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

Anyone interested in a couple of 80A isolators and willing to buy about $10 to $15 worth of parts and build either one?

The following circuits may be of interest. I designed these for my Car-PC. They are adjustable and easy to make. One is basically an 80A solid state switch. The other allows full charging of a secondary PC battery while “always” keeping it isolated from cranking voltages via a 35A diode, in other words it only connects directly when the alternator is charging and above 13v.

In my system I didn’t want to count on the M4-PSU low voltage programming to protect the main car battery, therefore one unit (80A switch) is wired as a low voltage cut-out to protect the main battery.

In an attemp to achieve glitch-free 100% reliable starting of the PC, PSU and various USB microprocessors controllers under all Vehicle starting conditions and aux battery state of charge conditions I built thse circuits and found this layout to work faultlessly, no moving parts and no heat when mounted on a small heatsink (Aluminum case.)


Part of my Car-PC wiring.

Clearer detail in this PDF.

BattConnections.pdf

Measured temps with the new system layout after 3 hours driving with a trunk full of luggage so almost no free air space in the trunk, outside ambient temp 27c (81F) .

The old case and system layout would have seen CPU at 42c (108F), MB 46c (115F) and M4-PSU 48c (118F). It would have been a big problem if the outside temp had been around 46 deg C (115F) in that confined space with no available air volume left in the trunk to circulate and cool the system. Temps are way below that with an empty trunk of course - lots of air to circulate.

New layout with no free trunk space, CPU: 26C (79F), MB: 28C (82F), M4-PSU: 27C (81F).

Climate control set to 26c.

Off track but anyone interested in the OBD-II HONDA Interface module for the Honda HDS might find this interesting. HDS (Honda & Acura Diagnostic System). HONDA/ACURA from year 1992 to 2009. The HIM comes with Honda diagnostic software for a PC.

The software is designed for a touch-screen and includes an OSK (on screen keyboard). I have tried it on Win-XP to W7 32 bit and 64 bit. I run 1024 x 640 on my 8” widescreen and I’m not sure how it goes on smaller resolution.

The HIM device was only available to the HONDA dealers and is the only OBD-II unit that can show all of the Honda propriety system information. Even the (expensive) Auto Enginuity OBD-II ScanTool with the HONDA add on software module cannot do the functions, Vehicle system setup-up and component diagnostics of the Honda unit.

It’s been said that these units (this one from Hong Kong ) are a knockoff of the original RERADYNE unit however I have my doubts, especially when you see what’s in these, how well they are made and the fact that internal Firmware would have to be reversed engineered to get these units to function.

The Honda device costs over a thousand dollars to purchase from official outlets, however this unit cost me $168 delivered to my door (price is now around $180 delivered). It payed for itself the first time I had a problem from an apparent electrical glitch that had caused an ABS sensor to go out of calibration. The Honda workshop manuals (which use the HIM in most of the repair and testing procedures) and the HIM with the supplied Honda software pointed to that as the most likely cause of the problem. There were special instructions to recalibrate the sensor using the HIM which worked as described. Without the HIM the dealer cost would have started at around $160 and gone up from there.

The information available on all vehicle systems and the diagnostics you can carry out is amazing, however if these advanced features are used without a full understanding of what you are doing you can easily cause damage to the vehicle.

IMHO this is the real Honda unit, I purchased another recently in case one fails or they become imposable to get. When you consider how complex a modern vehicle has become and the strange but simple problems you can encounter as they age, any of which can stop the car from running, it’s becomes cheap insurance, especially if you’re a Car DIY type and plan on keeping the vehicle for a long time.

The second unit (not shown) is a slightly later REV and has a single board with larger SM Micros. Both work exactly as the Honda Workshop manuals state.

How can one acquire one of these units? I'm quite interested.

-Zack
via Droid Charge

Here is the seller I used, there are others.

http://cgi.ebay.com/ebaymotors/ws/eB...AQ:MOTORS:1123


The seccond unit.

For anyone looking for a low cost service manual, various HONDA PDF Service manuals (fully indexed, hot linked and searchable) for around $22.00 each.

I have the original Honda workshop and V6 supplement manuals and I can confirm that the PDF is a full high quality copy of these manuals. I purchased the PDF for the Car-PC and desktop PC to save lugging out the big manuals each time I wanted to look up something.

http://www.automanualsource.com/

Or eBay/PayPal link.

http://cgi.ebay.com/ebaymotors/ws/eB...AQ:MOTORS:1123

I have been playing around with web cams and have two installed and running.

