Introduction: Car Horn - Custom Sound Effects

About: Mechanical Engineering student at the University of North Carolina at Charlotte

I installed custom horn sound effects in my car based on YouTube videos by Mark Rober and I Like To Make Stuff

The basic car horn needs more options for effective communication between drivers in my opinion. Where I'm from the standard car horn has a negative connotation and sounds "angry". This project adds three (or more) sound effects that play at the push of a button.

The sound effects I'm currently using are a courtesy honk, a bicycle horn sound, and a clip from the Cantina Band found on sound effects websites.


Sound effects are stored on a soundboard. A 100W amplifier is used to amplify the sound effects before being played through an outdoor speaker mounted in the engine compartment. The whole system is powered by the 12 car plug and sound effects are activated by push buttons.

Components are interchangeable but here's a list of what I used:

Step 1: Sound Board

I started by familiarizing myself with the Ardafruit soundboard and picked out the sound effects I wanted to use. Adding sound effects was as simple as dragging and dropping the file and changing the name. Note: one benefit of this sound board is you can plug in your laptop and upload new sounds at any time.

To test the board I plugged the PA speaker into the soundboard and powered the board with a portable phone charger. I then grounded each pin to see how it sounds through the speaker and verity the soundboard would work.

Step 2: Buttons

Next I connected three push buttons to the sound board. I collected all ground wires into one common ground (with the wire nut in the picture) and connected that to the ground pin on the sound board. I then soldered the other wire from each button to one pin each on the sound board.

For the button housing I took a piece of scrap wood, drilled three through holes, and dropped the buttons in.

Step 3: Wiring

I know it's a bit messy, but check notes on the image for details.

The system is powered by the 12V plug in the car. Even though the plug delivers 12V, most phone chargers need 5V so I had to buy a special plug that does not contain a converter.

The amp and sound board have different voltage requirements so the power cord is spliced. 12 volts run directly to the amp for power, while the other side goes through a 12 to 5 V converter to reduce the voltage for the sound board. The sound board connects to the amp with the analog audio cable seen here.

Not pictured here is the PA speaker, which connects to the output of the amplifier. I had to cut the PA speaker wire and splice it to the speaker wire that came with the amp. I mounted this speaker under the hood using two conveniently placed holes that were already there. It took me a bit to get through the firewall and into the engine compartment, but I found a hole behind the pedals near the steering column.

The second picture shows everything laying in my seat once connected. Here I did a test run to make sure everything worked before installing it.

Step 4: Final Installation and Test

I opted to put all components in this space in the center console to avoid removing any of the plastic trim. I could have hidden components and placed the buttons in the empty spots behind the gear select, but I didn't want to risk breaking the plastic or have anything permanently in place. Everything seen here could be pulled out within a few minutes if needed.

The button housing is held in place with strips of self-adhesive Velcro.