Hi Everyone,
It's great to see a few pplz giving this a go - the results are very rewarding! I have been travelling a bit over the past few weeks so I have not been able to post updates or do much work on the car. I spent the last past weekend on the finishing off the install but have some tweaking to do.
Update: I found quite a few bugs in the method of starting the eeePC from the ignition and have build my circuit on a bread board to iron them out. Once I have everything working I'll post a circuit.
Take a look at this circuit as it is the basis for my power on design:
http://www.mp3car.com/vbulletin/user-innovations/75071-laptop-auto-power-turn-module.htmlThe first thing I found is that the eeePC does not always power up when you press the power button (eg. turn the ignition). I found that at the time you turn the ignition the EeePC gets external power at the same time the relay triggers the to turn it on. It would seem the EeePC has to have external power & stabilise for a second or two, before you try turn it on. I can also delay the external power so it is not powered until after the power button is pressed and this works fine. With this finding I used a resistor / capacitor (RC) circuit to delay the application of external power to the EeePC by 3 seconds from the time you turn the ignition. The timeline looks like this:
...|IGN ON|....
...|Relay PWR ON/BTN closes (1.5sec duration)|.........
............(wait 3 sec).........................................|Relay External PWR closes (duration = while IGN is on)........
Another RC circuit produces the 1.5 sec pulse that triggers the PWR button. This is a
parallel RC circuit (produces a pulse of x duration) where as the one controlling the external power is a
series RC circuit, which produces a delay. Google RC circuit for details. In the final design I will be replacing the RC circuits with a 555 (or 556) timer IC.
I also don't like the idea of having a relay across the USB port as in the circuit above. The first thing to note is that
you should put a power diode (1N4004 to 1N4007) across the +ve and -ve terminals of the relay as back EMF into your USB port might, and over time probably will, damage the PC. A better idea is to use an optocoupler to drive the relay on the USB port. The 5 volts from the USB port will drive an optocoupler, which provides electrical isolation between the EeePC and relay circuit, and the optocoupler will drive the 5 volt relay.
The second problem I have with the circuit above is that when the EeePC gets external power the USB ports power up for about 5 seconds. This open’s the USB relay and the IGN trigger never gets to power on the PC. Delaying the external power by 3 seconds solves this problem too.
I installed the magnetic reed switch into the EeePC and this is working great!. To trigger the reed switch I used a 12v solenoid (an electro magnet) from Jaycar. It's the type that does not have a spring so nothing moves when it is triggered. If you are wondering what a solenoid is they are used in many applications including car central locking to lock/unlock your doors.
Hey Joel: where did you get your Nokia MIC? I need something like this for the bluetooth hands free. Also try RomRaider from OpenECU - this is a pretty good package for logging / gauges etc. I must try EvoScan too.
Just browsing the plug-in section of Centrafuse and there are some pretty awesome pluging’s:
* TPMS is a tyre pressure monitoring system that shows tyre temp and pressure. CarMP3.com has the USB hardware for $350USD
* BOM weather maps (need's data connection)
* Sync tool for synchronising folders over a network. Keen to try it out - I am using SureSync right now, its a great package BTW.
* Garmin Mobile PC plugin - allows Garmin to dock nicely with Centrafuse and automatically presses the 'Agree' button on loading. Also has a great on-screen keyboard for entering addresses etc.
* Track/timing plugin which has maps of Sandown, Bathurst etc & a generic 1/4 mile. You can use this to time laps or do touring events.
* Scribble pad for taking notes on the run
I have also had some issues with WinXP hibernate. A BSOD from the bluetooth stack & the occasional crash coming out of hibernate. An external PWR switch is really a must in your PWR circuit above as there are times when you need to hold down the PWR button and hard reset the PC. A small price to pay for such awesome functionality tho.
I believe Centrafuse v3.0 (soon to be released) will run much better than v2.0 on WinXP Embedded (WinXPe). Im keen to try WinXPe if I have the time. You will need quite a bit of testing development with this as almost all the drivers are stripped out of WinXPe and much work is required to load them separately. This includes everything from Motherboard, SATA, bluetooth, network etc. If anyone is keen to go this path plz PIM me and we can work on this together hey! It will be no easy task.
A couple of things on the car install process. Have a think about what cables you need to run, before you embark on pulling the dash / console apart as you are bound to have it in parts a few times. For me these are:
* PWR to the PC
* IGN to the PC / Relay circuit
* Separate momentary switch to power / hard reset the EeePC
* VGA
* Audio to your MAC / Car AMP
* MIC from your PC to a spot above the drivers head for mobile phone / voice control
* USB: I ran 1 cable from under the drivers seat (where the PC is) to the console where the USB screen is. From here I installed a 12v powered USB Hub. This is because you need quite a few USB ports up front of the car. One for each of the following:
-- the Lilliput Touch Screen
-- Keyboard in the glove box
-- Tactrix OBDII under the dash
-- GPS which I installed behind the Lilliput in the dash (great location for reception BTW)
-- USB stick / IPOD access which I installed next to the cig lighter, behind the flip down cover, below the Macintosh.
On the EeePC itself two USB ports are used: the one mentioned for the above and another for the Relay PWR circuit.
I also ran an A/V cable to the Lilliput and put a socket in the centre console so I can plug in an Ext DVD player or Game Console later on.
Quite a bit of cabling so give it some thought & layout your cables on the ground before you run them. You can then loom them up - I used flexible PVC conduit to enclose all the cables to and from the PC to the dash. This will protect the cables and make the install professional & neat.
Under the drivers seat there is a small cut in the carpet (from factory) where you can pull cables out. I pulled the centre console out and used a coat-hanger to pull all the cables down from the console, past the drivers seat -under the carpet. I also found it useful to store in my electric seat memory a setting where the seat is far forward and another for comfortable seating. You will be moving the seat back and forth quite a bit to access & install the PC. With just 1 button press the seat moves fully forward & I can gain access to everything - pretty neat hey!