HELP - Need to make a timer - 555 Newbie ???

[bilabonic]

Hi All

Looking to make a timer which allows me to operate my convertible roof up/down.

At the moment i need to keep my finger 'pressed' on the button to operate up or down.

After a while (about 8 secs) it hits a limit and the motor stops, it makes no difference if finger is held on the button.

This is the same for both directions.

How can i make a timer circuit to give me a 8 secs on pulse when pressed once.

I will also need the option to stop the hood midway for access of engine/maintenance.

Can this be done ??

Cheers

 

[Hero999]

Yes, it can be done but it depends on the motor controller inside the car works, it might be easier to redesign it than hack it.

 

[MrDEB]

the 8 sec is easy

just insert a relay between the pushbutton to battery supply
perhaps a second button to stop the top midway?
**broken link removed**

 

[bilabonic]

I was thinking of having a relay/s on the ouput and wire it to this, so it just replaces the switch as such ?

 

[bilabonic]

just insert a relay between the pushbutton to battery supply
perhaps a second button to stop the top midway?
**broken link removed**

Seen that page and am totally lost , so many circuits there would not now which one to go for ?

Anyone advise...

Cheers

 

[bilabonic]

Would two 555 monostable timers be the answer ?

Something like 2 of these circuits ? How can i make the time adjustable or work out a set time ?

 

[Hero999]

As I said above, you don't know how it's wired up.

There could be two switches, one for forward and one for reverse or it could be one DPDT switch which forms an h-bridge in itself.

If it's two switches, then you'll need a 555 for each and three buttons, one for forward, one for reverse and one for stop (reset). You could use the existing rocker switch for the forward and backward and add an extra stop switch.

EDIT:
Please post a picture of the connections on the back of the existing switch.

 

[bilabonic]

The micro switches will not come into it though. I could have the timer run for an hour id f i wanted. The roof takes 8secs to open and 8sec to close. If held longer it causes no harm.

All i want to do is replace the time i hold the switch with a relay controlled by a timer. Set to 10sec/or15secs so i can be sure it fully closes/opens.

 

[bilabonic]

Like this - The 555 Monostable Circuit - More Detail

With timer set to 10secs and the relay output replacing the current switch i hold with my finger.

 

[Hero999]

It might not be that simple.

If you activate the forwards, then the backwards both switches will be activated simultaneously which might damage it.

 

[bilabonic]

Good point, i presume i could wire a contact of one relay in series with the other and vice versa for an interlock.

Is there no to to interlock the 555 timers?

This is out of my depth i think....

 

[Hero999]

There are ways of implementing an interlock.

Post a picture of the connections on the back of the switch.

 

[bilabonic]

Cheers hero mate. Trying to remove the trim. I am hoping to see a common and up/down as it's a self-return toggle switch.

 

[MrDEB]

just find a wiring diagram

what make, model, year of auto?
most can be found on web

 

[agis68]

hmmm....what if u use a double exit relay one direction opens the other closes and 2 equal 555 timers resets......then u can adjust with a pot the time you desire.....but now iam on vacation and i have not any schematic to send u.....next week u will have one if u can wait, but u can find it also on google...

look in **broken link removed**

 

[bilabonic]

what make, model, year of auto?
most can be found on web

Hi

The car is a facelift model 04 Porsche Boxster.


Cheers

 

[bilabonic]

hmmm....what if u use a double exit relay one direction opens the other closes and 2 equal 555 timers resets......then u can adjust with a pot the time you desire.....but now iam on vacation and i have not any schematic to send u.....next week u will have one if u can wait, but u can find it also on google...

look in **broken link removed**

I have looked at that page mate and it's above me, i have came here for help. I am from an electrical background but in heavy industry, i just replace the pcb not repair them....lol

Cheers

 

[agis68]

sorry then for the link...but look here that's good for u
**broken link removed**