Interesting problem trying to extend ATX switch

InFix · 12-17-2002, 01:49 PM

Ive had a working setup for about a month now. The only catch is that I have to goto the trunk and touch the two wires connected to the mobo atx on pins (I actually just cut the connector itself from an old case I wasnt using, and just plugged it into the carputers mobo ATX on pins). The reason I have been doing this is because of a weird problem I encountered when I first installed the carputer. I used 24g speaker wire to extend the wires up to the front and connected them to a momentary pushbutton I bought from rshack. Here's the weird part. I could successfully turn on the computer if the ignition was set to ACC only, ie the engine wasnt on. Now if I turn the engine on, I cant turn on the computer with this extension. If I uncrimp the speaker wire from the two wires connected straight to the mobo (these wires are about 3 inches long, the speaker wire was about 10 ft long), it will turn regardless of whether or not the engine is on. I gave up on it for about a month, so Ive been popping the trunk to start the computer everytime I turn on the car, which is obviously annoying.

Today I decided to try this again. I figured this could be some type of interferance, and speaker wire isnt exactly shielded or anything. So I cut up about 10-12ft of some old CAT3 cable I had lying around. I followed the same procedure. Basically I crimped two of the CAT3 wires to the two wires coming out of the mobo. Touching the two wires successfully turns on the computer while the ignition is on ACC. As soon as I start the engine, same deal, it wont turn on the computer. I dont think this is interference of any kind because I had the CAT3 cable coming out of the trunk directly away from the car. I hadnt run it up to the front yet.

So anyone have any ideas? Popping the trunk everytime to start the computer is a pain in the rear!

CarComp · 12-17-2002, 02:26 PM

You might be encountering a "too much resistance" problem. I think that the computer puts out minimal amperage and it just may not have enough oomph to get the power to the switch and back. Couple that with the electrical noise that is inherent in a car environment and you have a problem. I suggest installing an "rca" connector onto you 3" mobo wires and another "rca" connector onto your switch. Put a shielded RCA cable (like what is used to connect amplifiers to head units) between the two. Those cables are made for low power and also low interference.

thenominous · 12-17-2002, 03:23 PM

I'd suggest that you connect a small relay to the motherboard's switch pins, and have the dash switch connect to the coil of the relay. You then have the facility of the dash switch, but the computer think's the switch is right on the pins. Save's running more cable.

Dave

danl · 12-17-2002, 06:22 PM

I experienced the "too much resistance" phenomenon (?) when trying to install switch to shutdown controller.
I used Pheonix Gold speaker wire to the switch and it worked for a time, then turned on and off by itself and did very strange things, sometimes nothing!
I then replaced this with bell wire from an electrical store which cost about £1 for 10m. It works perfectly. I'm sure there's a very scientific explaination but I don't care, it works now.
Merry Christmas by the way...

mp3z24 · 12-18-2002, 10:02 AM

ive heard of people using phone cord to wire their power and reset buttons in the car. it already comes with 2 pairs, perfect for the switches.

you may want to be sure that you are not running the wires in question near power wires. the power wire will overwelm the weak signals from the motherboard switches.

or using a relay would also work.

~mike

ShinkunoNamida · 12-18-2002, 10:12 AM

I used a 20ft length of cat 5 to wire to the LEDs and the switches on the mobo with no problem. Perhaps my mobo is different and that's not an issue.

maybe the crimps are making too much resistance?? Try using wire nuts.. or my favorite method "twist it together and tape it up with what ever is laying around"

Electronicsuk · 12-18-2002, 03:47 PM

Possibly picking up stray signals from somewhere? Would explain why cat5 works, you have twisted pairs to reduce EMI.
Best regards,
Matthew

thenominous · 12-18-2002, 05:55 PM

CAT 5 is the daddy of cables. You can extend everything with it.
I have a 25foot long VGA cable here with no picture problems at 1600x1200. A mate has a compositie video setup with four channels down the cable for around 50 foot.
Dirt cheap and damn useful.

Dave

timothy · 12-19-2002, 02:36 AM

Quote:

Originally posted by thenominous
CAT 5 is the daddy of cables. You can extend everything with it.
I have a 25foot long VGA cable here with no picture problems at 1600x1200. A mate has a compositie video setup with four channels down the cable for around 50 foot.
Dirt cheap and damn useful.

Dave

Just wondering: how many leads are there in a VGA cable?

jol · 12-19-2002, 04:37 AM

Quote:

Originally posted by timothy
Just wondering: how many leads are there in a VGA cable?

nine or fifteen I think, according to this.

I would use the relay solution, If that wouldn't work wire a lamp or something in series with the control-part of the relay, to make it draw some amps(dont use a 100w, just a small one

then youll also see if it clicks or not with ease

....or just use a relay

thenominous · 12-19-2002, 06:31 AM

Quote:

Originally posted by timothy
Just wondering: how many leads are there in a VGA cable?

My CAT5 is shield cable, and I use all 9 (the 4 pairs plus the shield) to do the VGA signals. Sync GND is the one connected to the shield.

Dave

CarComp · 12-19-2002, 07:02 AM

Above, there was a post about using a relay to turn the computer on. I am a retard. That is how I do it. I have no clue why I didn't just say what I do. Oh well. I know that works, plus if the relay is relatively close to the computer (3") you should have NO problems what so ever.

timothy · 12-19-2002, 04:17 PM

Quote:

Originally posted by thenominous
My CAT5 is shield cable, and I use all 9 (the 4 pairs plus the shield) to do the VGA signals. Sync GND is the one connected to the shield.

Dave

I have a big spool of some Cat5E and all I have is the four pairs, so thats only 8. I dont seem to have a shield like that.

I guess if I wanted to do this I would have to split open another wire and run it outside or something.

edit: oh and jol, thanks for that link. that site is very useful

thenominous · 12-19-2002, 08:11 PM

Ive got a big reel of unshield here too. I "borrowed" that cable from work to do the job. IIRC it doesnt work with 8 pins, but dont go quoting me on that.
I'd test it, but I hot glued the end of the cables together so they wouldnt bend or disconnect.

Dave

InFix · 12-19-2002, 08:40 PM

Cool guys, thx. I have plenty of different things I can try now

Im going to try cat5e first, and if that doesnt work, Ill go ahead and try the relay approach. Thanks again!