Time setting from GPS is a great fringe benefit, but the original idea here was to develop a simple interface for a generic GPS receiver to display Position, Velocity and Time. This would form the basis of a diagnostic capability for an Empeg/GPS system in advance of having the software for a full blown navigation system available.

I didn't mean to suggest a change in your focus. I was just thinking the underpinning of what you describe and that of my HH:MM:SS are very similar -- grab data, format, display. I saw it as an easy "come-along" opportunity. Also, I could see running a navigation GPS display like yours indefinitely -- it might be enough for me versus a full-blown nav system.

Once we have time available then using it to limit the drift of the Empeg's time keeping could follow. Not all receivers provide a discrete 1 pps signal and getting it into the empeg would involve "borrowing" another input, such as the Headlight Sense or Mute. By using the time stamps available from the serial data stream with a little bit of calibration we should be able to have time accurate to within a second.

You are right. Plus, once I think about it I'd guess there are other issues with 1pps like kernel/clock requirements.

Anything you would care to contribute to this cause would certainly be welcome.


My few achievements in life are due to, well, theft (of other folks documents, programs, whatever). I did poke around for developer info on RioCar.org before to see if I could grab a clue -- get a compile environment set up that would work. In this case I would tend to attack this from the app layer down. First thing I'd see if I could build something -- maybe stolen from viewer? -- that would throw dummy values up on the screen, then work out how to fetch those values (adding something like a heading "hold" makes that a bit more complex) , and consider the best way to get them (I'd still look at the feasibility of using something like gpsd -- I'm lazy!!)

I am setting up another Linux laptop that I hope to be able to use for stuff like this while travelling. I'm not sure how far I'll get and how fast (I can't explain it but my work is actually starting to get busy), but I am motivated to learn enough to produce something for my own amusement. The last programming I did was ~1995 in Clipper 5.3!

Not to discourage further discussion in this thread, but at some point if some of us are able to take the appropriate baby steps I suppose we could communicate off-line in e-mail?