Automotive Power Window Control

[sodamninsane]

First. I don't know where to start with this project so excuse the n00bness.

A little history: For those of you who have ridden in a BMW recently, they do a neat little trick with there door windows. Every time the door opens, the window lowers a little bit, when the door shuts again, the window raises back up to the shut position.

I would like to rig up something like this, hopefully using just straight hardware components (no software / logic) for my car. Reason being, it's a convertible and the windows catch on the top when they are all the way up and I open / close the door.

Of note: sure, I can mess around with adjusting the top for weeks, but there is nothing really wrong with the top. or the seals. And this is just so much cooler.

ANYWAY.

How would I: Build a circuit such that when the door opens (door switch goes high (+12V)) the window motor activates for say, .5 seconds in the down position (output 1) and then when the door closes (switch to 0V) the window motor activates in the up position (output 2) for 0.5s or 1s even.

In short: +12V outputs that can be activated for a variable length of time from either a high signal or low signal (12v signal).

Any ideas?

Thanks in advance,
Andy

 

[3v0]

Hardware alone will not do the job. You are going to need electronics parts, at least a timer of some sort.

3v0

 

[sodamninsane]

as in software programmed timer? Thats what i was kind of trying to stay away from, solely from a cost perspective though.

Anyone know of a reasonably cheap programmable chip / board combo that will take a 12v power source & output 12v control logic or know of a 5v logic controlled relay that can handle a 12v side?

 

[Externet]

A 556 chip contains two timers, could do the job with the aid of a couple of relays and probably one inverter transistor.

When the courtesy dome light comes on (or the door lock plungers if you prefer), (a 12V rising? pulse), one timer activates a relay in parallel to the existing manual 'down' switch for half a second.
When the courtesy light shuts off (a going low? pulse) the other timer activates a relay in parallel to the upward manual switch for half a second.

Industrial time delay relays are more expensive, but can be implemented too, have the adjustable timing, contact and selection of pulse polarity all in one.

 

[sodamninsane]

A 556 chip contains two timers, could do the job with the aid of a couple of relays and probably one inverter transistor.

When the courtesy dome light comes on (or the door lock plungers if you prefer), (a 12V rising? pulse), one timer activates a relay in parallel to the existing manual 'down' switch for half a second.
When the courtesy light shuts off (a going low? pulse) the other timer activates a relay in parallel to the upward manual switch for half a second.

Industrial time delay relays are more expensive, but can be implemented too, have the adjustable timing, contact and selection of pulse polarity all in one.

If i understand 556 timers correctly aren't they adjustable via the resistance on the output side?

In short you've described the circuit I was thinking of, I'll do some research on 556 timing circuits since I don't really understand how to implement the chip.

 

[resony]

i am Mr Resony,foot it

 

[3v0]

as in software programmed timer? Thats what i was kind of trying to stay away from, solely from a cost perspective though.

Anyone know of a reasonably cheap programmable chip / board combo that will take a 12v power source & output 12v control logic or know of a 5v logic controlled relay that can handle a 12v side?

I was not suggesting any solution other then to say you were going to need electronics.

To provide parts help we need to know where you live.
You should be able to buy the relays from either a main line supplier or a surplus place.

If you use 555's or a microcontroller you can use a transistor to boot the current to drive a relay with a 5V coil. You are looking for a relay with a 5V coil and contracts rated at 12V DC and whatever current the windows use. With your plan you will be driving the window motors past the end point so the motors will be stalled, that will mean more current.

If you know microcontroller programming you could use one. You could possibly do the entire setup for $5 plus the cost of the relays. You need a programmer and there are inexpensive options here too.

3v0

 

[sodamninsane]

Thanks 3v0. I live in troy, MI. I'll do some digging and try to come up with a reasonable circuit design.

Thanks

 

[3v0]

For surplus relays look at **broken link removed**.