I have to give more kudos to SparkFun. Despite their website saying they were going to be closed until Monday, the order I placed on Wednesday went out yesterday. Should be here soon.
In the meantime, I’m gathering the other parts and figuring out how to get them to interact. Here’s what I have so far:
The Arduino Pro board, I’ve already discussed. The camera is Cheap Cam, which I also mentioned last time. The GPS is an old Garmin eTrex. Not the most sophisticated of GPS units. However, it’s got a pretty cool feature. You can set it to send out text information once a second. It has a proprietary connector on it. I can’t remember why, but I ordered the cable shortly after buying the unit. I don’t think I ever used it, though.
This is the connection point and the connector.
When hooked up, it sends out a string of text once a second. The text is unformatted, so you have to know how to read it. A typical output looks like:
@081130052641N6450799W14749435g076+00194E0000N0000U0000
What does this mean? Let’s take a look at it a section at a time.
| @ | Signifies the start of a new line |
| 081130 | The date in YY/MM/DD format, so November 30, 2008 |
| 052641 | The time in UTC formated HHMMSS or 5:26 and 41 seconds UTC |
| N6450799 | Latitude position – North 64° 50.799 |
| W14749435 | Longitude position – West 147° 49.435 |
| g | Position status – g equals current 2D GPS position |
| 076 | Horizontal Position error, in meters. I’ll never claim my GPS, when sitting in my window, is horribly accurate. |
| +00194 | Altitude above sea level. A minus would indicate below sea level. |
| E0000 | East/West velocity. Traveling East at 0 meters per second. |
| N0000 | North/South velocity. Traveling North at 0 meters per second. |
| U0000 | Up/Down velocity. Traveling Up at 0 meters per second. |
Not shown in the table or sample text is that each line ends with 0×0D (carriage return) and 0×0A (line feed). Each section of the line is a specific number of characters long, making it pretty easy to parse. If a value doesn’t use the length of the section, it’s padded with 0’s, such as the altitude and velocity fields.
I suspect it’ll be fairly easy to tell the Arduino program to capture this data and output it in a usable, easier to read format. It’s finding a way to store that data that’s gonna prove more interesting.
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