M2-ATX wiring question - ignition override?

**DaveB** · 02-02-2006, 09:08 PM

The M2-ATX has two power connections. J1 has power to it all of the time. J3 is connected to the vehicle ignition and I suspect it is only used for signaling that the vehicle is on -- J1 still is responsible for powering the M2. Correct?

I would like the ability to override the ignition-on. In other words, I want to be able to flip a switch and have the PC powered on even though the vehicle is not running. How do I do go about wiring this?

Do I set up a 2-way switch to the ign J3 and when I flip the switch to one side it gets power from the IGN and when I switch it to the other side it has power all of the time? This seems like it would take care of allowing me to choose if I want the PC to run with ignition or to run even though the vehicle is not running?

I see that there is an LED connection on the M2. I assume this is the power indicator. I do not see a hard drive activity LED connection?

**snova031** · 02-02-2006, 10:02 PM

You can wire the ignition wire on the M2 to a toggle switch going to constant 12v..

**caduceus** · 02-02-2006, 11:33 PM

Dave,

Get a 3 position, center off, SPDT switch (like Radio Shack part 275-654). Hook the center pole to your shut down controller's ignition jumper. Hook the top pole to constant 12V, and hook the bottom pole to IGN 12V power.

Now you have a handy "valet switch."

Flip it up when you want it always on. Good for keeping the PC on when the car is off, like stopping at the gas station, using the PC when parked, etc.

Flip it to center when you want it always off. This is good for short trips, valet parking, etc., when you don't want the PC on.

Flip it down when you want it to work in the normal fashion (PC on when car is on, PC off when car is shut off).

Hunt around the forums, there are some diagrams for this somewhere.

=caduceus=

**piabu** · 02-02-2006, 11:42 PM

If you forget and leave the switch in "ON" position, wouldn't that drain your battery? At least until the low-voltage shutdown (if present) cuts out, shutting your computer down hard.

Is there a more graceful way to handle this scenario?

**DaveB** · 02-02-2006, 11:48 PM

Originally Posted by caduceus

Dave,

Get a 3 position, center off, SPDT switch (like Radio Shack part 275-654). Hook the center pole to your shut down controller's ignition jumper. Hook the top pole to constant 12V, and hook the bottom pole to IGN 12V power.

Now you have a handy "valet switch."

Flip it up when you want it always on. Good for keeping the PC on when the car is off, like stopping at the gas station, using the PC when parked, etc.

Flip it to center when you want it always off. This is good for short trips, valet parking, etc., when you don't want the PC on.

Flip it down when you want it to work in the normal fashion (PC on when car is on, PC off when car is shut off).

Hunt around the forums, there are some diagrams for this somewhere.

=caduceus=

Caduceus,

Thank you, sir! No need for a diagram. That makes perfect sense. Very clever. I appreciate the response! I'll pick up the switch tomorrow.

Dave

**DaveB** · 02-02-2006, 11:49 PM

Originally Posted by piabu

If you forget and leave the switch in "ON" position, wouldn't that drain your battery? At least until the low-voltage shutdown (if present) cuts out, shutting your computer down hard.

Is there a more graceful way to handle this scenario?

You could remote locate the power LED to your dash and that might help you to not forget.

My truck has dual batteries. I have a hunch it could run the PC for a week!

**RawsonDR** · 02-03-2006, 02:37 AM

Originally Posted by DaveB

I see that there is an LED connection on the M2. I assume this is the power indicator. I do not see a hard drive activity LED connection?

Does your M2 have a hard drive? The hard drive activity LED jumper will be on your motherboard as usual.

Originally Posted by piabu

If you forget and leave the switch in "ON" position, wouldn't that drain your battery? At least until the low-voltage shutdown (if present) cuts out, shutting your computer down hard.

Is there a more graceful way to handle this scenario?

I don't really understand this. The M2 is made to gracefully control powering your computer. The switch comes in when we want to have discrete control in lieu of grace.

But if you want to keep the safety net up, you could just delay the off signal instead of eliminating it I guess. A timed relay, or use jumper mode 6 which waits 30 minutes before telling the PC to shut off (but never hardoff).

**bridoc18** · 03-02-2006, 01:37 PM

Will this setup work for the Toggle switch and the M2 board

**wishbone** · 03-02-2006, 02:22 PM

Originally Posted by bridoc18

Will this setup work for the Toggle switch and the M2 board

No. All power should go to the "switched" power on the PS. 12v constant should always be constant on the PS. If you set it up that way your unit would never turn on because it would either get 12v to the constant PS lead or 12v to the ign power lead. That's if we're still talking about the switch mentioned earlier. The switch mentioned earlier has ONE output. So that one output controls the switched power line on the PS, it doesn't touch the constant power one.

It's not that you couldn't do something like that, but I don't see the point unless you wanted a hard disconnect of some sort of the constant power. If you want that you'll need a different switch or possibly at least two switches.

**bridoc18** · 03-02-2006, 02:30 PM

Originally Posted by wishbone

No. All power should go to the "switched" power on the PS. 12v constant should always be constant on the PS. If you set it up that way your unit would never turn on because it would either get 12v to the constant PS lead or 12v to the ign power lead. That's if we're still talking about the switch mentioned earlier. The switch mentioned earlier has ONE output. So that one output controls the switched power line on the PS, it doesn't touch the constant power one.

It's not that you couldn't do something like that, but I don't see the point unless you wanted a hard disconnect of some sort of the constant power. If you want that you'll need a different switch or possibly at least two switches.

Could someone do an example of this in paint for me?