Saturday, 13 March 2021

Marf 248r - Rev one - external clocking

 I love my Marf(s) 248r.
They are sadly not originals but I find them still so very useful.
I've always found external clocking a bit fiddly. Esp the early rev1.
The rev2 has had firmware updates which I believe has improved this issue.
The rev 1 (as far as I know) hasn't had any software updates so the issue persists.

This is how I used to clock it.


You can use any clock source such as the 259 in the video.
The base patch is that you must plug your clock into the start jack.
The stop jack is plugged into the all pulses out jack.

So every time a clock pulse is sent to the 248, it advances. The AllPulses jack then sends out a pulse
which stops it. The cycle continues.
 

The only issue is that the marf misses a step.
It seems that the pulse from the "All Pulses" isnt quick enough.
 
 The solution was really staring me in the face.
Use two clocks.
One must be twice the speed of the other.
You can use a clock divider/ multiplier. Something like a 281, 0r 284 should do nicely.

The slower clock is your master.
The faster one takes the place of the "Allpulses" jack.
The clock isn't perfect, and its still quite fiddly trying to work out the correct divisions.
 
Sometimes, the marf will jump a step, but it doesn't happen too often.
I kinda like that odd bit of uncertainity.
You need to make an envelope with a rise time slower than the clock
 The quad function generator really is a very useful module. Don was a genius.
The 281, 280, 284 etc are all great.
They can be set to behave as 4 synced clocks each with a division or multiplication of the others.
Or you can let them run at different unrelated speeds for some crazy patterns.
 

Buchla Clock Dividers

 Clock dividers in the Buchla Universe.


Use the 246/245 sequencer's odd or even outs

 Actually most Buchla sequencers will let you do this. You can make odd divisions with a Buchla 251e
for example.

 

 

 

 

 


281e, 281, 284

Make an envelope with a rise time slower than the clock
 The quad function generator really is a very useful module.
It can be set to behave as 4 synced clocks each with a division or multiplication of the others.

 

 

 

 

 

 

 


Pendulum ratchet

 Eardrill

 

 

 

 

 

 

 


Intellijel MM ustep

 

 

 


 Sputnik 244 sequential switch

 

 








Time & Triggers - 2TT
Based on the Temps Utile & Mutable Instruments
Branches (Bernoulli Gate)










K4816 Pattern Generator

Kilpatrick Audio









Verbos Electronics

Model 243v Programmable Pulser







Buchla 242

Programmable Pulser










252e
Buchla Polyphonic Rythm Generator






250e

Dual Arbitrary Function Generator













There are probably other modules I haven't thought of.
Shoot me a message, if you have any ideas.

------

One of my readers (Kyle) suggested these modules:

"The 248 MARF & the sample and hold section on the 266 Source Of Uncertainty can 
divide a pulse by two, and the Polyphonic Adaptor section on the 264 Quad 
Sample & Hold can be used to divide pulses by 2/3/4."

Cheers Kyle.

Arduino Workshop - Wollongong Uni

The Maker's Space at Wollongong Uni, is doing Arduino classes.
Really enjoyed the first workshop last Thursday.

The  classes are intended to be a basic introduction into the world of Arduino
The first class was the obligatory flashing LED tutorial.
I'm not intimidated with standard electronics, but what has in the past slowed my entry into the world of Arduino is the programming aspect.


The classes make use of TinkerCad
It's a really good way to trial your projects before building them in the real world.
 

 
 


TinkerCad is also an easier way to learn programming.
It gets started with code blocks.
These are pre-written blocks of code which you can drag, drop, rearrange.















You are encouraged to search the web. These classes are just designed to get you stared.
 The pic below is a MIDI output for Arduino

 
Korg Littlebits


Makers space also has some 3D printers and lazer cutters which I will most likely find useful in the future.


The next class will focus on LED strip lights
 

Links
+ https://www.makeuseof.com/tag/getting-started-with-arduino-a-beginners-guide/
 
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Arduino - Hardware - Getting started

Some basic Arduino info to get things started.
There are plenty of different types of Arduino board. 
Here is a comparison of the Leonardo to the Uno
The Uno is the most popular, but the Leonardo is still a good choice


Arduino Leonardo Arduino Uno
Microcontroller ATmega32u4 ATmega328
Digital I/O Pins 20 14
Analog Input Pins 12 6
PWM Channels 7 6
Flash Memory 32 KB of which 4 KB used by bootloader 32 KB of which 0.5 KB used by bootloader
SRAM2.5 KB 2 KB
  Arduino Uno
This is the most common type of Arduino

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Analog Pins
A0 to A5
These are analog pins but can also serve as digital ins/outs
On the Arduino Uno they can sense a range of input voltages. 
You might use this to read the position of a potentiometer or 
another input with a smoothly variable input.  
 
