Posts Tagged ‘gps’

GPS Intermediate Driver for Windows Mobile (and getting it to work!)

Monday, August 25th, 2008

My last two Windows Mobile phones have both had GPS, so I’ve played with code to get my location from the GPS a few times. These have generally been quick hacked-together bits and pieces. In all of them, I wrote my own GPS code. I knew that the GPS device would be accessible through a serial port, so I just connected to the relevant COM port and started reading. It’s easy to parse – NMEA sentences are written with an update on each line, in comma-separated strings.

After sharing my OpenCellId client last week, I was encouraged to try rewriting the GPS code for it using the Windows Mobile GPS Intermediate Driver. So I had a quick try. I was vaguely aware of it before, but hadn’t taken a proper look. In this post, I’ll describe briefly what it is, it’s benefits over home-grown hacks such as my own, and share a couple of things that I had to do to get it to work.

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OpenCellId for Windows Mobile

Tuesday, August 19th, 2008

I talked about this yesterday, but it’s ready for sharing now.

screenshotWhat is this?
It’s a OpenCellID client for Windows Mobile

What does that mean?
It uses the GPS device connected to a Windows Mobile device (either internal or connected over Bluetooth) to identify exact latitude / longitude coordinates.

It combines this with the cell id of the GSM tower that your phone is currently communicating with.

These two measurements are uploaded to the database at OpenCellId.org

Why?
Because if enough people do this, then we will be able to build up a picture of where each GSM cell is.

Then people without GPS (either because their mobile devices don’t have GPS, or because their indoors) can work out where they are by looking up their current GSM cell in the OpenCellId database.

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OpenCellId – collecting data for mobile location-based services

Monday, August 18th, 2008

It is great to see a revived buzz around mobile location based apps and services. There are lots of new services to try. I try loads of them, the most recent was Moot just a few days ago (I love their video which I’ve embedded here – very cute), but there are way more than I can keep up with.

One problem they all share before they get to offer you their variations on useful location-based services is how to figure out where you are in the first place.

GPS is an obvious response, but not everyone has it on their mobile, and even if you do, it has some big problems – it can take a while to get a fix, won’t work indoors, etc.

Good solutions supplement this with other sources of information. Skyhook is getting a lot of attention at the moment for their service – mainly due to it being used in the iPhone. It means that the iPhone (and other devices using Skyhook) can work out where it is using GPS, but if a GPS fix cannot be made (or in the interim time while waiting for one) it can give an approximate location almost instantly using cell-tower triangulation and/or known WiFi access points.

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Programmatically getting the CellID from your Windows Mobile phone

Wednesday, March 12th, 2008

I’m still on paternity leave at the moment, so time near a computer is limited to 20 or 30 minute periods in the rare occasions while Faith is asleep!

But in the last few days, I’ve still been playing with a few new geeky things. One of these is FindMe – a Windows Mobile application from Electric Pocket.

screenshot of FindMeThe basic idea is:

  • it gets the CellID of the GSM transmitter that your mobile phone is currently talking to
  • if it hasn’t seen this CellID before, it displays “You are in a new place” and prompts you to type in a name for where you are
  • if it has seen this CellID before, it uses the name you last entered for it

Then it uploads your name for the CellID (your description for where you are) to your Facebook profile.

Hey presto – location tracking without the need for GPS.

It works quite well.

I’ve played with location based stuff on my phone before but never tried to use GSM cell id before. I did consider it, but after failing to find a free database that could transform the cell id string into a location I could plot on a map, I didn’t really pursue it any further.

Playing with FindMe encouraged me to give it a try.

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Posted in code | 115 Comments »