Carputer small power up/down, schematic review

denpo

Carburated Nihilist
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In order to have my onboard computer nicely integrated, I need a device to smartly boot up/shut down the computer.
I design it based on an ATTiny microcontroller. 8 pins (1 gnd, 1 +5v, 6 I/O).
I'm using all the I/O pins, 3 input, 3 output
1 input to sense the car ACC +12v, to know if the car is on or not
1 input to sense motherboard +5v, to know if the computer is on or not
1 input to a switch to force the computer in off mode
1 output to a relay that simulates the motherboard on/off button
1 ouput to a relay that controls motherboard power supply
1 ouput to a realy that controls the optional amplifier power supplier (to avoid pop sound when the computer boots up)

I will connect a 3 state override button, with auto/always on/alway off mode.
So here is the current design, with single side PCB (that's a PITA to make)
I'm looking for any comment on the current design before I start etching a board.

smallshutdown3_zpsbf306ab0.jpg



smallshutdown1_zpsbcd37529.jpg
 
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Ok, I realize now that was a bit silly to ask you to comment on the previous schematic, it was a mess.

Here's a revised revision, I hope people with electronic skills here can read

shutdowncontrollerschematic_zps2dd6d790.png


I made several modification :
the 12v sensing is now handled by an optoisolator to protect the microcontroller.
Also, the switching of the 12v source are moved outside the board, I just keep the 2 pin to connect to the activation side of an external car-class 30a relay.
 
I ASSume I am missing something, just what are you trying to accomplish with this seemingly extra stuffs there ????

Off hand it strikes me as department of redundancy department.....

:friends::crutches:
 
I ASSume I am missing something, just what are you trying to accomplish with this seemingly extra stuffs there ????

Off hand it strikes me as department of redundancy department.....

:friends::crutches:

Simply putting the +12v acc to feed the computer wouldn't work, the computer could never shutdown nicely.
Putting the computer on the +12v battery would require me to manually switch it on/off.

There is a lot of wrong scenario I can prevent :
-trying to switch it on while it's shutting down
-trying to switch is off while it's booting.
....

I just want it to behave like a modern car computer behave.
 
what about a relay hooked to 12v batt with a timer (or capacitor?) that will hold the relay on after ign is shut off for a predetermined amount of time?

just re-read your last post... didnt see the boot and shutdown issues so my idea wont work. I knew it couldnt have been that simple
 
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I'm guessing that you've:
already checked out MP3Car for some ready made products
enjoy the build - Seen that before :)
Have specific requirements that don't make the off-the shelf viable
enjoy the build - :)

Looking good! :drink:

Cheers - Jim
 
I ASSume I am missing something, just what are you trying to accomplish with this seemingly extra stuffs there ????

Off hand it strikes me as department of redundancy department.....

:friends::crutches:

Simply putting the +12v acc to feed the computer wouldn't work, the computer could never shutdown nicely.
Putting the computer on the +12v battery would require me to manually switch it on/off.

There is a lot of wrong scenario I can prevent :
-trying to switch it on while it's shutting down
-trying to switch is off while it's booting.
....

I just want it to behave like a modern car computer behave.

Even my old mid 80's-early 90's over 20 y/o speed density computer setup in my shark don't seem to mind being powered up with the ignition switch....there is once variation though, my injectors stay hot all the time, maybe one other power wire into the computer, that keeps the memory alive drawing near 15 mills from the battery, the switched power is run off the ignition switch, and far as I know is the 5 volt TTL supply, it may run something else also, .....and the thing has been on line for 18 years, now I fail to see any logic to any other automotive computer ever having all these 'boot' issues, they don't have any drives in them no CDs no hard drives, so IMO you are still over engineering the thing.....


:eek::crylol:
 
Does your ecm load software? No it doesn't

He needs clean shut downs so his OS won't screw up.

Your injectors should be ign switched by ecm power conn.

Only ram power is constant. Yours is on all the time, incl quad drivers. Your cel is off because ecm grounds the lamp to turn it on, 12v gauge power is ign switched also

Sent from my GT-I9000 using Tapatalk
 
Twin_Turbo;107665]Does your ecm load software? No it does't

He needs clean shut downs so his OS won't screw up.


I don't under stand that one....it's a pre programmed computer with a burnt in ROM, no OS involved, way I understand it anyway.....


