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12 volt timer switch circuit

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andy007

New Member
Hi
Im building a project kit car at home and need some help.

I need a very simple 12v 0 to 10 second timer. What it needs to do is this.
When the ignition is turned, a +12v will be sent from the ign-switch to the timer, activating the timer for upto 10 secs to illuminate a max 1w bulb on the dashbord then go opencircuit or switch off after the 10 secs. Similar to the way the engine management system or door lights work when you start your car.

It would be great if you could show a diagram with components so enen a idiot like me could follow and install it.

Many thanks in advance

Andy007
 

MikeMl

Well-Known Member
Most Helpful Member

andy007

New Member
12v switch

hi all

thanks for taking the time to help me. will have a look and let you all know

atb

andy007
 

Reloadron

Well-Known Member
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Maplin's website is like watching grass grow. Try DigiKey. You don't mention your location?

Ron
 

dannybhatti

New Member
thanks 4 that never heard of either site let you know once i build it new to all this pcb. building a timer switch to on my glow plugs before i start the car as you put into key position 1. connected a switch with a varible resistor on the temperature sensor if i forget to of the switch the tool light goes on and the car goes into limp mode and takes ages to go back to normall .i dont know whats wrong with the car checked everything cheers from leicester
 
Hi
Im building a project kit car at home and need some help.

I need a very simple 12v 0 to 10 second timer. What it needs to do is this.
When the ignition is turned, a +12v will be sent from the ign-switch to the timer, activating the timer for upto 10 secs to illuminate a max 1w bulb on the dashbord then go opencircuit or switch off after the 10 secs. Similar to the way the engine management system or door lights work when you start your car.

It would be great if you could show a diagram with components so enen a idiot like me could follow and install it.

Many thanks in advance

Andy007
This circuit should do something like what you need.
When you supply 12VK (ignition key) the relay goes on and keeps that condition for 60/90 seconds.
555 time calculator
 
Last edited:

Tartan18

New Member
Hi
Im building a project kit car at home and need some help.

I need a very simple 12v 0 to 10 second timer. What it needs to do is this.
When the ignition is turned, a +12v will be sent from the ign-switch to the timer, activating the timer for upto 10 secs to illuminate a max 1w bulb on the dashbord then go opencircuit or switch off after the 10 secs. Similar to the way the engine management system or door lights work when you start your car.

It would be great if you could show a diagram with components so enen a idiot like me could follow and install it.

Many thanks in advance

Andy007

As Andy stated at the beginning of this thread I am also looking for a circuit design (as simple as possible) for a 12v 10 second (time is not critical) timer. I want my seat belt light to illuminate a 3w bulb on my dashboard. I've looked at the circuits thus far in this thread and I think I can follow the wiring paths but what I would really appreciate is a list of the component parts needed for the circuit design. I can read a schematic but I am not an electronics wiz. Any help would be appreciated.

Jim ...
 

MrDEB

Well-Known Member
delay simulation

Will get a BOM for the circuit I posted.
CAUTION if thinking about this circuit https://docs.google.com/leaf?id=0B7LPpongh6DzYzY0NmM4MWUtZDA2MS00YjlhLWEwYWUtYjcxMzMwOGVmODFj&hl=it
ther relay will cause magic smoke to emit from the 555 as it needs a transistor or ? to prevent blowing the 555.
here is a simulation of the circuit I originally posted with slight changes to the time on.
NOTE I show no output transistor or Mosfet on pin 3 output. Needs to be added.
Boy andrewsblog has one heck of alot of transistors. in that circuit what little I canm see (not very clear the picture, contrast is bad)
Seems it would be easier and cheaper to use a PIC.
 
This circuit should do something like what you need.
Actually I simulated it with Microcap but I didn't build it, so I'm not sure that the circuit works fine. However you shouldn't damage the output if you use a 12V/140ohm coil (85mA). Anyway do not forget the reverse protection diode, even if you connect the coil by a transistor.

The second circuit schematic I posted has been tested for real...

View attachment 62513
 
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Tartan18

New Member

Reloadron

Well-Known Member
Most Helpful Member
An adjustable (1-90 second) timer-controlled 30A relay For temporary circuit connect/disconnect applications
Maybe I am missing it but they don't say much? Would it be a delay on make or delay on break adjustable? It sounds from what I read that what you want would be a one shot where once triggered it would give a high output for a period of time then go low till triggered again. I am not sure the product linked to does that. Maybe another member has some thoughts?

Ron
 
I found more info here.
If I was in your shoes I would buy it.
CAUTION: by installing DIY (not certified) devices on your car, you may get problems with insurance companies.
Note that I built my circuit just for fun.
 

Tartan18

New Member
I found more info here.
If I was in your shoes I would buy it.
CAUTION: by installing DIY (not certified) devices on your car, you may get problems with insurance companies.
Note that I built my circuit just for fun.
This clarifies it for me. Thank you very much. I am not concerned about any insurance issues because my car is a 1975 Fiat 124 and I have already made many after market changes. I am going ahead and buying the Directed Electronics Pulse Timer Relay.
 

Reloadron

Well-Known Member
Most Helpful Member
Yep, for that price buy it. :) Nice link.

Ron
 
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