Pitch to voltage converter

Motivation

Pitch (Pulse train) to voltage converter front view.

This is the software driven replacement for my all hardware pitch to voltage converter (link) from my Shakuhachi to Synth project. The software driven approach has the advantage of easily adaption for different frequency ranges. In my case it is the range of the Shakuhachi. To change the range just adapt the software. It is completely temperature independent. The needed input is a pulse train derived from your original signal. You can use my Signal to Trigger converter to provide the pulse train. An offset voltage is added to the V/Oct output to fit the needs of your VCO (Synthesizer).



Specs and features


Implementation

Schematic

Pitch to voltage converter. Microprocessor board  schematic

Pitch to voltage converter: Microprocessor board schematic

Pitch to voltage converter. Control board  schematic

Pitch to voltage converter: Control board schematic

Description:

The incoming pulse train is feed to the microprocessor. IC1 (301-F) prevents the microprocessor from negative inputs. Zener D2 prevents from overvoltage. The trigger starts an internal timer of the microprocessor in input capture interrupt mode. The ticks are counted and the count is then looked up in a table. The lookup table provides the values for the V/Oct conversion. The read value is the send to the DAC MCP4921 which is follwed by a low pass (IC1A, 301-B)). IC2A (301-F) adds the offset voltage and IC2B (301-F) corrects the phase.


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Calibration

  • None
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Building hints

  • The AtMega 328p is running on 20MHz. You have to set the right fuses.
  • - avrdude -p m328p -c avrisp2 -U lfuse:w:0xe7:m
  • - avrdude -p m328p -c avrisp2 -U hfuse:w:0xd9:m

Special parts

  • None

Download

Pitch to voltage converter control board documentation download
Pitch to voltage converter control board Gerber files download
Pitch to voltage converter microprocessor board documentation download
Pitch to voltage converter microprocessor board Gerber files download
Pitch to voltage converter *.fpd file download
Pitch to voltage converter software files download

Pitch to voltage converter front view

Pitch to voltage converter: Front view


Pitch to voltage converter populated PCB

Pitch to voltage converter: Populated PCB


Pitch to voltage converter side view

Pitch to voltage converter: Side view


2020 December V 3.0.1

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