help with window closing project for car

In the car I have the window switches for passenger and driver on my door. If you give the drivers switch a little flick the window closes/opens on its own, but the passenger one required you to hold it down.

I want to make it so that i can monitor the switch and if it's a flick to hold the output closed for x seconds. I'll time it when circuit is sorted. If the switch is pressed again while its in the "auto" mode, it should open the switch and stop the window.

I can either use a PIC microcontroller, easiest for me, , or an electrical circuit.

Help please.....

Find where the contact is connected when you push it, take that 12-14 volts down to less than 5, voltage divider or small 7805. Use an input pin on a microncontroller. You see a high on that pin, start a counter. If the counter is less than what you want (flick), use an output pin on the uC to a transistor to drive a relay for as long as you like (via a delay routine).

you should also use some kind of smart motor driver that will detect when the the window is closed and stop sourcing the motor. the driver L298 can do that.

Why i say this is because i imagine the worst condition, if your window is half-open, and you give a flick to close it, the motor will work to life the window the remaining distance, and then, will be powered without turning for the other half of the timing, which could burn the motor.

Unless your car allready has its cut-off circuits...i guess it does, in that case, ignore what i've said!

ikalogic said:

you should also use some kind of smart motor driver that will detect when the the window is closed and stop sourcing the motor. the driver L298 can do that.

Why i say this is because i imagine the worst condition, if your window is half-open, and you give a flick to close it, the motor will work to life the window the remaining distance, and then, will be powered without turning for the other half of the timing, which could burn the motor.

Unless your car allready has its cut-off circuits...i guess it does, in that case, ignore what i've said!

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My car should do, as holding down the window switch too long does it no harm. plus i really want the circuit to be simple.

I would strongly urge you to NOT create a circuit that automatically raises the windows (and i doubt the driver's side does this either). This is an accident wait to happen. Scenario - you push the auto-close button and some one sticks their hand in at the same time - smush. In some countries, the lawyers would eat you for breakfast. In others, the guy or their relatives would teach you a lesson.

Your existing circuit should have limit switches so all you need to do is figure out how intercept the switch (should be 3 position - on1-off-on2) and then use logic fake the signals. You might get away with just timing the down signal if the limit switchs stop the window motor when down. Otherwise, you will need to tap into the limit switches and turn off the signal.

You might be able to use 4xxx series logic which runs on 12V to avoid creating a 5V powersupply but verify what voltage the switches are running at. I would also guess (you need to verify) that the switches are "pulled high" and carry no appreciable current. You should probably protect your circuit from battery reversal (it happens) and over voltage (happens, too) and spikes. Make sure you use the widest temperature range parts possible as a car can get very hot or very cold.

And, take lots of pictures before you make any modifications. If you want to rip your mods out later, you will appreciate it.

I think mine go down with a click, but not up. Philba is right. That would be a bad thing with a hand or any part in there.

Maybe current sense and override it. But this sound like a lot to just have the window automatically roll up.

Now that I think about it, the alarm in my spare (78 vette I am restoring) does roll the windows down and I think up as well.. I will have to check, but it is a BAD idea. I agree..

i think you have plenty of free sapace in the car's door. you can put a performant circuit in there that stops if an object interect the door. but if you want it simple, then, follow those guys advices, i didn't think about it at the first time, but it could be really dangerous.

I checked. Down, but not up.. So if the big auto guys are afraid, you should be too.

The drivers window does go up and down on auto if you flick the switch.

As for getting bits stuck in their, I tested my particular car and the drivers side has a safety device that stops the window when i held it from moving up, yet the passenger one didnt.

Strange, but it means i have to put a safety device in to the circuit if I am to mass produce this, but for the time being in my car I will risk it.

Power window controllers are common in my business. I install/sell car alarms. We install these all the time to roll windows up or down. They all have current limit cut offs so they stop when the window is all the way up or down or if something is blocking them. The controllers are only about $20 and they will control 2 windows in one direction or they have 4 windows versions that will roll up or down all 4 windows at once or take 2 windows up and down.

Here is a link to one from Parts Express
**broken link removed**

by the way, I just bought a new car and the widows go up automatically. I tried preventing it from going up and it automatically reversed. my 6 yo van doesn't do that, just auto down.

So what is the current level for my window motor (here in the states) that I (or it) should cut it off at? Is there a standard?

Also, what do I need to tell my insurance company just in case?

I will call the ozonewatersystems.com in the morning. For a window motor device not a water device.

mramos1 said:

.....I will call the ozonewatersystems.com in the morning. For a window motor device not a water device.

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Ozone Water is the company I now work for at my day job and won't have any idea what you are talking about if you ask for a window controller . Quality Sound is my mobile electronics company which I now do part time on the side. Sold my two stores a couple years ago. You can email me shanec@c4caraudio.com or call me at 602-570-1307 (cell) if you want help finding the window controller. The link above to parts express is a pretty good price but I can get one for you if you want. Prob. about the same price as Parts Express.