[PD] Data in audio / modem
hans w. koch
hansw.koch at gmail.com
Sun Aug 20 11:18:55 CEST 2017
how about encoding it normalized to 0. - 1.as amplitude in 3 sinewaves, about 1 octave (or better some non-harmonic spacing) apart and then separating the sinewaves with sigmund or fft?
probably depends on how much precision you need to have.
cheers
hans
> Am 20.08.2017 um 09:59 schrieb cyrille henry <ch at chnry.net>:
>
>
>
> Le 19/08/2017 à 23:18, Max a écrit :
>> On 2017년 08월 19일 23:03, cyrille henry wrote:
>>>> If I'd would want to encode (sensor) data in an audio signal, how would I go about that?
>>>
>>> if the sensor output analog value, i'll just use 2 AOP : 1st one to create saw waveform and the 2nd one as a comparator to create a PWM rectangle wave.
>>>
>>> in pd side, you can use >~ 0 and a lop~.
>> I'm not sure I understand. What's an AOP?
> sorry, I mean OPAMP (AOP is the french term)
> This solution is to convert the analogue value to high/low ratio of a rectangle wave
>
>
>>> if you want somthing more reactive, you can encode the sensor valuee in a frequency (using a VCO)
>> Like a pair of osc~ and sigmund~ (attached)?
> in your example, the sensor change the amplitude of the signal. Since you where asking for "a volume independent solution", I propose changing the frequency of the signal.
>
>
>> I need 3 values of 7 bit in one channel.
> oh, 3 sensors on a single audio channel : it's a bit much for a simple solution. At least using only analogue electronics.
>
> if you have a digital system to encore the data, you can use a PPM signal.
> https://en.wikipedia.org/wiki/Pulse-position_modulation
> http://www.fpv-hero.de/Images/PPM1.jpg
>
>
> You can also send value as serial data at 9600 b/s
>
> can you tell us more about your setup?
> why can't you use usb to get the value?
>
>
> cheers
> c
>
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