To convert my analog voltages coming from my peak detector circuit to digital signals I used the ADC0804LCN. (Click on the picture of the chip to purchase)

 

As the Raspberry Pi micro-computer only accepts digital inputs, this component is necessary. The diagram of how the chip is wired up can be seen below also. The majority of the pins are connected to the General Purpose Input or Output pins of the Raspberry Pi (GPIO).

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The timing diagram from the datasheet shows how the ADC should be clocked in order for it to work. This clocking control is all done within the Python code on the Raspberry Pi. This is discussed in the Raspberry Pi section