Pulse Voltage?

Lads,

I am in need of a pulse voltage, prefferably generated by the doors unlocking. The pulse is needed to start a power supply for a carpc.

I need to know if there is a voltage generated by the doors unlocking that can be used as a 'pulse' voltage and where to tap into said system to get the pulse from?

(by 'pulse' i mean a rise of voltage from 0v to 2-20V and back to 0V)

At the very least you might be able to pick one off one of the central locking actuator feeds. I would assume that they are a two wire arrangement with 12V on one wire and ground on the other to unlock and with the polarity reversed to lock.

I don't have a wiring diagram so I can't help much there for which specific wires in the loom to target.

A central locking/alarm kit may provide an aux output, what is the startup time for the pc? ie. from pulse to operable?

Interesting way to trigger the pc, but what if you just want to grap a jumper or something out of the car, you'll have to wait for the pc to boot up before you can lock the doors again to initiate the shutdown.

The PC will auto start as soon as power is applied. The pulse is to tell the DC-DC regulator to activate, supply the pc with power.

DC-DC reg will be constantly power from batt. it turns on and off with a pulse, so central locking pulse would be ideal.

Unlock = DC-DC reg turns on, PC auto starts (approx 20secs, hyber-->go)
Lock = DC-DC reg turns off, cutting power to PC and screen (which will already be in hibernate.

KINGCAB - Excellent point, but from what i am told and from the video i watched on the reg. It has start-up lock out and shut-down lock out. Meaning while it is starting up and shutting down the reg will ignore all pulses until after those events. Does that make sense?

Biscuits said:

KINGCAB - Excellent point, but from what i am told and from the video i watched on the reg. It has start-up lock out and shut-down lock out. Meaning while it is starting up and shutting down the reg will ignore all pulses until after those events. Does that make sense?

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Sounds like that power supply has plenty of features, the ones I've used in the past haven't been all that clever.

The xobyte (WOL) that I'm using, thanks to a firmware upgrade today, seems to be working OK. Although I had issues with motherboard compatibility, so I'm now using a eeepc.

Carnetix CNX-P2140 185W Dual Output Intelligent DC-DC Regulator.

This is the unit i will be purchasing come pay day.

mp3car.com

I'm hopefully downloading the D40 workshop manual as we speak. I will find that stupid pulse if its the last thing i do.

Mwwwah ah ah

Well, thanks to my new, D40 Workshop manual.

Found my pulse.

Biscuits said:

Unlock = DC-DC reg turns on, PC auto starts (approx 20secs, hyber-->go)
Lock = DC-DC reg turns off, cutting power to PC and screen (which will already be in hibernate.

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So each time you unlock the car the pc screen will come on or can you boot up/come out of hibernation with the screen off?

Each to their own but the screen coming on like that would bug the crap out of me, especially at night if I was just going back to the car briefly before returning to whatever else I was doing. The streets around here wouldn't be such an issue but buggered if I'd want to advertise that sort of thing in the middle of the night floating around St Kilda or the like. Then again I hate having the reversing camera screen on when reversing out of car parks at night so it's not suprising a live pc screen would bug me.

If it becomes a big deal. The dc reg has dual outputs and the second output can be set to ignition trigger only. I am most likely to run the screen off second output. I will know more when the reg arrives.

I'd be concerned about the voltage drop as the starter turns over the engine causing the PC to falter. You might need to put some sort of 12V buffering in that could last for say 15 seconds or so.

That is what the pulse is for. It powers on the dc-dc regulator which powers the computer. The dc-dc regulator is the buffer.