When I last left the data logger project off I was having quite a few issues with managing the size of the data in the allotted EEPROM space on board the Arduino. I built up an SDCard writer based on several specs I found in the messageboard and it worked flawlessly. I successfully captured RPM data from my bicycle commute. The problem was, I had no way to correlate one collection of data to the other. Different routes, days, time, weather could all affect the results of the dataset.
It was never on my list of things to do since I knew the battery usage scenario would be so high, but I figured I’d bite the bullet and go the GPS route anyways. I picked up LadyAda’s GPS Sheild and have had a wonderful time working with it ever since.
I had been working on a way to parse the NMEA string data from the GPS device delivers when I figured it would be a perfect way to try out the Google Maps Flash API (my previous experience had only been using the JavaScript API, and Yahoo Maps API) and Flash Player 10. Flash Player 10 offers a number of new features, one of which being the FileReference API which allows you to browse for a file on your local machine and load it into the Flash Player without making a round trip to the server. Once loaded I split the text file based on the carriage return and cast all of the GPS Points to a Vector (another new feature — typecast Array. The speed difference is quite staggering!).
The end result is plotted on a map and colour coded based on velocity, which is recorded in Knots and translated to Km/h. The end result is a colourful chart of the route I commuted that particular day.
In the screenshot above, note the big red blotch at Allen Gardens — flat tire. The other red marks are stop lights or streetcars.
An example of the map in action requires some coordinates, so save these text files to your machine first (contains a couple hundred lines of NMEA data), and hit the load button in the map application. Once loaded the map should recentre on the coordinate boundary.
I’m currently working on some new modifications for the map so I should have more available soon. But first I’m putting the finishing touches on a wooden case I’m hand crafting as a shell for the GPS device. I’ll have photos up from that project soon.
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