Results are great, a lot better than I expected thanks to a program called MiniCam, this makes recording a breeze and imbeds in my front end easily for multiple camera recording. I can have them auto start or start and stop them manually using either the steering wheel controls or my feDrive control.

I also added short voice announcements to the FE for camera selection and recording for “eyes on the road” safety. The feDrive home button now selects the Front camera if the main menu is showing and pressing it again selects the Rear camera, pressing again cycles back to the Main menu.

Rotating the feDrive control to the left and pressing stops recording on the selected camera, turning right and pressing will start a recording, that’s all done with the hand resting on the centre feDrive panel positioned between the front seats.

Steering wheel Channel Up-Down buttons also start or stop a recording on the selected camera. The steering wheel Mode button, as usual, cycles through each running app accompanied by voice announcements (if selected in setup) once again to avoid talking eyes off the road. I never had to use the touch screen once over the trip.



I tested everything over 4 days with up to 10 hours driving on one day. Garmin PC locked once over the entire 4 day trip buy my FE automatically detects that, kills any remaining GPC tasks left running and then restarts GPC in about 4 seconds total.

I just finished installing an optical input DSP unit between the Car PC and the amplifier. Not that I have a noise problem in that part of the system but I wanted to be able to tailor the system using the Graphic equaliser in the DSP unit and since the PC had an optical out I decided to use it.

One nice thing about this unit is the provision for an analogue volume control to control all four channels with a single control via an ADC input. It means that you could run a long 3 wire lead to the front of that car and fit a standard $1.20 volume control. No noise and simple to do.

I had already programmed an encoder to control an analogue pot via a stepper motor, it in turn adjusts the signals going to the amp via the analogue pot, but this DSP is better, so I replaced my multi-gang control with a single gang pot and plugged it into the DSP board, the encoder at the front of the car still controls the analogue mechanical pot connected to the DSP board ADC.

I also had a problem getting the PC Line input fed from the DAB-FM radio to go out the optical port, a Google search bought up lots of similar problems but no simple solutions, anyhow I decided to look everywhere in the sound setup screens and found the solution, talk about useless MB manuals and useless information about using the digital out port on a PC, all working now.

So here are a few pictures.

Some info on the MiniDSP and MiniDIGI.

The basic MiniDSP PCB has 2 analogue inputs and 4 outputs and goes up from there. Various software plug-ins are available to make this unit do just about everything you want. Most use this as an active crossover for a pair of two-way speakers. I coupled this with the MiniDigi PCB for Optical inputs which stacks on top of the MiniDSP and used this with the equaliser plug-in to fine tune the system.

MiniDIGI.

2 x SPDIF & 2 x Toslink inputs
Buffered SPDIF & Optical outputs
Asynchronous Sample rate converter
(ASRC) allows wide range of digital
signal (up to 216kHz)

Easily stack with MiniDSP series
SPDIF isolation transformers

Configuration switches
Source selection (1 out of 4 inputs)
I2S routing (Select 1xIN, 1xOUT)
Master/Slave selection

Power
Wide range of power supply voltage
from 4.5 to 24Vdc.
USB self-powered when used along
with miniDSP







Mixer Plug-in specs.

Sampling frequency 48kHz
Input mute Click-less input mute per channel
Digital gain Fader gain control from –80 to 0dB
Input RMS meters Monitoring signal from –80dBFS to 0dBFS - 150ms refresh
Low/High pass filters Butterworth/Bessel second order (-12dB/oct)
Linkwitz-Riley fourth order (-24dB/oct)
Bypass feature

Graphic equalizer 1/3 octave, 31 bands equalizer with +/-15dB boost

Channel linking, bypass, reset
High pass filter Types: Butterworth/Linkwitz Riley/Bessel / Bypass feature
Matrix mixer 2 inputs mixed to 4 outputs
Knob control gain from –60 to 0dB gain
Output mute Individual output mute
Master output gain Analog potentiometer control fader from –80 to 0dB gain
Output RMS meters Monitoring signal from –80dBFS to 0dBFS

UPDATE: I added a PC-CASE picture and some more info on the graphic Equaliser plug in to the last 2 posts.

