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

A couple of weeks of auto sleep throughout the day and push-button hibernate when leaving the vehicle overnight and not a single failure to resume or suspend in either mode. The M4 has behaved faultlessly, what more can I say.

I have revised and finalised the power distribution for the system with some extra notes and sections highlighted in the hope that it makes it a little easier to follow for anyone still interested. I will attempt to describe some of the functions of this system if anyone is interested in the hope it gives someone starting their first build some food for thought.



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The aux micro circuit. This is located in the main PC-PSU case.

Here are some things I wished I had considered before I started my first build, it would have saved me a lot of time.

There were so many roadblocks that had to be overcome to integrate this PC into the vehicle. I just dived in at the start of the project and never really thought of all the problems to come. Integrating equipment that’s made mostly for a desktop PC in a home environment and a general user/nanny operating system like windows into a vehicle is really difficult. Some of the problems that needed to be overcome in this system are not normally associated with the simpler CAR-PC installations. Once you start interfacing and integrating into the vehicle systems it becomes a whole new ballgame.

There are two key words here, integration and reliability. My goal was to integrate this system so that it’s like an OEM installation, not only in the way it looks but in the way you use it and the way it operates. Someone who has never seen this system or the vehicle should be able to get in and use it instantly. It should just turn on with the car and there should be no special precautions or wait periods or times when you should or should not start or stop the vehicle (engine cranking) and NO stupid small text to read or tiny screen buttons for selecting an option.

There is however one optional button that can be pressed when leaving the vehicle and this allows me to hibernate the system instead of having it automatically suspend into sleep mode. This change was important to me as it conserves battery usage on short trips (low charge rate due to time) and when not using the vehicle overnight or for a day or so. Resume from sleep is under 2 seconds (although I now have a 3 second delay before the PSU starts) so it’s now an agonising 5 second wait before music is playing and the GPS or HVAC display is on screen; that’s still close enough to an instant on system for me. (Love GPS on 8” wide screen)

I have thrown some random thoughts together on some of the things I found necessary along the way. But first “ATWPT”, that’s my short hand for “At the worst possible time”.

1. Run a minimum of 8 gauge negative and positive cables direct from the battery terminals to the PC supply and Amplifier (4g if the amp is much bigger then 200w RMS.) If using an aux battery in the trunk then consider 4 gauge cables to the battery as you want every bit of voltage available to keep that battery charged correctly. Heavy cables are not just to carry current and reduce voltage drop but are a must if you want to reduce noise in the system.

2. A switch close to the driver to kill Power to the PSU. Used when the system acts crazy, locks or starts to reboot when it should not. The soft on/off control to the PSU IGN line is totally useless for this. There will come a DAY when any ATX-PSU – PC will lock or spit the dummy in some way and on that day it will always fail ATWPT (usually driving in heavy traffic when you need the GPS). But the chance of it happening is dramatically reduced if you have a means to stop it (Murphy.)

3. A separate on/off switch located on the PC case to isolate the PSU from the supply when working on the car, making mods and leaving the vehicle somewhere for repairs.

4. A simple physical button that allows you to Shutdown the OS if some USB device stops working correctly or locks, almost always happens ATWPT and usually while you are driving.

5. A real physical volume control. Seriously, it’s a motor vehicle, an absolute must and a complete deal breaker to any pretence of integration if there is none.

6. A hardware amplifier mute circuit or a mute relay at the amplifier input that’s normally muted (in the off state) and requires the FE to send a signal to un-mute it. No silly timing issues and no window sounds at start-up or shutdown, yes you can turn these off in Windows but it’s just another thing to do when setting up a new system or reinstalling the OS. Having the Hardware mute gated with the PSU power control also allows you to kill the PSU (if needed) and not have a massive thump run through the system.

7. If the PC is trunk mounted make and locate the PC case so that anything can be thrown on top or over it without affecting it in any way. If you have to worry about air vents, stuff in the trunk or the way the luggage is thrown in then it’s a pain and another point of failure.

8. Heat, you can bet that the day you have to load the trunk full of gear with a car full of people will be the hottest day ever. With the reduced volume of air in the trunk (luggage) any PC is going to run hot after a few hours unless you give some serious thought to ventilation for the PC. This PC draws around 28 watts without the front and rear drive recording cameras running and it runs almost cold, but on a stinking hot day with hours of driving and a trunk full of luggage, it could get way too hot for my liking. The new design and location means that this is a thing of the past.

9. If you’re like me and like tinker or add something new as it comes out or to upgrade as new and lower cost technology comes along (rather quickly these days) then ease of access and the ability to pull the PC, modify it and run it easily on a Test bench is important. You will be doing a lot of that in the early days of the build so make the thing easy to install and remove.