These pins are connected to a ADC (analog to digital converter) .
The ADC has 10-bit resolution, meaning it can represent analog voltage by 1,024 digital levels. 
The ADC converts voltage into bits which the microprocessor can understand.
0V = 0 bits
5 V = 1023 bits

Pins A4 & A5 are also the I2C connections.
SCL on A5, SDA on A4
The I2C bus allows connection of multiple modules, allowing communication between them.
With I2C there are 2 wires referred to as SCL and SDA.
  • SCL is the clock line which is designed to synchronize data transfers.
  • SDA is the line used to transmit data.
 
 
Digital pins
Pins 0-13 of the Arduino Uno serve as digital input/output pins.
Digital is a way of representing voltage in 1 bit: either 0 or 1.  (High/Low).
When the digital pins are configured as outputs, they output either 0 or 5 volts.
When the digital pins are configured as inputs, the input voltage is converted into either 0 or 1.
Any input voltage below 0.8v - considered as 0.
Any input voltage above 2v - considered as 1.
 
D0 - Serial TTL (RX)
D1 - Serial TTL (Tx)
D2
D3 - PWM Pin
        PWM allows you to control the voltage of the output by switching the output 
         between high and low very very quickly. 
        The percentage of time the pin is high is called its 'duty cycle' 
          the PWM enabled pins produce a constant frequency of ~ 500Hz,
         while the duty cycle changes according to the parameters set by the user.
          This pin does "analogWrite" as do pins 4,5,9,10,11
          These pins allow you to simulate analog voltages
D4
D5 - PWM Pin
         +This pin does "analogWrite"
D6
D7
D8
D9 - PWM Pin
D10 - PWM Pin
D11 - PWM Pin
D12
D13 
The Arduino Uno R3 has an LED with its own resistor attached to pin 13. This means that even if you don't attach any LEDs to your board, if you set pin 13 to an output and set it high, you should see an LED on the board come on. Digital pin 13 is harder to use as a digital input than the other digital pins because of this LED and the resistor attached to it
 
-------------------
 
SPI Pins: SS on 10,  MOSI on 11, MISO on 12, SCLK on 13.
Serial Peripheral Interface (SPI) is a serial data protocol used by microcontrollers to communicate with one or more external devices in a bus like connection. The SPI can also be used to connect 2 microcontrollers. 
  • MISO (Master In Slave Out) - A line for sending data to the Master device
  • MOSI (Master Out Slave In) - The Master line for sending data to peripheral devices
  • SCK (Serial Clock) - A clock signal generated by the Master device to synchronize data transmission.
 
 
Arduino Leonardo
Regular
Microcontroller: ATmega32u4 with built-in USB communication.
It has double the number of analog input pins. 
A0-A5 are dedicated for analog, and A6-A11 are on digital pins.
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Analog Pins
A0 to A5 - these are on the analog in header
A6 to A11 - they are located among the digital pin headers.
These analog pins can also be used for digital I/O.
 
Digital pins (18 digital pins)
D0 - Digital In & Serial In,  RX
       Because this is a digital input, it can only read if a signal is on or off.
       It can receive digital info from another module, and can allow two arduino modules
       to talk to one another.
D1 - Digital out & Serial out, Tx
        Both the TX and RX pins have LEDs associated with them so show
        the status of Serial communication between the board and the computer.
D2
D3 - PWM Pin
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14 – MISO – PB3
       Its also a ground.
D15 – SCK – PB1
D16 – MOSI – PB2
        Also I2C's SDA
D17 – SS – PB0
       Also I2C's  SCL
 
Pin D17 (SS) does not have a corresponding pin on the ICSP header, nor anywhere on the board. In order to use it, you must solder a wire to either the end of the Rx LED or the via attached to it 
 
 
Little Bits (leonardo)
This is a really easy way to get into Arduino.
Korg released this a few years ago and these modules are geared towards analog synths.
Though they may look like toys, the modules are a fun way to do DIY without needing to touch a soldering iron.
 
All the inputs are on the left.
The outputs are on the right.
 There are 3 inputs & 3 outputs.
 
Little bits reads voltages a bit differently than a standard arduino.
The input voltages are the same (zero to 5Volts) but
little bits reads a 5V voltage as 99 bits, where as an arduino reads it as 1023 bits.
So in the code, if you wish to convert to little bits remember 5V = 99

With output voltages its the same deal.
With little bits, the output is 0 to 99
In arduino, the output values are 0 to 255
 

 
 








Analog/Digital In/out Pins
A0 - Analog input
         It can be used in analog or digital read.
A1 - Analog Input
          It can be used in analog or digital read.
A2 - A4 - solder a header to this to allow external connections.
       These 3 pins are GPIO (general-purpose input/output) analog 
A5 - (N/C... not connected)        
 
Digital pins
D0 - Digital In & Serial In,  RX
       Because this is a digital input, it can only read if a signal is on or off.
       It can receive digital info from another module, and can allow two arduino modules
       to talk to one another.
D1 - Digital out & Serial out, Tx
        Both the TX and RX pins have LEDs associated with them so show
        the status of Serial communication between the board and the computer.
 
