Need a suggestion on fun Horn circuit

Discussion in 'General Electronics Chat' started by Popnfrsh24, Sep 7, 2010.

  1. Popnfrsh24

    Thread Starter New Member

    Sep 7, 2010
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    Hey everybody,

    So I am a senior at Purdue studying Electrical Engineering Technology. For my senior design project, I am controlling an RC car with a gaming steering wheel and gas pedals instead of the regular handheld controller. I am also incorporating a horn button on the steering wheel so that when the user presses the horn button, the RC car will honk.

    Do you guys have any suggestions on what kind of circuit I should build for the horn circuitry? What I thought would be cool is if the horn was kind of like an ambulance. So, it sweeped through a range of frequencies instead of outputting just one sinusoidal frequency. I thought I remember doing this with the XR2206 IC chip before, but I got pretty confused when reading the datasheet. Does anybody know if this is possible?


    And another thing, I am planning on using a micro to control whether the horn is on or not, so do you guys know how I would incorporate the micro to enable/disable the horn?

    Thanks,

    Joey
     
  2. Dyslexicbloke

    Active Member

    Sep 4, 2010
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    Given the complexity of the reading the gaiming controlls and translating that into a 'standard' multy channel RC radio signal I am a little confused as to why you are asking this, however
    You can make pretty much any sound you want by modulating and re modulatiing signals with multiple oscilatorts. if you want a swept signal at least one will have to be a voltage controlled oscilator that you can feed with the sweepperiod from anotherv one.
    However if you have a 'Micro' onboard the RC car you could simply program the sound you want on one of the pwm outputs or even bit bang on a standard IO pin.

    Hay ... why not do some engine noise at the same time?
     
  3. retched

    AAC Fanatic!

    Dec 5, 2009
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    Clip on one of those canned air horns. Like the ones used for sporting events.

    Use an actuator on the car to depress the horn button.

    That will be loud.

    As for anything else, you could use a simple MP3 IC to play a recording of whatever sound you want..be it a ambo siren or engine noise.
    the MP3 ICs these days contain EVERYTHING. Just attach a speaker and your set.

    There are many that can be controlled via uC, so the onboard uC could trigger the MP3 player IC when the "horn" signal is received.
     
  4. Popnfrsh24

    Thread Starter New Member

    Sep 7, 2010
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    Thanks for the input guys.

    @retched, do you know what type of MP3 IC I should be looking for? I did some searching, and I found a lot of MP3 decoder ICs, is this what I need? And, are you saying that these ICs already come with whatever sound I want on them, or would I have to download the sound to the IC?

    If the MP3 ICs are not terribly expensive, I might go with that route. But I am liking the idea of using my micro to output this sound just because I don't have to buy anything. I don't have ANY experience doing anything like this with a micro, does anyone know if it is hard or not? I have looked around at some articles and is the general concept to just download the sound file to the micro's memory (what type of file is this?) and then output it on a certain pin of the micro? Then you just use an amplifier to bring it up to an audible level?

    If anybody could help me with this, or help me find some documentation that would steer me in the right direction, I would greatly appreciate it. Also, just for your guys' information I am using a Cypress PSoC microcontroller.
     
  5. retched

    AAC Fanatic!

    Dec 5, 2009
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    Often the MP3 ICs need an external memory..like an EEPROM on even a SD card to hold the "songs".

    It is possible for you to use your micro IF IT has a D/A converter.

    You could digitize the sound you want played (via A/D converter) and that could be stored in flash memory if you had enough available on chip.

    Then you play it back through the D/A converter to a speaker.
     
  6. Popnfrsh24

    Thread Starter New Member

    Sep 7, 2010
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    My micro can have both a DAC and ADC on it. But, would there be a way of skipping the whole ADC step and just find a sound file online to use, and just download that to my micro and store it there? Could I do that, or would this sound file be erased every time I turn the power to the micro off?
     
  7. retched

    AAC Fanatic!

    Dec 5, 2009
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    It would depend.

    If the file you got was an MP3 (or any other encoded filetype) you would need to DECODE it before playing it.

    You would need a sound file that was RAW, and recorded with the same bitrate that your DAC can 'understand'.

    If I record my car's horn at 24bits, you will not be able to play it through an 8bit DAC.
     
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