10. Make the PC case as big and as strong as you can. I know this is the complete opposite to the way a lot of users go, but it depends on what you are doing with the system. If it’s a complex system with a lot of integration then go big. I made the mistake of going small at the start. It was only after the 2nd frustrating attempt that I really thought about how to fit a big case in a small space and I managed to finally make and fit a BIG case into the trunk recess that actually took up less usable trunk space than the first two small units. It’s now a delight to work on, inspect or modify. I eventually realised that even low power equipment will get hot on a stinking hot day mounted in a trunk that has no air volume because of luggage. The new layout resulted in a strong case that isn’t even noticed when looking into the trunk and allows the trunk to be packed to the hilt with luggage without any thoughts of heat, blocking vents or damage to the PC.

A larger case allows everything to be contained on one common chassis (ground plane). Mounting items like the PC (in its own small shielded case) ATX-PSU, DAB-FM module, DSP module, external SSD and HDD’s, relays, big slow moving fans, custom IO controllers, filters, fuses, sockets that are big, strong and easy to undo, heavy wiring and a neat logical layout with everything easily accessible are all easy to do in a large case and make for a reliable unit that’s easy to remove, service and run on the bench.

11. It’s becoming illegal to touch a GPS screen (or any screen) while in control of a motor vehicle and the authorities have started rolling out traffic cameras over here to catch you doing it. How this is going to affect newer vehicles that come with touch screens for a lot of car control is going to be interesting.

Example: Mobile phones-Visual Displays- faq-newlaws.aspx What’s interesting is the laws pertaining to VDU’s (LCD screen) which is another reason why I have static (no moving visuals) and simple menu screens that only cover the standard vehicle devices when driving, although I wonder about my DAB display of song info – illegal I bet. Also looks like they are tightening up on the mounting of add on portable devices so they require manufacture approved mounting hardware. I guess having the LCD and PC integrated and looking like OEM may be the way to go if the laws keep heading this way. I wonder how long before they make it illegal to change the OEM Radio and Audio system. I have already locked out sub menu access when the ignition key is not in the accessory position.

This is my personal opinion on Touch screen control. I’m not preaching to you. These are just my feelings and observations.

When I first started the build, touch screen control sounded like a fantastic idea. But once I started using it, I found it wasn’t long before I started to add real controls along with a pushbutton encoder for selecting stations, song tracks and other FE navigation tasks and it soon became apparent that touch screen control of an “information screen” that’s used and viewed by the driver “while driving a vehicle” is a JOKE! NOTE: This has nothing to do with the quality of the touch screen control. It’s all about reaching, looking and being distracted whilst supposedly in control of a motor vehicle.

Physical controls don’t move, they are always in the same place and you don’t have to look for them, you can FEEL them. The Human body-mind gets used to their location and can find them without having to look for them. I can’t do that with a spot on a touch screen, no! Tactile feedback will not solve it.

This brings me to the point about real buttons to control the FE. This include correct integration of the steering wheel controls (if the vehicle has them) and if possible separate controls to select the Radio, GPS, Music and HVAC (in my case) systems, volume control of course and ideally an encoder for song or station selection without the need to take your eyes of the road. I also have GPS map zoom controlled this way and I use all the time. This system allows me to control everything from my feDrive panel between the front seats and/or via the Steering wheel controls. I have voice announcements when using the steering controls so there is no need to look at the screen to see the selected function IE. HVAC, GPS, Radio, Music etc, even the Dual zone temperatures can be adjusted with the steering controls with the driver or passenger temperature announced as I change it.

Interesting thoughts there Mick. I agree with a lot of them and had started to think about lots of them.
Shame about all those rules.. Makes it tempting just to buy a factory head unit.. So you can't get in trouble.. I find it interesting that you can use a GPS and also use a GPS on your phone, the difference being that you can't touch the phone even if it is mounted. Guess it is about the difference in UI..
The other question I had was you mentioned that your touch screen is basically useless Do you think a capacitive touch could turn this around a bit, using gestures and swipes to make things not as location sensitive on the screen? I am still keen to have a rotary encoder for volume and possibly a few other jobs but also keen to use swipes for some navigation of the UI.

Cheers

Hi again, the link I gave was just one of many and it differs between states, but you can’t even touch the GPS unit itself whilst driving here. Driving = anytime the car is on the road, moving or not. Parked at the side of the road is the only time considered to be not driving.

Another interesting point is that people have been booked for having a “portable PC” of any kind mounted in the car in view of the driver. The police claim - it is still “capable” of playing video or other visual media and is therefore illegal. Now we can scream to the high heavens that this is unfair and cite OEM integrated head units that have this capability (however they are supposedly designed to automatically disabled this when moving) but at the end of the day the problem we have is that we have to go to court and try to prove that it was not capable at the time we were booked. That’s a lot of time and money and chances are you will lose.

This totally sucks but that’s what is going on in a police state that is most likely coming soon to the place where we live and drive, if not already.

Back on track to our installs.

Originally Posted by stretch4x4

Do you think a capacitive touch could turn this around a bit, using gestures and swipes to make things not as location sensitive on the screen?

I really tried to convince myself that touch screen use “when driving” was not a distraction.

