double pulse bypass (seeking electrical component expert)

[supermanotorious]

Hey guys, I would like to know how to build this module. Amazon and the like sell it for $15-$20 but I bet I could walk in to Fry's Electronic later today and buy the components I need for less than $5 if I just knew what to get.

When the module senses a 12V+ input, it outputs 12V- then nothing, then 12V- again but steady now.

Any ideas?

https://www.youtube.com/watch?v=Lb0UJQ8W3Os

 

[rmm727]

What is the purpose of it?

 

[Badot]

Do you mean -12v or ground?

Assuming you mean ground -- in my very limited experience with electronics (so this may not be the most efficient way):

I'd run an lm339 and a 7486 with a slow cap charge for timing.
As an example, comparator 1 high cap low 8v, comparator 2 high cap low 9v, both outputs to XOR 1. Then comparator 3 high cap low 10v, the output of that and XOR 1 going to XOR 2.

That gives you a rough signal form at least. Not sure what would be required beyond that since nothing is specified.

 

[supermanotorious]

I do mean ground rather than -12v this is to simulate a parking brake being applied, released, then applied again to bypass a head unit restriction

 

[Ready4Dis]

Look into a 555 timer. You will only need a 555 timer IC, a couple resistors and capacitors and done.