I bought a cheap web cam at the supermarket on the weekend. After plugging it in I wondered how hard it would be to program. Particularly, I wondered if I could programmatically take pictures with the web cam and send the pictures up to my weblog along with the GPS information that already goes there. I figure so long as I have a database of everywhere I have been, I may as well have a database of what those places look like. And it was a long weekend, and it seemed like a good project for a long weekend...

The easiest way I found to automatically capture images on Windows is to use the API in avicap.dll. capGetDriverDescriptionA lets me enumerate attached devices and return a device name, which I can then pass to capCreateCaptureWindowA to creates a capture window, which I can then hook up to the web camera using a series of windows messages (sample code here and here. Not elegant (why do I need to create a window to capture some video?), but it works.

That's the view from my couch, btw. For the moment I'm storing these in a DB via a SOAP service, but I wonder if there is a nice GPS + photos + google maps mashup in the offing...

Tags: programming

A while back I posted details of a little GPS program I built. The program is a Windows service that periodically takes my location (altitude, latitude and longitude) from a USB GPS device, and next time I am online reverse geo-codes the location and posts the result to my weblog via a web service.

After a while I noticed the location information was a little bit off. My initial reaction was that some sort of conspiracy was afoot, since Microsoft Street and Trips was getting the location perfectly well. Of course, it turned out to be user error. The NMEA data coming out of the device looks like this:

$GPRMC,215238.000,A,4737.2885,N,12219.4668,W,0.19,350.69,270107,,,A*74

I had taken this to be 47.37 etc degrees. It is actually 47 degrees and 37.2885 minutes. Solved!

Tags: programming