Hello Genius..!! I need a Smart Electronic Guru !

[Paporro]

Hello Genius !!

Do you remember the car alarms that blink the car lights one time to ARM and blinks two time to disarm ?

Well I need to built a electronic circuit that detect that blinks ...

I explain ..

It is a circuit that feel two consecutives blinks .. and then close a Relay..

Yes I need to detect that blinks ..

The blinks have 1/2 seconds duration between each one ..


Please Gurus ..... give some ideas ,,,


Thanks in advance ....

 

[blueroomelectronics]

They use a microcontroller. Almost any will do.

 

[Paporro]

I need easiest solution //

more suggestions

 

[Papabravo]

Do you mean to say that you think there is an easier solution? I guess that depends on your definition of easy. How about a state machine in an FPGA. Would that be easier? Maybe a discrete implementation of a state machine, say 5 or 6 MSI chips. Would that be easier? How about some relay ladder logic. Would that be easier?

How about a definition of easy, before we go spending alot of time proposing solutions that don't meet your requirements.

 

[goonsvondoom]

What you'd like to build is not terribly difficult. Depending on what you want the device to do after it detects the light and also as a matter of design the lighting in the environment it will operate in (daytime brightness and different angles of light may present a small challenge, those lights are usually a pretty dim red LED also) there are a few routes you could go. Using a microprocessor, a small breadboard and a few components you should be able to make it work. If you can ask a slightly more specific question I might be able to give you a better answer. Is this going to be used for something important or are you just messing around?

 

[Paporro]

My project is more easy ..

Thanks for the help ...


My project is more easy ..

The device will be directly connected to the car lights circuit .

the car blinks 2 times when the locks open..

I only need to activate a relay with 2 consecutives pulses of blink (12v)


I need to activate a relay in that moment ...


Suggestions ??????

 

[kchriste]

And then what happens? Does the relay stay on forever? What turns it off again?

 

[Paporro]

Don't worry ,,

kchriste

Don't worry about that !

Thanks for help


Any idea about my job ???

 

[blueroomelectronics]

Yes use a microcontroller, that's going to be the easiest solution but you'll have to learn programming and you'll need a programmer.

Or you could contract someone to design it for you.

 

[Ubergeek63]

74HC4017 and a 2Hz osc... what is the hang up lately that everyone thinks every stupid little sequencer needs a micro?

 

[blueroomelectronics]

74HC4017 is a Johnson counter, it can be used for sequencing lights (I'd suggest a CD4017 as it'll handle > 13V). The OP did ask for easiest solution.

 

[kchriste]

Ubergeek63, how is a 4017 and oscillator going to help? If I've read the requirement correctly, the OP wanted to detect a double flash sequence, not generate one. What the OP needs is a negative edge triggered one-shot that activates an AND gate which lets the 2nd pulse through to trip a D type flip-flop.

 

[blueroomelectronics]

You'll also need to do whatever you can to detect false triggering. Again a micro is going to be much easier than a bag of logic ICs.

 

[kchriste]

Yes, a PIC, AVR, etc would make the whole job easier. Using a small 10F or 12F series PIC is the way I would do it. But it wouldn't be the easy way for someone with no microcontroller experience.

 

[Pommie]

I like Ubergeek's suggestion, if the light pulses clocked a 4017 then it would work. The zero output would hold a timer in reset, output 2 would trigger the relay and the (2 second) timer output would reset the 4017. If two pulses arrive within 2 seconds then output 2 would go high and trigger the relay.

Mike.

 

[grim]

how about charging a capacitor via a resistor and diode. if you use the correct values one pulse would charge it to 6v and the second would get it up to about 12, and a 12v relay could pull in

of course it would work when you indicate as well