Coffeejolts: April 2008 Archives

So, I finally got navigation working right and then I notice this morning that the GPS receiver can't get a lock. I did a bit of Google-ing, and found some posts saying that removing the battery can fix this problem. I took the GPS receiver apart, only to find that the manufacturer glued the battery to the prongs.

Miraculously, after I put it back together, the GPS started working again. My guess is that it resets itself after a certain amount of time passes. The important thing is that it is working again. I'll keep my eyes open for new receivers in case this one dies again.

I upgraded the grounding point last night. Or, maybe I should say that I hope that I upgraded the grounding point last night. I had it grounded to the trunk pan, which was causing a lot of noise in the audio. So, I took out one of the bolts that hold the back seat in, sanded all the paint off of the surfaces, and grounded the system to that.

I couldn't actually test it last night, since my DC-DC power supply is still on its way back from Opus Solutions. I sent it back to them to have it modified because it was powering USB devices even when the car was turned off. The PSU should be waiting for me when I get home from work. I can't wait to hook everything up and see how it works now. I'm keeping my fingers crossed that my ground loop noise is gone.

UPDATE

Moving the ground point did help a little, but I still had some noise, especially when the computer read from the hard disk. I then tried re-routing the audio cables away from the power cables, which did not help at all. So, I finally broke down and bought a ground loop isolator. I don't notice any signal degradation, and all of the noise is gone. With this noise problem solved, I'm finally ready to build the trunk installation and post some pictures.

Here are the tasks I have completed on the car pc so far. I should have taken pictures to document, but I was in a hurry.

• Map pocket modified and installed.
• I took the map pocket apart and installed a hinge to mount the LCD to. I also drilled a hole in the back to route the power cables through.
  
• AuxMod installed
• I removed the stock head-unit and installed the auxmod module into it.
• Lots and lots of cable routing done
• Routed power, audio, video, and usb cables throughout the car.
• Installed distribution blocks for power / ground.
  
• USB hub installed
• All software installed and configured on the PC.
• Performed power button modification hack so that the PC turns on and off with the car, via the Opus PSU.

I went hunting for more information on Java Media Components, and found that there are two sessions scheduled for JavaOne that should shine some light on the new API.

https://www28.cplan.com/cc191/session_details.jsp?isid=296509&ilocation_id=191-1&ilanguage=english

https://www28.cplan.com/cc191/session_details.jsp?isid=296511&ilocation_id=191-1&ilanguage=english

I found a page documenting the tile naming schemes of the various online map providers today. With that information, and the JxMapViewer component from swingx-ws, I was able to hack together a Yahoo Maps mash-up in under an hour.

The code still has a bug in it: latitude / longitude do not translate correctly. The marker on the map should be placed on London. I'll have to do some more tweaking to see if I can finish this up. The code needed to do this is surprisingly short:

public class YahooMapFrame extends javax.swing.JFrame { TileFactoryInfo yahoo = new TileFactoryInfo(0, 17, 18, 256, true, true, "http://us.maps2.yimg.com/us.png.maps.yimg.com/png?v=3.1.0&t=m", "x", "y", "z") { @Override public String getTileUrl(int x, int y, int zoom) { int yp = ((int) Math.pow(2, 18 - zoom)) / 2 - y; String url = new StringBuffer(baseURL).append("&x=").append(x).append("&y=").append(yp).append("&z=").append(zoom).toString(); return url; } }; TileFactory factory = new DefaultTileFactory(yahoo); /** Creates new form YahooMapFrame */ public YahooMapFrame() { setLook(); initComponents(); mapKit.setTileFactory(factory); mapKit.setZoom(17); }