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Author Topic: Devices controlled by SOUND. LTC1799 Attiny85 (arduino ) and digital pot.  (Read 3044 times)

the beast

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Long time since I've posted here, because I'm on so many Facebook CB boards right now. 

I still have love for everyone here, though!!

A bit complicated to explain, but SUPER simple to implement.  Right now the code is just for the attiny, but I'm working on a vanilla Arduino/Atmega port as well

The audio source goes into the ADC of the microcontroller, gets reduced to 8 bit, sent out of the SPI out of the Atttiny.
Then that controls the steps/wiper of the digipot.
This makes for a very cheap 2 chip ADC/DAC based bit crusher.


The thing that makes it unusual and useful is that in addition to being useful as a cheap and dirty ADC/DAC combo solution is that the stepped resistance of the digipot (which is what lets it work as a low quality DAC) also allows for control over a chip called the LTC1799.

As we all know, The ltc1799 is a resistance controlled square wave generator.
It has an effective range of 100khz to 33mhz.

I'm effectively over/underclocking these devices with an external clock.
So the process is -figure out min/max boot clock speed of device, setup a resistor going to the digipot.
The analog in of the microcontroller effectively controls the clock speed of the device in question.


The DAC action was just to test the input chain of the device.
Fun thing about doing it this way is that you can then use any sensor data to control clock speed/voltage of any number of things. 

The digipot and the Attiny cost less than $4, and the LTC1799 costs about $4.00
So for a few dollars, you can modify any digital device or any device that relies on a high clock speed.
The other thing I've done is create 8 bit wave tables to control the modulation effect.  These wave tables, if cycled through fast enough create audio level frequencies as well.
It also allows for midi/automation control over pitch/clock of any digital device.

Korg EA1 circuit bent via LTC1779 and Arduino.

Attiny85, digipot ADC/DAC

Ltc1799 and attiny controlling bent Electribe.



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Gordonjcp

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Maniac.
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If at first you don't succeed, stick it through a fuzzbox.

the beast

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