Found an interesting problem with noise when the Line Input (DAB-FM radio input) on the PC is used with the PC Digital out.

When Line in is used in the normal way (Line out to Amp) the input gain is set to around 90%. When it’s rerouted to the digital output line by the PC, the sensitivity has to set to less than 10% for the same volume, on top of that there was now a noise at high volume between audio tracks and when nothing was playing. Turning the Line-In control feeding the digital output up to 100% allowed me to hear this noise really loud.

A test that should be carried out is to plug a cable into the Line-Input and short the audio in terminals at the end of the lead to different earth points around the case. Make sure it’s an earth point else you will blow the line input.

If shorting the cables to ground on the outside of the DAB-FM case causes substantial noise then plugging that cable into the output of a DAB-FM module just a short distance away is always going to cause noise.

Connecting the input wires to the case of the PC just 1” away from the Line-in jack created noise. The only place which produced zero noise was the shield surrounding the input jacks inside the PC case itself. (I have been down this road before)

1: The PC PCB is mounted inside a case (see pictures)
2: There is an earth lead soldered to the earth pad under the PC-PCB screwed to an earth lug.
3: The DAB-FM module has a short thick lead from its earth to the chassis.

4: Running a thick lead through the back of the case soldered to the PC input connector shield and to the shield on the DAB-FM radio almost removed all noise when the Line-In lead was shorted to the earth of the DAB-FM module (everything full volume).

When the Line-In was reconnected to the DAB-FM module there was absolutely no noise at the normal running input setting.

If you look at the large PC case I built you will see that the DAB-FM module is screwed to the same aluminium ground plane as the PC and the PSU, in other words a completely common ground plane. Both units already have a thick lead from their ground point to chassis ground to overcome any loss through the PCB mounting hardware.

Points of interest.

When the Line-In lead was shorted to the case of the M4-PSU (inside a shielded case with RF feed-through bypass caps on all leads) the noise was reduced considerably compared to the case of the PC.

When the case is taken off the PC the weak station performance of the FM radio is reduce.

When case holding the full CAR-PC components is opened (the lid is hinged and lifts up for quick access) the GPS receiver located at the front of the car drops 3 bars in signal strength- DAB FM are unaffected.

When you touch any USB outlet (you become a poor aerial) a DAB signal of 5 (good) can rise to 40 (almost no signal for dig reception), however GPS and FM are unaffected. That means that any web camera lead (and any lead) must be held against the car frame at all times. The front USB hubs are earthed to the car frame.

Consider also that the DAB-FM aerial is roof mounted. Its amplifier, at the base of the aerial, is powered by a lead running from the CAR-PC case in a loom with all other leads including Power and VGA. The DAB and FM leads also run from inside the CAR-PC case in the same loom. None of these leads or layout or the fact that the DAB-FM module is mounted inside the CAR-PC case has any affect on the receiver performance at all, this unit is the same as, or more sensitive, than a commercial radio in the car without the CAR-PC running.

It makes me wonder what ever possessed me to start on, what seemed like such a simple project, in the first place.

Anyway it’s all back in, and dam it works well – about #$%## time.

I have just a video of the thing working and a nice front panel to make and it’s finished.


Late EDIT:

I forgot to mention that, to my surprise, sound quality with digital out compared to analogue out is far superior, to the point that the door speaker quality (lack of) is obvious and really limiting the audio quality. I had expected there to be only a little change. It makes you question what goes on inside the analogue sound circuits on some MB’s. The really noticeable improvement is in the increased audio bandwidth, particularly the low end from the DAB-FM radio to Line-In, now being patched through the digital output in the PC, something changed drastically when this was done.

There has been no noise improvement, there couldn’t be, as there was absolutely no noise generated between the Alpine amp and the Line-out of the CAR-PC to start with, and now, as before, no noise between the MiniDSP’s four analogue outputs and the AMP.


EDIT for Clarification

Just to make it clear – The Mixer plug-in is NOT software that processes audio on the PC. It is a configuration and control interface for the MiniDSP board. It changes/loads firmware on the DSP board and that configuration resides there permanently or until you change it – no PC needed.

The Plug in software running on the PC is the control interface that talks to the DSP board, loads or changes a configuration on the DSP board and can control the DSP board in real time.