Shorter horn chirp?

Hi guys,
Great site, lots of information and a lot of people willing to help.
My question should be simple to find here or somewhere on the inter-web, but I haven't been able to.
I followed the dia. on the relay pages to make the horn chirp shorter and used the 1uf cap. but it still seems a little long to me.
So im trying to find out what which way to go with the caps. to get the chirp shorter. Is it bigger numbers or smaller? I tried a 470 and it didn't seem a lot shorter.
I used a SMD relay, would that make any difference?

Thank you for your time,

John A

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John B.

Are you meaning a SSR (Solid State Relay)?

It will take a resistor in series and the capacitor across the coil of the relay. Without the resistor you are just extending the pulse. If you are using a smd relay chances are 470 mic is huge.

Thank you for the reply,
Yes it looks large. I think I have it as the dia. shows. https://www.the12volt.com/relays/relaydiagram20.html

       

I think I need to go down in size , like a 330 or 220 is that right?

Thanx for the help,
John A

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John B.

The resistor needs to be in series not parallel.

The voltage going through the resistor will slow down the charging of the capacitor. The relay will not energize until the voltage gets high enough.

Leave the capacitor as it is and put the resistor between the alarm and the relay.

Im not understanding? this is what I'm trying to do.



So you mean put the resistor were the drawing shows "switched 12 volt" because that is between the alarm and the relay.

Thanx for the help,
John A

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John B.

Is this an alarm that you are trying to shorten the arm and disarm chirps? If so, the above diagram will only chirp when the alarm is triggered.

My bad, I should have explained what I was working on.
Just got my son his first truck and it had an aftermarket keyless entry in it. The horn goes off on lock for about !.5 seconds, way to long for me or the neighbors. It doesn't have a manufacture or part number on the module so can't check with the maker to see if it is programmable, but the remote does have "ICD"
on it. Does any one know this company, I don't find anything searching ICD? So that's what we are trying to do , shorten the horn chirp, it does seem shorter but not enough.

Thanx again,
John A

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John B.

Post a picture of the remote. On the back of it is there an FCC ID number? Have you tried pressing and holding the lock button for a second or so?

No FCC Number and no luck holding a button down either.
Im going to use a smaller number cap. and wire the relay like the pictured diagram.
I'll post a pic. when I have it made and u can let me know what you think.

Thanx,
JohnA





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John B.

The FCC ID may be inside the case.

Leave the resistor in parallel with the capacitor to discharge the capacitor before the next chirp.

I can't tell from the picture - but do you have both the capacitor and resistor in parallel across the relay coil (instead of in series per the diagram)?

Remove the wire that connects to the vehicle horn wiring. Use a relay if needed to make that wire flash the parking lights.

Thanx for the reply's,
I think I have it just as the diagram shows.
Here is a pic. of my next try, I decided to use a little more dependable relay.



So the attached black is to ground and the rest will wire per. diagram.
Any thoughts, warnings before the fire flys.
I am also trying a 220uf 16v cap. I am looking for around 0.25 or lower.
Thanx again for all the help,
John A.

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John B.

Usually the output from an alarm or remote start that honks the horn is negative going so it would seem that what you really want to configure is this.

Hi, and thanx for the reply,
This is a used "97" F-150 that I just bought for my son.
It came with this key less entry already installed in it. It was working but the horn chirp at lock was like 2 seconds.
I know it does not seem that long, unless you're the one in bed or standing by the truck when it goes off!
Then it seems like a looong honk. So I installed the relay with the 220uf cap. (the one pictured in this post) last night.
Worked great, gave about a .15 second chirp, but while installing it I found out that P.O. or installer wired the horn chirp on there own by tying into the only wire that's active when lock command is given at the remote, that's a 2 second positive output. We then tried the horn button and poped the horn fuse. Then we tried the locks from the switch in the truck and found they also give a .15 sec. chirp.
So my next question is where do I install diodes to prevent the chirp when the switches in the truck are activated and prevent the blown fuse when the horn is used. Or can it even be done?
Sorry about the long post, but I thought some background would help.

Your input is greatly appreciated.

John A
edit: and yes eguru that should have been done in the first place, if so would it have prevented the blown fuse and chirp at switches?

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John B.

If you modify the circuit to trigger from the positive going unlock output to create a momentary negative going pulse for the horn, that should fix all the issues.

Thanx, I will give that a try and post back my results.

John A

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John B.

To fallow up on the outcome, The constant to momentary negative worked great.
Can use horn without blowing fuse and using a 220uf gave me a nice short chirp BUT,
horn still chirps when operating lock and unlock from the switches inside truck.
I think this can be solved with diodes but i'm not sure where to locate them.
Up at the switches, down at the unit, at the horn connection?
I could use a little guidance here.

Thanx you for your time,
John A.

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John B.

You will need to add a blocking diode to your door unlock circuit.