Putting A Car Horn On Your Bicycle!

I'v found in my biking adventures, drivers are aloof, distracted and just plain blind to us little pieces of metal on the road.
I'v also found giving a little shout before a driver makes a right hand turn with out signaling is a great way to save your life, but i like my voice to not be raspy after running around town. This project started with a little 12 volt scooter horn that i ran off of 9 volts, and i found it just wasn't loud enough.

SO the car horn project was BORN!

enough from me, lets get on with it!

Step 1 Scavanging List

-One Car Horn (louder the better, test it out before buying. try scrap yards. i found mine under a friends house. Some are 12v some are 14v. I have not found a good way to test this other than hooking them up to batteries.)
-Battery Pack (For this demo i'm using 12 volts of AA batteries, i strongly suggest for permanent use to get something rechargeable. You can safely go to 14 volts with these horns and some horns need at least 14 to function. Lead acid batteries are too heavy for most but would work great, I'm getting some discarded laptop batteries in a week.)
-Push Button Switch (get something you can imagine triggering safely and be able to reach your breaks. Be sure the voltage works for what you're doing.)
-Electrical Wire (I'm using 18 gauge to do the hook up, any will do.)
-Plugs and Hookups (to take the battery pack with you when you park, or to recharge it. Every horn is different to hook it up.)
-Hardware (anything to attach the horn to the bike.)

Things you should have:
-A Basic soldering set with solder, an iron and clean working space
-Multimeter, so you can test voltage with out blowing the horn every time
-Time, not a lot of it but a sufficient amount.

Comments

[jerry3]

Hello and thanks for this tutorial !
But please tell me, does the amperage matter ?
I found nor expensive 12V 0,8A batteries.
Will it be good?
Thanks in advance.

[qola]

i don´t think 0,8A is enough i would say at least about 2 amps

[gtoal]

I recently built something very similar (not knowing about this instructable) and here's what I found:

1) 2600Mah lipo taken from an RC helicopter, notionally 11.1V, actually measuring 12.5V, makes a great battery. Compact and light.

2) I originally built the relay and used a fuse as recommended by the horn manufacturer. Not only were they unnecessary, but something about the way the horn pulled current caused the relay to lock open, even though it worked correctly as a momentary-closed switch for other devices. As long as you are not powering anything else from your battery, are not running earth through the bike frame, and use a suitable gauge of wire, this shortcut seems to work OK.

3) To be able to user the expensive LiPo battery elsewhere, I didn't cut off the power connectors, but bought an adaptor and cut that off (Mini Female Tamiya to Female Tamilya) to have a wire I could crimp.

I made a switch housing by stripping down my bicycle bell and fitting a car button inside it - some Dremel work required!

Damn it's loud!  Has deterred several potential accidents already :-)

PS If you do use a relay, taping 4 3V CR2032 button cells together to make a low power 12v batter works great with 12V-actuated relays.

[sarahfish]

any suggestions of a switch? I'm going to try this to replace my car horn (we live in the west indies, so mechanics are non existent) I'm conformable with the wiring and mounting of the system, just don't know how to pick out the right switch to go onto the car battery...

any thoughts much appreciated!

[aroff]

I like that can be use for unfriendly traffic in Singapore

[pogoman12345]

Car: BEEP BEEP
You: BEEP BEEP
Car: BEEP BEEP
You: BEEP BEEP BEEP BEEP

[frenzy]

see i win because i have more beeps

[unaffiliatedperson]

i installed one on my beach cruiser. just removed the rear reflector and botled it to the bracket. howerver i have a drill battery. im a bit dissappointed by the tone it makes sounds more like a VW than the "deep tone" it said on the packaging at autozone

[DavidKaine]

Best thing to do would be to use a relay for the horn, and use the switch to trigger the relay. This is how it's actually done in cars. Also, to protect the batteries you might want to wire a capacitor in parallel with the circuit. Otherwise, fantastic idea!

[jimmy dean]

Wouldn't that be a little redundant?

[lycoris3]

how is that redundant? Just curious.

[jimmy dean]

The relay I mean

[DavidKaine]

To a degree, yes. But if you look at it, a car horn can draw a significant amount of current. If you put the relay right next to the horn, you can run (as an example, this depends on the rating of your electronics) 10 gauge wire to the horn from the relay, but only run a thin 18 gauge wire to your handlebars to actuate the relay.

[sarahfish]

Same question to you Dave,
any suggestions of a switch? I'm going to try this to replace my car horn (we live in the west indies, so mechanics are non existent) I'm conformable with the wiring and mounting of the system, just don't know how to pick out the right switch to go onto the car battery...

any thoughts much appreciated!

[DavidKaine]

I would need more information about which part of the system you are replacing and how you are setting it up, as well as what kind of parts you have access to. Feel free to PM me and I'll do my best to help!

[armourkris]

I may have to try this. been wanting a good horn for my bike for a while.

this kind of makes me think of my buddy's alarm clock. i made the mistake of pointing out to him that the local princess auto was selling surplus soviet air raid sirens for $10. so he got one and wired the damn thing into his alarm clock. He only used it once and woke up half the block. it would have been more awesome if he wasn't my upstairs neighbor.

[lycoris3]

can you have him do an instructable? That sounds awesome since I am a slow riser in the morning.

[XOIIO]

Sweet!

[thepaul1993]

You dont need a car horn. You need a fog horn from a ocean liner.

