The Post-Moog Digitally Controlled Analog Synthesizer Group Members Logan Snow Robert Estelle Greg Hartl Toan Ho

 Technical Objectives  Create a modular audio synthesis system  Support MIDI input  Create an innovative user interface  Support storage and recall of presets  Maintain a low material cost  Motivation  Target hobbyist musicians and synth enthusiasts  Recreate classic analog sounds

Product Cycle CostsQuantityUnit PricePrice VCO1$18.00 VCA3$15.00$45.00 VCF1$17.00 Noise Source1$15.00 Digital Control Board2$30.00$60.00 System Interface Board3$20.00$60.00 Interface Knobs12$6.00$72.00 Shipping3$30.00$90.00 Greg's Hours136$25.00$3, Logan's Hours136$25.00$3, Robert's Hours136$36.00$4, Toan's Hours136$25.00$3,400.00

Digital Control Board System Interface Board Analog Synthesis Hardware User Interface MIDI Keyboard Debug Monitor Output Amplifier

P1P2P3P4 Save AttackDecaySustainRelease Pulse Width Resonance Vibrato Mode ModulationVariance Center Volume Filter Options Filter LPF BPF HPFFixed Sine Tri Noise Sine Saw Rect Tri Level Duration

 Each digital rotary encoder is read by a dedicated microcontroller (PIC16F87)  LEDs indicate position of knob to user  Display can be reset by master microcontroller to indicate new position PICTURE HERE

MIDI Input Master Microcontroller (PIC24FJ64GA002) Debug Port Rotary Knob Connectors SIB Connector DACs

 Microcontroller reads inputs:  MIDI from external music device  Rotary knob positions through I 2 C  Debug commands from serial port  Microcontroller sets outputs:  LED positions using I 2 C LED drivers  Analog control voltages using I 2 C DACs  All digital control occurs on two I 2 C busses

MIDI Keyboard Master Microcontroller Slave Microcontroller I2C DAC … … VCO Control Filter Resonance Other Control Voltages … LED Driver … Debug Monitor LED Driver

VCA6 VCA1..4 VCA5 VCO VCF Noise Output + I’m a big picture of the SIB Receives control signals from the DCB Connects to the power supply Routes all signals between the analog boards Mixes the intermediate signals

VCO VCF VCA1..4 VCA5Noise Output VCA6 +

VCO VCF VCA1..4 VCA5Noise Output VCA6 + VCO 1V/Octave control input At least 3 Octave range Several Outputs: Sine wave Sawtooth wave Rectangular wave with PWM Triangular wave Each output has corresponding VCA I’m a big picture of the VCO

VCO VCF VCA1..4 VCA5Noise Output VCA6 + Noise I’m a big picture of the noise source White noise Adjusted through a VCA before mixing with other signals

VCO VCF Noise Output + VCA1..4 VCA5 VCA6 I’m a big picture of the VCA Logarithmic amplitude control voltage Three boards with two amplifiers each VCA1..4 modulate VCO outputs VCA5 is dedicated to the noise source VCA6 output connects to final synthesizer output

VCO VCF VCA1..4 VCA5Noise Output VCA6 + Voltage-controlled resonance and center frequency Multiple Filter Outputs High Pass Low Pass Band Pass I’m a big picture of the VCF VCF

VCO VCF VCA1..4 VCA5Noise Output VCA6 +

ComponentCompletedTested Voltage Controlled Oscillator Voltage Controlled Amplifier (x6) Voltage Controlled Filter Noise Source System Interface Board Digital Control Board Master Microcontroller Software Rotary Knob Assembly (x12) Slave Microcontroller Software Chassis/Panel

 Shipping problems  Solder flux disaster  Old SIB revision sent for fabrication  Post-fabrication board modifications  Pin size mismatches on DCB

 MIDI input from a music keyboard  Auditory verification of audio parameter manipulation  Visual verification of user interface correlation with audio parameter adjustment  Saving and loading of presets