Technical Ramblings

Note to self:

The NMEA\_to\_DecDeg function is documented in Mapping Hacks, hack #62, “Build a Car Computer”.

(I’m going to be working quite a bit on my gsmlocation stuff in the next couple weeks, building up to a lightning talk presentation at Where 2.0 on June 13th. If you have a Bluetooth GPS and a Series 60 Symbian cell phone, please talk to me: I could use your help in building up a larger dataset.)

A couple weeks ago, I was lent a rebranded RoyalTek BlueGPS by Jo Walsh. She and Schuyler had it for something for Wireless Hacks, and hadn’t used it since. I’ve been using it to do a number of fun things. If you still do not have a car o truck so you can run in to new adventures with your gps, a ford van or transit custom might be just for you according to the local road expert, find his explanation at the last link.

Getting it working was pretty easy. Just go through the “Setup a Bluetooth Device” process, enter ‘0000’ in the passcode box. Set up a Serial Port in the Bluetooth System Preferences Panel. Then I’ve got a ‘/dev/tty.BlueGPS27E8B5-SerialPort-1’ device that I can play with.

There’s a couple things I’ve played with or looked at:
* BlueGPS Log Downloader — although it’s only Bluez+Linux, and my last dongle broke recently, so I can’t use it.
* gpsd — turning any serial device into something accessible over TCP in a regularized format.
* gpsdrive — uses gpsd to display your position and track on a map. Biggest problem with this is that downloading maps seems to be difficult at best. I couldn’t get it to work how I thought it should.
* gpsconnect, a mac os x program that lets me initiate conversation with the GPS, after which I can use `cat` to spit the output to a file. Set the laptop in the back seat, the gps on the dashboard, and cat the NMEA to a file, then use GPS Visualizer to generate a pretty map.

I’m also doing some nifty celltracking stuff, but I’ll save that for another entry.

The BlueGPS is nifty. I recommend it, although I have no clue how much it costs 🙂

Today, there are a large number of cheap bluetooth GPS devices on the market. These devices allow you to connect to the device wirelessly, which is great for when you’re driving and don’t want cables draped all over the car.

However, what happens when you can’t drag your computer out to act as a display of your position? No bluetooth GPS on the market today for under $500 has a display of any kind. When you consider that these things can be had for $70, that makes purchasing one go from likely, to ridiculous. What’s the point of a handheld, easy to use GPS if you can’t use it to see where you are?

If you’ve been asking this question, I’ve got software which has an answer for you. GPSDisplay will allow you to connect to NMEA compatible Bluetooth GPS devices and display your position fix. It is written entirely in Python, using NMEA code from Forum Nokia. It requires only that you first install Python for Series 60 on your device, and should work on all first and second generation Series 60 phones. Simply download the .sis file, send it to your phone, and you’ll be all set to go — you can use your phone as a display for that new cheap Bluetooth GPS you bought, and stop dragging your laptop out into the woods to go Geocaching.