It just is – The problem is compounded for me because my screen is mounted in the OEM location in the dash centre console, up high and in a perfect viewing location. I’m 6’3” so I have to physically move and lean towards the steering wheel and then reach out to touch the screen. Besides looking at the screen to touch the right spot is not something I would really do while driving anyway.

I’m sure that using gestures and swipes to flip through simple selection screens will help overcome the "right spot" problem, I already flip through screens with the second pushbutton-rotary encoder (feDrive encoder) when I need to. But in the end it looks like one day even using gestures while driving is going to get you a nasty big fine.

Of course the reason the law is changing to limit this kind of visual interaction with these devices in the vehicle is that most study’s carried out come to the same conclusion; In most circumstances it increases the risk of an accident. But like everything to do with the “nanny state mentality of total control”, it’s going to far again.

Originally Posted by stretch4x4

I am still keen to have a rotary encoder for volume and possibly a few other jobs

Just as a matter of interest, you don’t even need a rotary encoder or any programming at all if you use something like the Mini-DSP that I’m using to equalize my system. Just a bog standard $2.50 control and a length of unshielded 3 wire cable, you can control up to 8 audio channels simultaneously if you like with these things using just that one control.

Hmm might have to research that, was planning on having 5.1 from the computer and controlling balance/fade via windows but that might make it easier..
Was going to use the rotary encoder to default to volume but when push down do other things. The exact combination of that I hadn't decided on..

Yeah that nanny state things sucks.. Same with tyres can't go more than x bigger.. The problem many are having is they can build it to the rules in their state but then travel into another state where the rules differ and you can stil get a find for having an unroadworthy car, even if it is in your state

Almost makes it not worth bothering by the time you please everyone..

Mickz,

Splendid job mate. New Honda models use a bus system called GA-Net, including yours I believe. A bloke with an Acura and OEM navigation set out to design a device to read the OEM touch coordinates and feed them to a PC. As it turns out, climate control, OEM navi, and some of the audio info goes through the GA-Net bus. He came up with a "bus sniffer" to hack the GA-Net. At some point he stopped, and a Russian dude by the screen name of Slden picked it up and finished it. He called his final product the GA-Net+. You can read all the details at www.angrycamel.com. I, myself have this box to interface my Honda Odyssey OEM navi with a carpc. Here is a youtube video that shows the GA-Net+ in a Honda similar to yours: http://www.youtube.com/watch?v=i8DgzXGgFcI. Here is a video of mine: http://www.youtube.com/watch?v=0UNQb09cFd0

Cheers,

DominicanJB

Hi, unfortunately my 2004 Accord does not have that as there is no navigation in this model.

The Nav unit itself may have GA-Net protocols but it was not an option here in AU until later models were released. It can be retrofitted but is a very expensive option and limited for what I want to use this system for. There are HI/LO speed can-bus available in this vehicle and I will be interfacing with that soon, however there are no interface commands to control the HVAC unit, only a few to interrogate some basic diagnostic data from that module.

The GA-Net+ works with both, navi and non-navi models. In fact, the video I sent you is a Honda with non-navi. The owner bougth a navi bezel to make it look like an OEM navi model. However, you're correct in that you need the can bus for the interface. My setup works great, but I'm having noise problem with the screen which causes it to flicker. I'm using the M2-ATX for power supply. As you probably know, it doesn't do a good job filtering noise. When I power the PC from the house outlet, the flickering goes away, and I get the picture perfect. My Russian friend suggested to power the M2 directly from the alternator to get galvanic isolation. Another suggestion was to use an LC filter. I'd like to hear your suggestion on this, but without using an extra battery.

Thanks,

DominicanJB

It’s interesting or is that frustrating? That almost every bit of info on the GA-NET interface from the Honda interface suppliers talks mainly about the NAV interface.

However, it’s a moot point really as the interface to the HVAC micro is really very simple and a lot less than the cost of the GA-Net interface. (Unless the price has come down to around $80)

There are differences in functionality between countries for the same model Accord but in the end the biggest pain is not the interface or control but relocating the HVAC control board in these models. There are US models, similar to the Accord and without NAV that have a smaller HVAC board and separate LCD display PCB that are connected and controlled via that interface, so perhaps that’s the model he used?

As far as the LCD goes, I would be verifying just where the noise in getting in. Apart from the supply line, it may also be getting injected into the video feed itself by a difference in ground between the PC – M2 and the LCD or some other means.

The power to the M2 should come directly from the battery terminals. I would imagine that you have the M2 either in the PC case or close to it. Filtering the supply Line to the LCD would be the first place to start and has solved a lot of issues with noise. Some LCD’s are more prone to this than others. I have powered mine from the M4 (a lot worse that the M2) and it’s imposable to get a speck of noise or interference to show on that monitor and it has 15 feet of cable that’s wrapped up with every other power lead in the car over that distance.

I guess the best place to start would be to power the Monitor with a small battery just to eliminate that as the cause before wasting time on filtering and lead relocation there.