Thread: 2004 Honda Accord, Dual Climate Control, interface and Car-PC Touch screen control.

NO GPS reception?

This morning I when for a short drive only to be confronted with no GPS Speedo in my FE and no GPS signal on Odyssey Navigator. There are two different GPS receivers in the Vehicle, one in the front which has a selectable 1Hz, 5Hz or 10Hz update speed and drives the FE Speed indicator. The second is in the rear and drives the Navigator APP. Both showed absolutely no GPS signal.

I have a standalone GPS but it was in my Wife's car when this happened and would not be available for a few hours. I had removed the CAR-PC the day before to test a few SW update on the bench and my first thought was some crazy interference and perhaps I had left an earth off or something equally silly, anyway I switched to the DAB-FM radio and had perfect reception so I ruled out interference.

Connected one GPS RX to a 20ft extension and placed it far from the vehicle and I suddenly had a few satellites. Move back to the vehicle and they disappeared.

I decided to wait a few hours until I had the Standalone GPS in my hands and that's when it got really ridiculous. Full strength on the Portable Garmin GPS in the open, moved it into the Vehicle (PC OFF) and placed it on the DASH, still full signal. PC was turned on and the M4 PSU started, still full signal, started loading windows, still ok. Desktop came up and the signal went to 0 - absolutely nothing.

I'm sure it was working the previous evening, racked what little brain I have left and vaguely remembered that I had changed the Display refresh rate from 60HZ to 70Hz earlier on in the day. Switched it back thinking I was grasping at straws, as soon as I hit the accept button I had full GPS signal back! WTF!

By this time it was getting dark, tomorrow I'll see if it's the HDMI cable / signal, the Screen (doubt it) or the HDMI to VGA convertor in the front of the vehicle (likely suspect). Makes you wonder how we ever get GPS to work in the first place, keeping in mind it's been working for around two years without a problem once the M4 was modified and a crappy camera with a tiny SMPs was removed. Both had initially killed GPS and DAB-FM reception. Amazing how DAB was unaffected this time, must be an interference harmonic right in the GPS band.

Today I tried to find the source of GPS interference but it was initially hard to pin down. Using a hand held GPS it appeared to originate from inside the System cabinet.

FYI the other change to the system the day before was an updated Graphic control engine, which is why I had been playing around with display resolution in the first place. It has a lot more options and is really nice to use BUT something has changed, and now HDMI cable or MB is bleeding a carrier / interference way up into the GPS band, DAB and Mobile Phone modules (inside the system cabinet) are totally unaffected.

If the LID of the cabinet is raised slightly, hand held GPS signals drop to 0, even with the Display refresh rate set back to 60Hz. I noted somewhere way back in this thread that the REAR GPS would lose GPS signal whenever that main case lid was lifted.

As a refresh, the main case is constructed of PLY lined with aluminium sheeting, when closed it's completely sealed (aluminium walls overlap) except for fan enter/exit and a cable entry point. The hinged lid is bonded to the lower section with flexible copper strap. Inside the case is the M4 in an RF shielded case, PC/MB in a metal case, DAB module, Phone module, Optical DSP processor and various other devices.

I have a 6" 4G earth strap running from the System case to the Vehicle chassis (perfect dedicated chassis connection). I decided to change this to something closer to 0G. I added another 4G strap to bond the hinged system cabinet lid to the lower cabinet and retested the system. I'm surprised at the big difference those two changes have made. I now have good reception at 75Hz refresh rate, however its perfect at 60Hz so that's now where it stays. Also the GPS receiver mounted about 6" from the LCD screen does not loose reception now when running at 75Hz, the problem is not the screen or the HDMI to VGA convertor, it's definitely coming from the system cabinet mounted in the trunk.

BTW, clamp on ferrite filters placed on the HDMI cable made no difference as all and AFAIKT the interference is coming from the MB with a small amount leaching from the system case via various USB, control and 12V power cables. The main source seems to be radiating straight from the connection at the MB and the main aluminium cabinet case. Extra bonding seems to have quietened it down considerably.

Small update:

Finally moved the Win-8 64 PC from the test bench to the vehicle.
Everything works perfectly in Sleep, Hibernate and Hybrid sleep.
Boot time is still the same (14 seconds) with all USB devices.
Boot time has been halved compared to the Previous model MB running Win-7 64.
Metro not a problem and actually put to good use as neat TS friendly OS app launcher when needed.
Every USB port on the PC is used.

USB Devices:

BlueTooth (removed) now built in to the new MB.
WIFI (removed) now built in the new MB.

Front HI-DEF Webcam.
Rear HI-DEF Webcam.
GPS RX for SAT NAV.
GPS RX for Speed and Auto Sound Level control with1/10 second GPS update.
Dedicated (built in) Car PHONE Module.
Phoenix Echo cancelling MIC controller.
DAB-FM Module with Slide Show.
Optical DSP Audio Processor.
Hardware Volume Interface and Fail Safe Shutdown Micro controller.
Touch Screen Controller.
HVAC interface Micro controller.
Vehicle electrics Interface controller.
OBDII.
M4 -PSU interface.
Emergency Micro Keyboard RX.
Emergency Micro Mouse RX.
3 port HUB in the PC enclosure.
4 port powered Repeater (behind dash) HUB at the front of the vehicle (5M cable)
10 port powered HUB (behind dash) running off the above HUB.
5 port powered HUB (under ash tray lid) also running off the 4 Port HUB.

Speed Control of Volume via Breakaway.

I use Breakaway as my real time DSP volume leveller and finally got around to coding the GPS speed data to control the master volume control in Breakaway. Absolutely perfect with seamless adjustment of the volume with Vehicle speed. Should have done it years ago!.

