Lefebure GPS

[mx270a]

This is a continuation of this thread:
http://combineforums.proboards42.com/ind....read=1190866762


Current status: Development, non-functional.

As discussed in the previous thread, I've decided to pursue building an auto-steer system for ag use. Actually, it is two programs in one, a GPS logging system (to log what you're doing and where you're at), and then making the system steer a tractor.

The core of the system will be any Windows 2000 or XP based computer. This could be a laptop, tablet PC, or an actual mobile PC designed to run in a vehicle. I'm coding in Visual Basic 2008 Express Beta 2, so the application will require the .NET 2.0 Framework. I'll use SQL Server 2005 Express to store the data.

For external control (like running the steering control), I'm planning to use a card known as the "fusion brain". It is a USB based device, 10 analog inputs, 4 digital inputs, and 12 outputs, all sitting on a card about 3 inches square. It runs natively on 12V DC, and the outputs are capable of running relays. I think I can easily adapt this to the steering control. The device costs $50. More information about it can be found here:
http://www.fusioncontrolcentre.com/Fusio....&products_id=28

Current status: The GPS Simulator is complete and generating NMEA codes just as a real antenna would. Speed and heading are adjustable. The NMEA codes are being processed, checksums are checked, codes are sorted based upon what commands are useful, and the data is being logged internally to a table which goes nowhere. I still need to make it talk to a real antenna, and I also have to make it display the data on a map.

I'm going to make this initial *non-functional* version available to the public to get some feedback. I tried to get the user interface as simple as possible, but if there is something I could improve, let me know. To make this run, you will need to have the .NET framework installed, at least version 2.0. If you don't have it, the application will tell you. It is available via Windows Update, or via the link below. Feedback Welcome


Screenshots, Prerequisites and the Installer:
http://lefebure.com/software/fieldgps/

-Lance

[smithih]

What will you be using for a display?

[mx270a]

Quote:What will you be using for a display?

Any computer monitor you want. If you're using a laptop or tablet PC, those displays will work. If you're using a mobile PC, then you get to pick your own display. In that case, you could get a touch screen of whatever size you like.

The only requirement is that it has a resolution of at least 800x600, but larger than that and the program will make use of the extra screen space.

-Lance

[smithih]

So the interface is going to be a touch screen (if one goes that route) OR a keyboard/mouse?

[mx270a]

Quote:So the interface is going to be a touch screen (if one goes that route) OR a keyboard/mouse?

Correct. The application (like any other windows app) doesn't know if your using a touch screen or a mouse to "click" things on the screen. It doesn't really care. Thats a function of windows, the app just accepts that you clicked on something.

I really don't see much use for a keyboard, other than it would be easier to type field names and such compared to an on-screen keyboard, but whatever. It is an optional component.

Assume for a second that you don't have a touch screen. In that case, you need a mouse. In a moving vehicle, a typical mouse doesn't work good because of the flat surface needed to run it. In this application, I'd use a touchpad since it has no need to move. This is the same thing that most laptops have (that 2" square pad you use for the mouse).

-Lance

[mx270a]

The large buttons and text are so it is easy to read in a vehicle while bouncing around. This also makes it easy to click the buttons with a touch screen, or click them with a mouse.

The black background is for visibility. High-contrast colors make it easier to read in bright conditions. Plus, the black background means less light at night. I'm used to the 9" screen in our 2388, and that has a white background with black text. At night, I see the reflection off the door and my peripheral vision keeps thinking it is a grain cart or something over there. A black background won't help all that much, but it's a step in the right direction I think.

-Lance

[olblue]

I like it so far! But I'm a little confused. If you could do this in the past couple weeks in your spare time during the corn harvest, does this make you extremely intelligent or does that mean that the manufacturer's would have us think it's harder to do than it is?

How soon before I can input NMEA into it? I get the error message com 2 doesn't exist.

[mx270a]

Quote:I like it so far! But I'm a little confused. If you could do this in the past couple weeks in your spare time during the corn harvest, does this make you extremely intelligent or does that mean that the manufacturer's would have us think it's harder to do than it is?

How soon before I can input NMEA into it? I get the error message com 2 doesn't exist.

Well getting live NMEA data into it won't do you much good as of right now, as there is no map, and no database to log it in. I don't have a real GPS receiver handy right now (I'll borrow one from a combine in a month), so I'm not concentrating on that right yet. I tried to make it do real serial stuff using an external GPS simulator app and a COM port loopback program, but alas, I gave up on that and just made my own simulator that should act more like a tractor would anyway. It doesn't turn instantly, and has appropriate and adjustable speed.

There is plenty of Serial to Visual Basic code out there, and I messed with it for a while. I found that it runs much better in a seperate thread from the rest of the app, as it waits for data. I was also having issues pulling lines of data, not just one character at a time. As I said, lots of code is out there to do this, so I'm not too concerned about it.

The latitude and longitude stuff is a little confusing, as there are several standards out there. Decimal degrees seemed the most logical, but the only formula I found to add a distance at a direction requires using radians. Then the NMEA format uses Degrees Minutes. So right now, the conversion goes something like this:

Decimal degrees -> Radians -> Add distance at a direction -> Back to Decimal degrees, To Degrees Minutes for NMEA, back to Decimal Degrees for logging it.

Yeah, I've been at this for just over 2 weeks now, starting from scratch, since I'd never used VB before. I'm now thinking about how to do the map (on a panel, or in a picturebox). That and the math for drawing a map of points is going to get a little intensive, especially if I try to redraw 10,000+ points on a map at 10 times per second. I haven't figured that one out yet, but gimme a week or two.

-Lance

[montana]

lance make sure you can turn your screen red so if you are operating at night your eyes don't get screwed up When I lived on a boat in Alaska I had a navagation system on my computer and if you were running at night i=you could turn the screen to be red and you could see the water really well in fact on my radio's vhf ect... could be turned to red lights really nice for night time whish my Insight and stuff could do this you can turn down the brightness but that is it. oh arn't you gona try to do the turnes for you 180 turnes or just 90?? good luck

[mx270a]

Montanna, its interesting you bring up the red thing. I believe it has been proven than red light is much easier to see at night than any other color. The gauges in a car are easier to see if they are red. Red and green are at different ends of the color spectrum, and at night our eyes seem to be able to adjust to/from red quicker than green.

I'm curious if the red theme in your boat was more important with water being around, like something to do with the moon reflecting off the water or something?

That said, it is just colors on a windows program. They can be set to anything. To change them "on the fly" is possible, but requires some code. I'll get to that later after I make the thing actually work.

The simulator turns in increments of 90 degrees. I think I can make the system steer a tractor in a U turn at the end of a pass, in which case it will do a 180 degree turn. The simulator and the Auto-U-Turn thing are two separate functions. Of course I need to be able to make it steer down an AB line first.

-Lance