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DIY Total Closure for a car

Discussion in 'Electronic Basics' started by Simon Burrows, Aug 11, 2003.

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  1. Hi all,

    First of all, apologies for the cross-post! It's gone to some car ngs aswell
    as electronics ones for both sides of the story :)

    I'm just having a little play around with the idea of adding a circuit to my
    car's stock alarm that will create a total closure system (i.e if
    windows/sunroof are open they will be closed automatically).

    In theory, I guess this should be pretty simple... all the windows/sunroof
    etc are electric so I just need a circuit that switches to either positive
    or negative (depending on which the window switch needs) when the doors
    lock.

    Unfortunately my electronics has got a bit rusty over the last few years
    (since I stopped studying it when I was 15!) so I was wondering if anyone
    could help me out with the sort of thing I should be looking for?

    From memory, this is the sort of thing a 555 timer could control, isn't it?
    I've found a prebuilt PCB based around the 555 timer (the K2579 Universal
    Timer) which has a variable resistor to control the length of the delay.
    Would this be suitable for my application?

    Thanks for any help,
    Simon Burrows
     
  2. Scott M

    Scott M Guest

    Only as long as the windows/sunroof have end-of-travel sensors to cut
    motor power. A lot of makers don't bother simply letting the motor stall
    which, if you're doing this for 15s each time you lock the car, they'll
    soon burn out.

    As to choice of unit - a simple transistor/resistor/capacitor/relay
    circuit would do. Last time I used a 555 in the car it literally[1] blew
    itself into pieces the first time the engine was fired up. It was a
    super low power version though - I've had success before with the
    "normal" sorts.

    --
    Scott

    Where are we going and why am I in this handbasket?

    [1] And I used the word in its precise sense
     
  3. Cheers, so theoretically it should work. I'm fairly sure my windows have end
    of travel sensors... but I'll check that they do. The driver's window has a
    one-touch up and down switch, so that must have end of travel sensors to
    avoid burning the motor out. The passenger one I'm not so sure about. Same
    with the sunroof, that has a one-touch closure button, so I'd assume that
    has sensors too.

    Thanks a lot for the tips :)
     
  4. Grog

    Grog Guest

    There are commercial units available to do this, sold as add-ons / optional
    extras.
    But if you really want to do it yourself, here's a couple of pointers...

    You won't usually find limit switches, typically the controller senses the
    increase of the motor current when it stalls. This is normally at the end of
    each travel direction but also includes when something gets in the way.
    Children and dogs to name a few.

    The 'one touch' buttons are best described as resetable circuit breakers.
    At the end of travel the current goes up and cuts off the switch.

    One of the smarter controllers I have used was sensing the motor brush
    noise instead of the current. Noisy while the motor turns, quiet when it
    stops. Very tricky I thought at the time, a long time ago..

    This one was also sequenced and could drive up to four devices. By
    sequenced, I mean that it only did one at a time. When one finished closing
    the next one would start, etc... etc...
    Doing it that way makes for a happier battery...

    Small Japanese (car's) windows were often lower power and easy to close
    but a Mercedes or big old Chevy were much more power hungry. The
    current sensing controllers often struggled with these.
    The sequenced controller was also useful for closing a convertible(roof) in
    that the roof must be closed fully before the windows go up.

    Even did a rain sensor for one installation too, closing a sunroof and
    windows if the driver forgot about it.. Save him from a soggy seat.

    Food for thought I hope... ;-)

    Greg the Grog
     
  5. Previously, <MiPZa.28622$>, Grog
    And idiotic 'mates' - the bloke who was supposed to buy my Golf GTI when
    I first got it ended up buying an X reg Golf GTI 1.8T instead (his
    girlfriend made him finance a newer car, instead of running a 'banger').
    So far he's ended up with a few hiccups, but the best must be the mate
    seeing if the windows did that 'stopping thing' when something gets in
    the way.

    They sortof do. The window mechanism broke.
    Then the door trim broke when he tried to fix it.

    Citroens have stall type shutoffs, as do Volvos - later 480s have total
    closure, in fact.

    Richard
     
  6. marko

    marko Guest

    Go buy a mk2 (with curvy bumpers/bonnet bulge/grille) Rover 800 and
    take the window motors (with position sensors); centre locking motors;
    'CCU' unit; keyfob and IR receiver; the whole wiring loom then graft
    that onto chosen car.

    One shot up/down on all windows/roof; current sensing on all windows
    and sunroof; sequenced total closure/lazy locking; 1 minute delay
    after ignition off to let people close the windows; you name it it
    does it. If it still works anyhow; the rbush sensors on the motors die
    and the switchpacks die - replace these and you're fine for 10 years
    until they die again.
     
  7. Very nice idea, but I don't really wanna rip too much of the car apart as
    it's not that old and still worth a fair bit on resale (V reg, new shape
    Celica).

    Anyone had any experience with Microscan alarms? They do a total closure
    add-on module which I bet could be adapted to do the job...?
     
  8. Previously, <no3_a.4286$>, Simon
    Yargh, why are you wanting to bodge a V-reg Celica!

    Don't Clifford do good modular alarm systems, or am I still living in
    1996?

    Richard
     
  9. Jamesy

    Jamesy Guest

    snip
    They do modular systems - "good" is another matter. Apparently they have
    improved recently but the past few years have seen /lots/ os dissatisfied
    Clifford customers.
     
  10. Nom

    Nom Guest

    Agreed !

    Phone your local Car Audio place, and buy a top-spec alarm system. Will cost
    well under a grand, including fitting, and will do everything you want.
     
  11. `-'\_)Morticia

    I am going to put a new alarm on the car in the long term.. this was just a
    short term fix for an annoying problem. Shouldn't really require much
    bodging, literally just adding a circuit into the mix.

    If it starts to look too hard and it's possible that I might mess something
    up, obviously I'll just wait until I can spare the cash for the full new
    alarm system (quite fancy one of the Cliffords with remote engine start
    etc)...
     
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