Jayco-New carputer controller design

**jayearl** · 06-14-2006, 11:50 PM

My carputer project has been a cluster **** from the very start. I have managed to piece together what I need to make things work, but it has turned into something that would make even the most hardend proto builders shake their heads in disgust.

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Something had to be done. I have been working on a new controller board to consolidate many of the individual components that make my laptop work as a carputer, into one primary controller board to handle all functions.

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It is OOPIC based, and way overkill as it stands, but I wanted expandability to add any new functionality that carputer folks may dream up, and I may want to implement.

I have not finished final design (or cleaned up the layout) but what I have for functionality right now is:

POWER
12VDC to 19VDC- laptop power supply (3 amps)
12VDC to 5VDC- 5v power for logic and external sensors
12VDC to 7.5VDC- 7.5v power for USB hub (2 amps)

CONTROL
Laptop power switch and lid switch control to invoke hibernation and power off
Touch Screen power control
USB peripheral power supply control
Laptop power supply control
Radar detector mute control

SENSE
Radar detector output
Temperature sensors
Serial wire steering wheel control buttons
Analog sensor outputs
Digital sensor outputs
Backup camera reverse sense

I am getting ready to have the boards built but I was wondering if I am missing some key features?

**meddler** · 06-15-2006, 02:18 AM

If it's an issue, you could also look at amplifier control to stop speaker pop.

**jayearl** · 06-15-2006, 08:02 AM

Originally Posted by meddler

If it's an issue, you could also look at amplifier control to stop speaker pop.

Good call. It is an issue.

I have been meaning to add a IO line for that, but I had forget.

Its in there now. Thanks.

**jayearl** · 06-16-2006, 09:47 PM

I am looking to add OBD II to the controller and the elm327 translator seems to be a good good solution covering many protocols.

Any other recommendations out there?

**turbocad6** · 06-16-2006, 11:15 PM

does that thing need a regulated 12v? might be nice if the regulator was built in so it can accept raw battery power from the car... what about voltage drop & surviving crank?... if these were ironed out & produced it'd be a big help in installing laptops, which is a great way to install a carpc I think... I want one

**jayearl** · 06-17-2006, 10:02 AM

Originally Posted by turbocad6

does that thing need a regulated 12v? might be nice if the regulator was built in so it can accept raw battery power from the car... what about voltage drop & surviving crank?... if these were ironed out & produced it'd be a big help in installing laptops, which is a great way to install a carpc I think... I want one

I don't have regulated 12v now and I don't seem to have any issues.

The laptop survives cranking since it automatically switches to laptop battery power if/when the charger power goes away.

I have built in time delays in the OOPIC code so when the ACC line changes state it waits before doing anything and keeps monitoring the line. That way it doesn't tell the laptop to go to hibernation or shutdown after seeing short transitions from turning the key to a new position, or voltage drop from cranking.

That said, I could add regulated 12v if there still seems to be a need for it.

**jayearl** · 06-18-2006, 10:58 PM

Decided to add OBD II based on the ELM327 translator. What a pain in the arse for all the different interfaces. This over doubled the board complexity.

In the process of adding OBD I thought it would be best to upgrade to a USB link rather than rs-232. Now I just have to buy a USB license.......
Or maybe not.

Also incorporated amp anti-thump thanks to the meddler reminder.

**turbocad6** · 06-18-2006, 11:28 PM

looks pretty slick... the reason I mention regulated & surviving crank is I've been playing around with using laptop motherboards as carpc's & I've been planning on not including the battery to keep the case as small as possible.... I know a carnetix should survive crank & run off an unregulated input, just wondering if yours is kinda like that? be much more versatile if it could be...

**jayearl** · 06-18-2006, 11:44 PM

Ahhh, Good point.

My design would be a problem running the laptop without a battery! I have always considered the laptop battery as one of the luxuries of using a laptop with its built in power switching/conversion.

I will have to put some thought into this.

I don't know how most laptops behave when charger power in drops below 19v and there is no battery. I will have to investigate.