D2 - I2C Bus Digital I/O
D3 - I2C Bus Digital I/O
         The I2C bus allows connection of multiple modules, allowing communication between them
          without needing the bitsnap connectors
         The top side of the PCB has two pads which break out pins D2 and D3 from the ATmega32U4. 
         These are the SDA and SDL lines used in I2C communications so multiple boards can be 
         chained together. 
         There are unpopulated pads for 10K pull up resistors if I2C implementation is needed. 
          These pins can also be used as GPIO (general-purpose input/output).
 
D4 - (N/C)
D5 - Digital PWM Out 
        This output has a output mode switch that allows you to select between PWM vs analog config.
        In analog mode, the output is sent through a LPF (Low Pass filter) to improve compatability with
        analog signals in the littlebits system.... basically, it simulates an analog DC voltage
D6 - (N/C)     
D7 - (N/C)     
D8 - (N/C)     
D9 - Digital PWM Out 
         This output has a output mode switch that allows you to select between PWM vs analog config.  
D10 - Digital I/O - solder a header to this to allow external connections.
D11 - Digital I/O - solder a header to this to allow external connections.
D12 - (N/C)     
D13 - Digital I/O - solder a header to this to allow external connections.
 
ICSP header - 6 pins
ICSP stands for In-Circuit Serial Programming.
Allows you to change the bootloader or program the module directly from this header with an AVR programmer.

When connecting an output little bits module (W9 proto):

Links (Paul McWhorter)

+ Basic blinking LED video and starter programming

Understanding Arduino Variables  
 
Understanding and Working With Binary Numbers
 
Building a binary counter with LEDs
 
AnalogWrite command
 
Understanding PWM and the AnalogWrite command
 
Understanding How To Read Analog Voltage using analogRead Command
 
 
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Saturday, 6 March 2021

New Atlantis - Modular Synth event

 Thanks to Adam for hosting this.
Last night, New Atlantis was exploring quadraphonic electronic music.
 
 
 
Was great to be out and about again after all the shutdowns of 2020.
 
 

NSW has had more that a month of double doughnut days (zero local cases and zero cases in hotel quarantine within a 24-hour reporting period)
Hopefully there will be more synth events to come

Monday, 1 March 2021

Andromeda A6 - Alesis Part 4 - Filters, the post filter mixer.

This is part of an earlier series of posts on the Andromeda Synth.
The earlier posts are here:
 
The A6 has two filters:

Filter 1 is a 12db multimode 2-pole.
It was designed to emulate the Oberheim® Synthesizer Expander Module™ (SEM) which was introduced in the mid 1970’s. It has four fully adjustable modes: low pass, high pass, band pass and notch, just like the original SEM
 
Filter 2 is a 24db 4-pole lowpass. It was designed to emulate the Moog® modular synthesizers introduced in the late 1960’s.

Each filter has four pot controls, 3 mod inputs and a view button.
The pots set the Cutoff frequency, Resonance, ENV 2 and Key tracking.

Key tracking will vary the filter frequency across the keyboard.
 
 
 
 
 
 
 
 
 
 
Notice that the two filters can be connected to each other. 
There are 4 settings: Off, Mix, Notch & BP.
 
Off
FILTER 2 receives no input (but it can generate tones on its own when in full resonance).
 
Mix
When filter 2 input is set to mix, both filters are working in parallel.
That is, both filters are independent.
Thus the LP,BP, HP of filter 1 & the LP of filter 2 are all available at the same time
 
Notch
FILTER 2 will filter the output of FILTER 1’s notch filter(Low Pass and High Pass).
 
BP
FILTER 2 will filter the output of FILTER 1’s band pass filter
 

The Post Filter Mix


Each of the filter outputs has it's own filter level input pot.
They each also have mod inputs  
 
Notice the BP invert and the extra Pre-filter inputs -
 the sines from OSC 1 & 2 and the ringmod.

BP invert will change the BP filter into a fixed width
band reject filter. 
Thus the Filter Cutoff frequency control will raise or lower 
the centre of this band.