Your injectors should be ign switched by ecm power conn.



I know that MY injectors are always hot, through a single 7.5 amp fuse....if the computer is not getting signals from dizzy or anyone else to fire the transistors/scrs/whatever the devices are an open circuit, and the injectors set there with a open circuit on the control end.....I Know GM did it was two fuses, one per bank, but being a crude old fashioned batch fire system, I failed to see the reason for the use of two fuses, and mine runs fine Thanks to a good CAM, just for shits and giggles.....





Only ram power is constant. Yours is on all the time, incl quad drivers. Your cel is off because ecm grounds the lamp to turn it on, 12v gauge power is ign switched also



All I know is that I don't have any battery drain....using computer #1227730.....


:clobbered:
 
Ok, there might be a little bit of misunderstanding here, probably me not being clear enough, so let me recap the thing.

I want to install a computer in my car, a PC in a small box to handle all the fancy stuff (GPS, mp3, camera vision). It runs WinXP from a solid state drive, so fast (15s) boot up and shut down.
So I'm installing a device between the computer and the 12v battery.
When everything is off, only the microcontroller in the device is powered, and if correctly put in sleep mode, the power comsuption can be measured in µA.
The microcontroller code is burned in eeprom, so no boot time for the device when I disconnect/reconnect the battery.

This device is also sensing the 12v acc. When it goes on, it will switch on the motherboard power supply, sends the boot up signal to the motherboard, waits for the pre-defined boot time, then powers up the amplifier.
When the +12v acc goes down, it wait for a couple of second (in case the car goes back on shortly), then initiate the motherboard shutdown.
Since it's also sensing motherboard 5v, it knows when the computer actually shut down, then closes the motherboard power supply.

On top of that it will make sure the current process (shutting up or down) entirely completes before taking new orders into account.

It will not mess with any onboard electronic, the car is carbed, so there isn't such.
 
But the ecu needs to completely power down and back up to reset the 0% tps setting on those. The sensor is not adjustable. I would rewire ecm power to ign switched

Sent from my GT-I9000 using Tapatalk
 
I'm guessing that you've:
already checked out MP3Car for some ready made products
enjoy the build - Seen that before :)
Have specific requirements that don't make the off-the shelf viable
enjoy the build - :)

Looking good! :drink:

Cheers - Jim

You guess right, some of the design is actually inspired by posts on MP3Car.
Off the shelf stuff could be use, it's more about the fun of rolling my own.
 
Does your ecm load software? No it does't

He needs clean shut downs so his OS won't screw up.

Your injectors should be ign switched by ecm power conn.

Only ram power is constant. Yours is on all the time, incl quad drivers. Your cel is off because ecm grounds the lamp to turn it on, 12v gauge power is ign switched also

Sent from my GT-I9000 using Tapatalk

But the ecu needs to completely power down and back up to reset the 0% tps setting on thosr. The sensor is not adjustable. I would rewire ecm power to ign switched

Sent from my GT-I9000 using Tapatalk


Sorry Mark, I've read your two post a dozen of time and I'm still struggling to see what your referring to.
Since you're typing from a phone I understand you want to keep your answers short, but could you formulate you thoughts in another way?
 
What's wong with my posts? Check the efi acronyms list

Sent from my GT-I9000 using Tapatalk
 
But I was replying to Gene, not you...he has EFI

Sent from my GT-I9000 using Tapatalk
 
Ok, shutdown controller done :



shutdowncontroller_zps20e49fdc.jpg

shutdowncontroller2_zpsd17e7697.jpg

Made a first prototype, which was a interresing failure.
The one pictured is the second working one.

Stuff learned/mistakes:

-Force applied to connector can break the circuit. Fix : epoxy the connector to the board.
-2n2222 transistor just blow when asked to drive a 12v car relay, I need beefier to220 transistor. I picked two from my recycle box with hfe around 1000.
-Instead of cleaning my copper plate with very fine sand paper or scotch pad, I opted for household metal shining compound. I get a much smoother copper surface, get much less defects.
-Instead of the glossy magazine paper ghetto hack, I bought toner transfert paper. It was cheaper to get them shipped from China than to buy a magazine in the hope of finding white pages. Require of very delicate handling, but the resulting transfert is much cleaner.
-Instead of using tin and solder iron, I used a product called liquid tin to tin my board.
 
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