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Auto-Seq Documentation

Written April 6th, 2014

I. Using The Module

A. What is Auto-Seq?
B. Controls/Inputs/Outputs
C. Sample Patches

II. Schematics

A.Chip Pinout
B.Inputs

1.Analog Inputs
2.Digital Inputs

C.Outputs

1.Analog Output
2.Digital Output

D.Power Supply

III. Construction

A.Parts List
B.Wiring/PCB Information
C.Calibration

Summary of Contents for Auto-Seq

Page 1: ...ule A What is Auto Seq B Controls Inputs Outputs C Sample Patches II Schematics A Chip Pinout B Inputs 1 Analog Inputs 2 Digital Inputs C Outputs 1 Analog Output 2 Digital Output D Power Supply III Construction A Parts List B Wiring PCB Information C Calibration ...

Page 2: ... It selects by octave ranging from one to five octaves When the sequencer is choosing notes it will check to see if a note is in range and if not it transposes the note down an octave So when increasing range you will hear the same notes just in different octaves 5 The One Switch When activated this switch will make sure that a note is played on the first note of the sequence the one of the sequen...

Page 3: ... of a VCF and the amplitude of a VCA The Voltage output is being sent to a VCO and VCF The VCO s output is being sent to the VCF whose output is being sent to the VCA For the third sound sample this same patch is used but the clock is also controlling a pair of drum sounds Listen to example 1 here This mp3 just demonstrates a few different sequences being created by hitting the New Sequence button...

Page 4: ...s which look for changes between 0 and 5V Pins 5 7 are digital outputs which output a change bewteen 0 and 5 volts Pins 8 9 and 11 are serial data outputs which connect to the digital to analog converter chip B Inputs 1 Analog Inputs On the right we see the four analog inputs Each of these consists of a 100K linear pot wired as a potential divider between 5V and Ground The wiper of the pot is conn...

Page 5: ...will turn the input on The positive inputs of each is tied to ground through a 100K resistor and then attached to the input jack except for the New input which first goes through a diode to protect the output of the driving circuitry from the New switch The outputs of these op amps each go through a diode for polarity protection then a 100K resistor in series with a schottky diode for overvoltage ...

Page 6: ... into a pair of inverting amplifiers one of which has a trimpot in it s feedback path This provides for a non inverting adjustable amount of amplification 2 Digital Outputs The digital outputs are pictured above Each circuit is composed of the same pieces An op amp is wired as a unity gain buffer with it s input tied to a digital output pin of the microcontroller The buffer s output is then sent t...

Page 7: ...hesizer systems The positive and negative rails are filtered by a 10 ohm resitor and 10uf capacitor and then again at the pins of the TL074 with 1uf bypass capacitors The 5V supply for the controls and the microcontroller is obtained with a 7805 voltage regulator Shown are wiring pads for 5V and GND to connect to the jacks and buttons ...

Page 8: ...g 1 4w Metal Film unless otherwise noted on all resistors 1K ohm 7 100K ohm 6 33K ohm 1 100K bussed array 1 11 Pin or stand 10 resistors on their end and make your own B100k Pot 4 16mm PC mounted Alpha brand 100K trimpot 1 Multi turn cermet Capacitors Value Qty Notes 1uf 9 2 5mm lead spacing use cheap ceramics 10uf 3 2 5mm lead spacing Electrolytic Other Value Qty Notes 8 pin Dip socket 1 14 pin D...

Page 9: ...leswitch K Input for the Key control wire to the bottom tab of a toggleswitch C Input for the Clock input wire to the Clock input jack R Input for the Reset input wire to the Reset input jack N Input for the New input wrire to the New pushbutton V Output for the CV voltage wire to the CV output jack T Output for the trigger out wire to the Trigger out jack G Output for the gate out wire to the Gat...

Page 10: ...all the knobs completely clockwise then turn the power supply on The module will now be in calibration mode 2 Use a voltage meter to read the CV output 3 Adjust the trimpot until the CV output is exactly 6V 4 You re done Moving the knobs to any other position should take you out of calibration mode ...

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