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Arduino based car start-up sounds


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Get ready for this:

I'm wanting to make an Arduino controlled brain that I would tie into a car's audio system. some cars beep/bong/whatever when you turn the car fully over. Well this brain would be able programable to have whatever tone you want in place of the bing/bong/ting (whatever). My idea (Doctor Who fans, get ready) I want to have the Tardis sound play whenever I start my truck, for example.

Anyone have any ideas? Not wanting to set this project in stone (yet), but just an idea I've been rattling in my mind for a while.

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You mean like the noise a car makes when the keys are in the ignition but the door is open kind of sound? Not sure where that sound even comes from or plays through, but I could see maybe like an rfid tag type thing that when the ignition turns, passes a reader and maybe the sets off the reader to the arduino and plays your custom sound. Something like that or maybe just a switch tied into the ignition somehow that triggers some sort of passive switch to send a signal to the arduino. Any mechanics on the forums know how to tie into that or where the chime sound comes from on most cars?

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  • 1 month later...
Any mechanics on the forums know how to tie into that or where the chime sound comes from on most cars?

I'm not a professional mechanic but I know how to install a car stereo (having done it for myself 4 time on 3 different car brand).

All the habitacle sound you hear come from your original radio, there a few signal line comming from the BCM of your car to the Radio, when you change the radio, you have to buy a convertion kit that will take these control line and feed it to the always on AUX port of the radio.

For your project, you should get your hand on this convertion kit for your specific car make and fool around, reverse engeneer it... its probably jsut a PIC that check for signal and output chime...

From there you can either reuse existing signal (door open, contact in...) or add your from a switch or sensor

Hope this help

EDIT: here's the step I would make to reverse engeneer it

- Grab a buspirate or a protocol analyser that support CAN protocol

- Get the repair manual of your car make

- Find the control line from BCM to Radio

- Triger various chime and sniff the data.

- Write an arduino code that understand the data and output chime

If you have the original radio:

- Get a cheap amplifier board and few diode and connect the sound in parallel to speaker (diode are to prevent the car radio blasting the small amp board, its unlikely that the small board can break the radio but be carefull, you can use a relay to switch the speaker from radio to arduino amp if you scared of frying the radio)

- there is no always on AUX in on the original radio

- Connect signal line in parallel to arduino and original radio

If you have 3rd party radio:

- Connect the sound output of the arduino to the always on AUX in port of the radio

- Dedicate signal line to arduino (remove conversion kit) or connect arduino in parallel to the conversion kit (You will lose some sound or have double sound depending on your choice)

Edited by madhak
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  • 3 weeks later...

When you turn on your ignition you are really just supplying ~12vdc to different areas of the car.

You have 4 states:

Off: everything is off

Acc: accessory relay has power, supplying your cigarette lighter port, stereo, etc.

Run: this triggers relays for all of your engine's necessary electrical components. In this state Acc is also active.

Start: this triggers your starter motor and allows your engine to turn over. In this state Run is active but Acc might be switched off as to not overdraw from your battery (depending on your car).

If I were to approach this problem I would break it down into 4 logical steps.

Supply power: I would hook it up to a voltage regulator with a few capacitors to the Run circuit to get a clean 5v line out of the 12v battery line. You could even wire this in to your ignition switch harness directly.

Input: If you pull down the voltage from the Start line and use that as input, if you program your arduino to "arm" when the Start circuit powers up, then trigger the audio when the Start circuit powers down, you can reasonably assume that it wont play the sound until the engine turns over. If your battery starts to die, you might hear the sound a good 20 times trying to get your car to start though.

Output audio: this part is up to you. You could rig up a little amp and a small speaker in the dash if you wanted simplicity, or you can try to hack your head unity. Lots of cars dont have their amps powered while the car is starting to make sure that the starter motor has enough amps. Keep that in mind and be creative.

Turn off: if you do use an amp and speaker in the dash, would make sense to power all that down while not in use.

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