What motherboard are you using now?

In my Sig

GA-Z77N-WIFI, i5-2400S, 8GB, Intel 520 128GB SSD

A Link to some info about the MB.

http://www.mp3car.com/software-and-s...oot-times.html

I just started a build page for my car. And was trying to read your work log... Very informative. Although I ended up just scrolling through a lot of the stuff I won't remember in 5 minutes anyhow..

Since I have the same motherboard as you I would like to know more information about your DSP unit, the microphone and how you were able to get your machine to boot up faster? Are there settings in the bios to speed up the boot up?

I am using an SSD for durability and reliability issues in my vehicle especially for cold weather over a spinning disk more so than for speed.
What kind of DSP unit should I be looking for because I love what you are doing with yours? I won't really need it in my car but certainly when I move it to my truck.
Also about the microphone, are you just plugging it into the rear port on the computer? I am considering a noise canceling mic like the one this site sells. But I will be looking into voice recognition and some other things. Still debating what I want to do for connectivity. If I run video like you are I will likely have it setup to download the data to my server when at home but otherwise loop through.

Also when talking about Micro Processors do you have any experience with the Parallax Propellers? I just picked a learning kit up for pretty cheap and I will be probably picking up a couple more of their learning packages to get a good grasp of what I can do with it. This powerful 32 bit processor comes with 8 cores and can do a lot. It is supposedly much more powerful than the PicAXE and some of the other similar microprocessor systems out there.

In my truck I expect to offload a lot of the processing for things to microprocessors such as the propeller and other computers such as a Freescale quad core arm processor. This way the PC won't have to be off looking at things but can access the information as if it had been. Another nice thing about using microprocessors is that they can run with very low power when the vehicle is off. The ARM processors such as this one can slow themselves down to a point they can sip power in a sleep mode and pull up to full speed at any time. I am trying to learn more and although I won't be a full blown EE when I get through with school I am supposed to be able to build simple devices and program them. It is very interesting reading what you have written. I plan to make extensive use of the ARM processors when I decide to start processing video since they have video processing capabilities onboard with GPU's. So things such as stereoscopic recordings and such become an easy reality.

But I certainly appreciate the detail and all of the information you have placed here.
I will also mention at this time I am hoping to be one of the team members writing OM when I have a little more time and projects like some of the ones you have will be interesting.

Another thing about using the full function microprocessors is that it makes it much easier to make systems in your vehicle work when the PC is off like your HVAC system. Although in your HVAC system it sounds like you are just pulling information from it and controlling it with your PIC chips and not trying to actually just use them as interfaces so it will work with your PC on or off.

Another question for you, with the more powerful MicroProcessors out there like the Propeller able to connect and communicate easily with a PC in many different ways have you considered restructuring your system to minimize USB usage? I ask this because I am thinking that it would be nice to have these specialized processors throughout the vehicle networked together with only one entry point to the PC but could be connected to multiple ARM processors or whatever you want to do. The Propeller chips can have a single wire network running very quickly. Or multiple wires for that matter if speed is more important. I ask this because I am considering making modules for all of the separate features such as ODBII, GPS etc and link them all together so they can be controlled better and have a single "switchboard" to the PC. With the ARM processors taking advantage of the Wired LAN to send any data to the PC as needed.

But reading your build log gets me more excited about my own ideas and lets me know they are not so crazy...

Ps, Sorry about the long posting. I seem to have an issue with being concise..
Rodney

Hi Rodney, no problems, just a few quick points as I'm on my out again.

I use the Mini DSP for three main reasons. 1: Optical out from the MB. 2: Equalisation independent from the PC. 3: A single unshielded 3 wire connection to control the volume. There are other ways to do this with some really nice USB high quality sound interface modules.

When you get to the Phone module you will see the Echo cancelling processor I used, these are also often used for Speech control via the microphone.

The Boot time of 14 seconds is standard for this MB, I have two and a friend has one that's slightly faster, exactly same setup but I used a stop watch, he didn't.

I use PIC micro Microchip controllers and program in assembler. These micros can run their own OS and are completely stand alone. They are using only a fraction of their capability to control what I need to do in the vehicle. The PicAXE is based on the lower power Microchip devices and has a Basic interpreter.

HVAC: You cannot write a "full climate control" system for a Vehicle and make it work correctly. A simple Air-con control is another story of course.

If you read the start you will see how involved it was trying to find a way to control the HVAC micro controller in the Vehicle and even to find a way to interface to it. I had to pull the data stream I found apart with a Storage CRO and figure out a way to decode, it is a non standard totally undocumented "In House" Honda system. No circuits, nothing!

The HVAC interface Microcontroller I programmed decodes this data, sends it to the PC and independently allows me to control the HVAC without the CAR-PC when needed. The power consumption is so low that it's not an issue for me.

As far as doing away with USB, In my case I can't see any reason to do so. Only ONE cable to a repeater HUB in the front of the vehicle is needed for 14 available ports. In any case most devices like WEB cameras, DAB radio, GPS receivers are purchased over the counter as USB devices so they will always stay that way until another standard comes along, I would never use something like BT in its current state for multiple devices in the vehicle.

BTW My Front End has changed a lot from some of these early picture, looks really great in the vehicle and complete system performs faultlessly. Again you can spend so much time on this kind of thing that it will never end. If I was young and getting involved in this right now I would likely make an elegant solution and use a form of CAN network. But it works 100% and it's easy to swap in a new device as it comes along or upgrade when the feeling takes hold.

Mike.

impressive, highly technical build!