AIR HORN will not work...........in my letterbox
 

Dear brains trust............I have a car air horn, that is not being used it's its conventional way of being in a car, but in my letter box. It is solely to be used to blow, when anybody but the postman goes near my letterbox. I have run the wires from my lounge room , through the front wall, under my pea gravel front yard and up into my letterbox. Now, When I hook it up directly to my spare battery, it will work as it should. But I have gone through JAYCAR and they suggested a simple transformer ( 240V / 12 v ), that i could attach to my wires, and nothing happened. I returned to the shop, then they suggested this.........12VDC 12.5 Switchmode Power Supply - Mains to Cigarette Lighter Socket https://www.jaycar.com.au/12vdc-12-5...ocket/p/MP3573

After wiring it in, I get a small /short 'toot' noise, the machine turns off...turns itself back on, gives another small 'toot' and turns off ( and repeat ). The wire I have run is 10 meters in length and in a 3amp gauge. Thinking, my horn was buggered again........i attached the spare car battery again..........and the horn works properly. What am I missing to make my horn blow. ? Agreeably, this is a very unconventional way to wire up a air horn.......but I get sick and tired of junk mail, and all the other **** that gets fed to my letterbox. I have a 'no junk mail' sign on my letterbox, and has been there for years..........any idea's? I have a security camera over my front yard, that show's my letterbox on my screens, hence when I know when someone in near my letterbox. I have a wi-fi power plug, that I can turn the power off/on via an app from my phone.

Re: AIR HORN will not work...........in my letterbox
 

Your PSU appears under-spec.

Re: AIR HORN will not work...........in my letterbox
 

I used this in the cigarette lighter, I cut the ends off and plugged the cords into the wire fed to my letterbox.....https://www.jaycar.com.au/high-curre...554cddfaaf51de

Re: AIR HORN will not work...........in my letterbox
 

Exactly........but they sell this 'power supply' as it's possible to run camping fridges. I've gone through the catalogue and have found this adapter. Surely this should push the power....https://www.jaycar.com.au/24v-dc-1-2...plugs/p/MP3494 or even this..........https://www.jaycar.com.au/24vdc-2-5a...plugs/p/MP3562

Re: AIR HORN will not work...........in my letterbox
 

The air home compressor uses a bit of power and requires a decent power supply to make it work. Any specs on the air horn? What size fuse does it come with?

Re: AIR HORN will not work...........in my letterbox
 

Most seem to come with a 30A relay and I set them with “25A” wire as Jaycar call it. 41/0,3mm spec.
20A blade fuse, with inline fuse holder.
As the PSU will power a camping fridge, what about leaving the postie a chilled beverage in exchange for him managing the junk mail?

Edit: Rough calculations suggest 2 gauge wire for that distance, but realistically 4 will probably. work.

Re: AIR HORN will not work...........in my letterbox
 

This one........https://www.walmart.com/ip/12V-Dual-...rain/507631186

Re: AIR HORN will not work...........in my letterbox
 

Well, the one thing that definitely will make the horn work is my spare battery, which is a yellow top optima. I've had it 2 years in my garage, and still holds good charge. I had the idea ( originally ) of setting it up as the main power supply for the horn, and using the house power through and adaptor as the trigger for the relay. But the idea of having a battery sitting in my front lounge room is a bit unorthodox ( though could probably find a place to hide it ). And it's not like I'd be blowing the horn on a daily basis ( though I'd probably catch 1 person trying every week at least sticking something in my letterbox) the battery would be just fine too. But since trying to just set it up to be powered by house power........it's been problem after problem.

Re: AIR HORN will not work...........in my letterbox
 

I can see a bad outcome from this airhorn of yours, best to give up on this project before you give someone a heat attack or worse still someone giving you a hiding.

Re: AIR HORN will not work...........in my letterbox
 

Most cheapie air horns are 30 amp, so your 3 amp wire will be no good especially over that distance, most of the 12V power supplies that Jaycar sell dont have enough amps to power anything more than 10 amps, most of the people that work for Jaycar would not have a clue about electronics so its not worth asking them unless you jag a actual electronic enthusiast that works for them (few and far between).

You would need a power supply 30 amps or more, this one would do the job but you would need to upgrade the wire feeding the horn as the initial start up of the horn would pull the full 30 amps, https://www.jaycar.com.au/13-8v-40a-...upply/p/MP3089

I find Australia post sticking most of the junk mail I get in my letter box.

Re: AIR HORN will not work...........in my letterbox
 

This....


Sounds like a surefire way to have something smashed or thrown through your front windows....

Re: AIR HORN will not work...........in my letterbox
 

Looks good prktkljokr, We'll give this a shot.

Re: AIR HORN will not work...........in my letterbox
 

LOL....They can throw all they want, brick walls and roller shutters can take a few hits..........

