[PD] Data in audio / modem

[cyrille henry]

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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