 

 

 

 

 

 

Filter 2 self oscillation

 It's a classic Moog style filter so can self oscillate. (Filter 1 can't).
 FILTER 2 receives no input but it can generate tones on its own when in full resonance.
Set key track to 11O'clock and turn all outputs from filter 1 to off.
Resonance to full clockwise. 
The sound is a simple sinewave.
Press any key on the keyboard.

Filter Feedback

Filter feedback is a popular "trick" of many synths.
You plug the output of your headphone jack into the filter input.
This overloads the filter & gives a gritty, nasty sound 
The button is in the pre-mix section.
The noise level adjustment is the filter feedback.


MUdgee - NSW - Australia

 Some pics from a trip to Mudgee, NSW.

It's my Fav place for red wines.

Mudgee is a town in the Central West of New South Wales, Australia. It is in the broad fertile Cudgegong River valley 261 km north-west of Sydney and the centre of the Mid-Western Regional Council local government area. 

 


Love the Cellar Door tastings

As at June 2018 its population was 12,410. Wikipedia

 Grapes were first grown around Mudgee from 1858



Large wineries started planting again from 1974. Mudgee grows predominantly red wine varieties, especially Shiraz, Cabernet Sauvignon and Merlot.

 

Mudgee Town

The Paragon Hotel is your classic local hotel with beer garden and front verandah









Links

Bottom of a Hole - Larry Niven


At the Bottom of a Hole", short story review
First published: Galaxy Science Fiction, December 1966.
 
Beware there are some spoilers in this piece. 

This is the third in a series of short stories by Niven about the first Martian explorations. 
It's not an independent story. It's good if you have read the previous ones in this trilogy - "How the Heroes Die"; & "Eye of an Octopus".

The story starts on April 20, 2112 

Humanity has explored The Moon (Luna), Mercury, Venus, Mars & the outer planets like Pluto.
 
There is a huge community living among the asteroid belt of Earth's solar system (Sol System). They seem to be mostly miners & call themselves "Belters". Born far from Earth, and living most of their lives in the depths of space between Mars & Jupiter, Belters are fiercely independent.

 
 
 
 
Earth is ruled by the UN (United Nations).  Mar's doesn't seem to hold much significance for Humanity. Man last visited the red planet about 70 years ago.
 
What struck me about Niven's world building was how close his vision is to that portrayed in the Sci Fi series, "The Expanse".
 
However, in "The Expanse", Mars is a superpower with influence equal to Earth, and the Belters are caught in between.
 
 
 The main character in this novelette (Muller) is a Belter, so it's useful to know a bit about them. 
 
The Belt possesses valuable ores, which are easy to extract due to the nonexistent gravity.
This region was originally under UN control, but is now independent.
Belters live among the asteroids and make their living by mining the ores. 
 
A few quotes from "Bottom of a Hole":
 
" Belters don't need houses. A Belter’s home is the inside of his pressure suit".
 
 "In the Belt smuggling is against the law, but it isn’t immoral. It’s like a flat- lander (man from Earth) forgetting to feed the parking meter. There’s no loss of self-respect. If you get caught you pay the fine and forget it.”
 
"Belters learn to avoid gravity wells. A man can get killed half a dozen ways coming too close to a hole. A good autopilot will get him safely around if, or program an in-and-out spin, or even land him at the bottom, God forbid".  "

This last quote is important. The title of the story is "Bottom of a Hole". 


It's kind of a murder mystery tale.
Muller is a smuggler, and a native of the Belt. He is heading towards Luna but finds himself having to visit
Mars in order to evade a government vessel that is chasing him. His ship is damaged on landing and he has to visit the old human settlement of Bubble Town.

He finds the settlement untouched for 70 years. It is strewn with corpses and he tries to unravel the mystery by reading the crew's old journals and doing some personal detective work.
 
 
 
 
 
 
What bother's me about this story is why no one from Earth returned to rescue these early travelers.
Was there no communication from Earth mission control ?
 
Niven is really good for his Hard Sci Fi. even if modern day discoveries disprove some of scientific knowledge from the 1960s.

He goes into quite a lot of detail about all manner of things such as the Martian surface.
 
"The dust is like thick oil. The moment I stepped onto it I started to sink. I had to swim to where the crater rim slopes out like the shore of an island. It was hard work".
 
"It's meteor debris from vaporized rock. On Earth, dust this fine would be washed down to the sea by rain and turned to sedimentary rock, natural cement. On the Moon there would be vacuum cementing, .......But. here, there’s just enough “air" to be absorbed by the dust surface ... to prevent vacuum cementing . . . and not nearly enough to stop a meteorite. Result: it won’t cement"
 
 
 
 

Without spoiling too much of the story, Muller does piece together the murder mystery.
 

He also does meet the local Martian natives. A battle takes place.
 














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More by Larry Niven:

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sci Fi Index

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