Re: AIR HORN will not work...........in my letterbox
 

Depending on the frequency of your unwanted visitors, the neighbours may be objectionable to the method employed here. (just saying)

Re: AIR HORN will not work...........in my letterbox
 

Middle aged woman and her teenage kid do the junk mail rounds in my area. Was out front one day when they were delivering, asked them to only leave the Liquorland catalogue and keep the rest for my house. That's what they now do - figure if I'd asked them to leave nothing they'd probably do that too.

Have you tried having a civil chat with them?

Re: AIR HORN will not work...........in my letterbox
 

Around my area, kids would bang on the letterbox out of hours, just to set off the horn.

With almost $400 in 20m of 4GA wire and a $220 PSU to fire a $30 horn I think the project is resource-heavy with respect to its possible benefits.

Re: AIR HORN will not work...........in my letterbox
 

Have you tried having a civil chat with them?

Yes, we have. While digging the trench to my letterbox ( over 3 weeks ago ), I had 3 different people attend my letterbox and kindly asked them to read the 'no junk mail' sign on my letterbox, and since then......I have had not received any junkmail to speak of. So, honestly, the problem may have already been resolved. Though, .......that dosent mean there's no chance of it happening again. In the last 6 months............if the postman dosent push my mail into the letterbox, and it hangs out the front of the letterbox, I've had 2 people approach my letterbox to pull this mail outwards, and I have come out running and they were quick to disappear. My neighbourhood isnt a bad neighbourhood rally..but all my neighbours have all complained of having mail stolen. Also, with the horn, I ran wires for 3 other harness's for 3 camera's. One for in the letterbox, with motion sensor.......and one for each 30 foot tree on my front fenceline - looking directly at the letterbox to capture any thieves. So as of now, I can get a sensor trigger on my phone for when mail has arrived. Is this set- up over the top.......absolutely 100%. I've already had 2 neighbours request i do the same for them...... and the horn isnt directly there to scare the undesirable person away. It's to alert the neigbours of a possible thief in the area if blown. We all are not home at the same time......but we help each other when can.........apart from my neighbour 3 doors up whom was taken away by the police 3 days ago.

Re: AIR HORN will not work...........in my letterbox
 

Well that's the mail theft taken care of :lol

Re: AIR HORN will not work...........in my letterbox
 

LOL.....it wasnt him. He was friendly upto 4 months ago ( I've known him for years ) until he started doing meth and silly things with it.

Re: AIR HORN will not work...........in my letterbox
 

I think you need a hobby.

Ever thought to just get the junk mail and put it into the recycle bin on your way past?

It really does not seem like an issue.

Re: AIR HORN will not work...........in my letterbox
 

Place battery in a pit in the ground next to letterbox and operate via a relay.

Re: AIR HORN will not work...........in my letterbox
 

Have you thought about changing your mail delivery such that you get everything via email?

Would be much cheaper and faaaar less stressful than what your current situation sounds.

Another benefit is that you can do away with your letterbox entirely, meaning that the junk mail deliverers will simply just skip delivering anything to your place.

No theft. No unwanted junk mail. No need for wires, cameras or air horns. Problem solved.

Re: AIR HORN will not work...........in my letterbox
 

If you don't think that yours is a bad neighbourhood I'd hate to see your idea of a bad one :yelrotflm

Re: AIR HORN will not work...........in my letterbox
 

One of my neighbours in the street took away his letterbox then had all the catalogues pushed in bushes or strewn on the lawn, letterbox was quickly resurrected for junk mail :yelrotflm

Junk mail and hawkers are scourge of society.

Re: AIR HORN will not work...........in my letterbox
 

Have you considered one of those proximity frogs, which sit on the ground, and 'croak' 'croak' 'croak' when someone approaches.

https://www.amazon.com/Bits-Pieces-R...dp/B00VRW4RCC/

think of the hours of joy you will get as people wtf

Re: AIR HORN will not work...........in my letterbox
 

Yep or PO box, easy.

Re: AIR HORN will not work...........in my letterbox
 

North of the river suburb 'BALGA' is one of the worst crime suburbs, with Armadale ( south of the river ) worst in the south with lots of criminal activities. Anybody in perth have heard of these suburbs as crime capitals............with rockingham coming in a hot 3rd place. And I live no-where near these area's. I live opposite 3 football fields that are always filled with all different nationalities - people playing soccer , volley ball and plenty of yoga/Pilates ( which my elderly neighbour likes to watch in his chair )classes in the morning. It only takes a few ****WITS to ruin the area.......but since starting this thread, I've had no junk mail even though the horn is now wired up and ready to go. Here's the vid to show....clicky clicky...https://www.youtube.com/shorts/KutpByEK_wE This whole operation was to scare the people delivering junk mail and other small notices. I once had a pamphlet delivered , stating they cut lawns at low prices................I dont have any grass on my property to speak of. I only had probably 2 pieces of mail go missing in the 10 years I've been there.............but my neighbours complain all the time. And I've thought of having all bills changed to emails, but i like my paper bills. I mess up my emails already enough, without worrying about bills coming through.