needs to be carefully wrapped up into an OSGi service.

If you don’t mind, please open a feature request in our bugzilla.

I hope this information was useful to you and anyone that is interested.


Apr 23, 2008 6:33am
Medium agordon 74 posts

Topic: BUGmodules / buglocate GPS info

Angel monitors these forums. I believe he is also sometimes on the #buglabs IRC channel on freenode.

Apr 22, 2008 11:24pm
mattpease 2 posts

Topic: BUGmodules / buglocate GPS info

Hi Kevin -

Thanks for the information.

It sounds a little painful. How would I get in touch with Angel?

Thank you-

Apr 22, 2008 10:21pm
Medium kschultz 107 posts

Topic: BUGmodules / buglocate GPS info


More details are on the wiki here, including a link to the chipset manufacturers page with specs. It is a SiRF based chip. At the Java level there is not an inferface yet for what you are looking for, the inferface is only provides a position in a DD Lat/Lon position object. No meta-data or raw data is passed up to Java apps. That is something that would have to be added to the JNI driver, but it should be possible with some additional code. As for how complex a task that is, I believe Angel (aroman) is the one who did the GPS driver so he would know more about that.

Hope that helps some,
Apr 22, 2008 6:11pm
mattpease 2 posts

Topic: BUGmodules / buglocate GPS info

Hello Buglab -

What chip is inside the buglocate module? Is it a sirf star III?

Also, we need access to satellite pseudorange data. We want to build a logger that logs this data for later post-processing of GPS data.

To get at this data, we need to send the GPS SIRF binary commands.

And we’ll need to read the unfiltered sirf binary stream off the chip.

Does someone at Bug Labs know if the BugLocate module will do this?

Thank you-

Apr 22, 2008 3:09pm
akravets 25 posts

Topic: BUG SDK / Setting Virtual BUG home directory?

Hey Kevin,

If you open Virtual BUG Launch Configuration, there will be two tabs: Virtual BUG and Concierge. In Concierge tab, in properties table there is a property com.buglabs.osgi.cm.storage. The value for this property is where state of Virtual BUG is stored. The storage directory is OSGi’s storage directory.

The reason for two directories is because storage directory gets wiped out whenever framework is restarted (default behavior) and Virtual BUG’s storage directory is persisted between restarts.

Apr 22, 2008 2:49pm
Medium kschultz 107 posts

Topic: BUG SDK / Setting Virtual BUG home directory?

How do you change where the Virtual BUG leaves its files and looks for files?

I have Eclipse & Dragonfly installed at /dev/production/ but it goes straight to / when it looks for files and it also creates at least two directories (storage and in ~/ whenever the Virtual BUG runs. I think there is a way to change this and this question has been answered before but I couldn’t find the option.

Apr 21, 2008 6:04pm
User_img_not_found_05_med wimora 10 posts

Topic: BUGmodules / Module suggestions

I can see wanting to hook up to a TV.
What about an RCA and/or S-video out module?

Powered by Community Engine