Reset / HDD activity LED

JohnB1182 · 07-10-2002, 11:33 AM

I want to make efficient use of the cable runs I have made in the car. I have the mobo in the boot, and the controls and a VFD up front.

I need/want a reset switch, HDD activity LED, power ON LED...etc in the dash.

Basically I want to know if I can replace the 6 or so wires needed for the LED's and reset switch, with fewer wires, by doubling up their function.

Can I get away with using the same ground for the HDD activity and power ON LED's, I should be able to ground them to the chassis up front, or is there a reason why they need to go back to the motherboard headers?

Can I use the same positive for reset switch and the power ON LED??

Would it be acceptable to touch the 5V rail of the PSU to the reset switch header, or would I live to regret it??

Has anyone put a PC speaker behind the dash or will I just get annoyed by it and end up disconnecting it???

I hope all that made sense, it did when I wrote it!

ShinkunoNamida · 07-10-2002, 12:34 PM

Use a lenth of cat5 and an rj45 connector (this is what is commonly used for 10baseT ethernet) It's very simple to do.. look at the photos on my website to see an example of what i did.

dug1967 · 07-10-2002, 01:12 PM

My two cents... Hope it helps....

I have computer box in the back and the LCD, ATX switch, Sound Control Knob in the front. Plus I have some ECM wires running from the front to the back.... and also a temp sensor and fan control wires from front to back....

I didn't want to run a bunch of wires, so I made a front header and rear header PCB and connected them with a 10 conductor ribbon cable. It worked good for me and drastically reduced the bulk of wires running from the front to back.

JohnB1182 · 07-10-2002, 01:43 PM

I had a reply typed out, but I turned my back for 2 second - and now it is gone.

Ah well, it went something like this.

I have already got 3 lengths of CAT 5 network cable installed.

9 cores to each if you count the unsheathed core that is free to touch the shielding.

I use 9 cores for 8 push-button switches to control the playback for Winamp using the COM port plugin.

I use 13 wires for my alphanumeric VFD display.

That leaves me with 5 wires.
I need 6 wires if I am to have a positive and a negative lead for the two LED's and the reset switch.

I want to avoid having to run an extra length of cable just for this single wire.
Although if I did put in an extra run of network cable, it would allow for future expansion, I have run out of cable.
If I can get away with using the existing wire, by using some of the cores for more than one function I will be happy.

Back to my original question. Is it specifically the two 'reset' header pins on the motherboard that have to be shorted to perform a reset? Or can I take advantage of any existing 5 or 12 volt wires that are already at the front of the car, to be ably to just have to run a single wire from one of the header pins?

Equally do the HDD activity LED and the Power ON LED, Header pins require their respective pair of header pins to be used, or can I just run a single wire from the positive side of each header, and earth the negative side to something at the front end of the car, to avoid having to run two wire back to the boot.??

Cheers for all you help so far.

I am now on the lookout for a stray length of network cable, wish me luck.
I don't know how I am going to fit the extra length in.

Shades · 07-10-2002, 02:01 PM

If my memory is right, the reset switch is active "low", so, for the LED and reset swirch you'll only need 3 wires, the POSITIVE LED the GROUND and the POSITIVE RESET

Conect the led to the POSITIVE LED and to the GROUND, and to make reset just short the POSITIVE RESET with the GROUND.

I THINK that the reset is active "low", so before you trust my word, verify if i'm not lying.

EDIT: and to the HDD LED, you'll need another wire, the POSITIVE HDD LED. All in all you'll need 4 wires total, if you have 6 to spend than thats OK

EDIT AGAIN: (forgot the power LED) the 5th wire, use it with the POSITIVE PWR LED.

JohnB1182 · 07-10-2002, 02:30 PM

Thanks SHADES

It'll probably be a week before I get round to trying it all out.

I was just not sure about the switches and LED's needing both wires.
If only a single common earth is needed for all the LED's, why don't motherboard manufacturers only put the positive header on the board, and then let the case manufacturers wire all the negative leads in a daisy chain, and ground them to the chassis. It would save both manufacturers time, money and space. Not to mention it would prevent retards like me connecting the LED the wrong way round.

Ahh well, I'll never change the world from here.

ShinkunoNamida · 07-10-2002, 02:48 PM

not all cases are made of metal.. not all boards are mounted in a case.. It'd be rather foolish for the mobo companies to leave it up to someone else.. in my opinion anyway.. what ever that's worth