[Xellers]

http://cgi.ebay.com/Old-RMS-Queen-Mary-Cunard-Ocean-Liner-Ship-Fog-Horn-/310231939692

[Raydoom]

tried this many years ago had loads of fun beeping at pedestrians . also i would recommend using a 12v sealed lead acid battery got mine for around $20

[cozmicyellow]

Use a standard alarm panel battery,  Im a security technician,  go into any place that installs or sells alarm goods, and ask for a 12v alarm battery,  and a PSU unit to recharge it.  Probably be about $50 for both thou,  But the battery will last 2 years+ and the PSU forever

[mrcope5]

if you check your local motorcycle shop you can find brand new 12v horns for under $8.

[cjyoyo17]

thanks, will do, but where are they?

[mrcope5]

any motorcycle dealer.  i've bought them from kawasaki dealers, honda dealers, and ducati.

[stevie1]

car horns are pathetic... use a FREIGHT TRAIN horn!!!!! and conceal it in saddle bags.. you could scare soooo many people.

[Lokisgodhi]

Yeah,  put this on a bike. Obviously this maroon has no idea just how much these things weigh.   

[livesteamfan]

 Train horns aren't exactly a good idea. For one, they require air pressure to work and it would be rather difficult to carry around a compressor with tank, not to mention the amount of power it would take to operate it. Second, you would go deaf in a short period of time. I've been in an Alco Rs-3 and it is LOUD!!!

[sarikoshi]

I suggest getting some lower priced batteries.
like these: www.hobbycity.com/hobbyking/store/uh_viewItem.asp
buy ten of these and tape it together or make some sort of mount for it.
spares you a lot of money

[vader0ne]

Just wanted to let you know the hobby city link above is bad.

[sarikoshi]

 thanks for letting me know
new link:
www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=10456&Product_Name=Turnigy_AA_LD_2200mah_Low_Self_Discharge_(ready_to_use)

[computer_freak_8]

I've always wanted to do this, but never wanted to have to worry about the batteries/battery. I ended up with an Air Zound (or was it an Air Zound 2?) bicycle horn. I loved that thing, but I could only get one or two good blasts on it before it needed refilled. (It's an air horn that refills via a standard valve stem, like the ones on the tires of a bike/care/whatever.)

It looks a bit different (the coloring), but it looks like this is it here:
http://www.deltacycle.com/Airzound-Bike-Horn

It's about as loud as a semi's airhorn... not as loud as an ambulance or firetruck, though. (At least, judging by the semis, ambulances and firetrucks around here.)

[HaveFunWithIt]

 Couple of random thoughts:
For air horn use a tank with Liquid gas of some kind. More honks for a fill up.  CO2 might work for short honks but might also temporarily freeze the horn if it has moving parts.
Also If you had a bike with a large frame tube it might be possible to tap that tube and fill it with air pressure or liquid gas and use it for a mini tank.  Just a thought you might get a couple of honks out of a small horn.  You could use the plastic horn off a handheld horn in a can for lack of a better name. you know the ones you can buy for boating or other uses. Also I had a tiny little personal safety device I found at a yard sale it was a VERY high pitched scream of a whistle.
Ad an old Dynamo from an old bike light to recharge the battery(ies).  Not sure what electrical components might be needed for this to charge correctly.

[BikeTac]

You want a good loud and inexpensive bicycle horn? Check out www.biketac.com

[Skaterbear]

I tried 8 size D batteries and all I got was a click. Also tried a buncha 9-V batteries series, parallel, pairs, etc... same thing. What worked was two of those NiteRider 6-V Trail-Rat rechargeables in series. Expensive, but so far so good. Only did this yesterday, so I have no clue how quick this eats the batteries. My wife wants one on her bike, now, too. Lots more cash out, but what price safety, huh? Hey, do you have the brand name of the horn you used that worked with 8 of those little batteries? Or even what kinda car it came from? I have seen other bikes that do this, but I think they are running some huge heavy lead acid battery. I load up my bike a lot for commuting and travel, but that kind of battery would be too bulky even for my style. Thank ya!

[Casper250]

We're developing a horn kit that includes two small disc-style horns that blast 136dB and are powered by a rechargeable 12v battery. Together, they weigh less than two pounds. One is a high tone and one is a low tone. The kit will come with everything pre-wired and assembled. All you have to do is attach the clamps to the cycle frame. The battery is sealed and spill-proof and the case can be mounted in any position. It is rated at 1.3 Amp Hours which means that you can do a lot of honking before recharging the battery. The whole kit will be available for around $100. An optional trickle charger will be also available. We have several other horns available, including air horns with a built-in mini-compressor, if you prefer. The wiring required for these is a little more complex, but still very workable on a bicycle.

[frenzy]

hey, so the horn i used came from a wheelchair which i think it's more used to running on 12v. I found another car horn and it wouldn't make noise unless i got it to 14v! Batteries have been a huge problem for the sustainability of this project i'm eventually going to get some heavy duty NiMH from ebay but i have to make sure i get one with enough volts. An easy fix is using a lead acid but they are so heavy! Any ideas will be apreciated, i hope to do a part 2 this summer.

[Bran]

How do you charge li-on laptop batteries without the laptop?

[lycoris3]

Could keep the parts of a computer laptop that let you recharge with and hook it up to the cycling system so you recharge it yourself while ridding. I personally do not know how to do that, but it sounds like it can be done.

[omnibot]

Good idea and build but builders beware of AC-horns.