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|
random241
=========
| Python scripts for harvesting entropy from a random number generator (with an
Americium 241 sample mounted over a webcam sensor as its source).
| This repository also features an OSC enabled SuperCollider (|random241.scd|)
script that can interface with it and a rudimentary python script
(|read_gpio.py| - made for BeagleBone Black) that can be used to further
modify effects on the generated sounds in a live setup.
Requirements:
-------------
For the entropy harvesting script (|random241.py|) you need the following
packages and dependencies installed (names may vary depending on your
distribution!):
- python2
- python2-numpy
- python2-pyliblo
- opencv
- liblo
For |random241.scd| you need |supercollider| installed.
For the remote_control (|read_gpio.py|) you need the following:
- python2
- python2-pyliblo
- |adafruit_bbio|
- liblo
Features:
---------
|random241.py|
______________
- Grabbing of bright areas (aka regions of interest in pixels) above a certain
threshold from a webcam
- Calculation of mean x/y values from regions of interest and conversion to
float range
- Sending of time, x and y values via OSC to predefined host and port
|random241.scd|
_______________
- Receive OSC messages for the creation of SynthDefs with certain pitch,
amplitude, length and loop time, according to coordinates and time sent.
- Receive OSC messages for manipulation of post processing SynthDefs (FreeVerb
for now).
- Ignore OSC messages after a certain amount of SynthDefs created.
- Release (all) SynthDefs after a certain amount of SynthDefs is reached.
|read_gpio.py|
______________
- Read GPIO data from BeagleBone Black (P9_39-42 for now)
- Send sensor data as OSC message to predefined host and port
Build instructions
------------------
| As a showcase I'll demonstrate the creation of my device below.
| You'll need a couple of things to build an |americium241| driven random number
generator (RNG). Read through **all of this** before starting!
.. note::
|americium241| is **not a toy**!
It's a transuranic radioactive chemical element. Respect working with it:
- Do not swallow it
- Don't wear it on your body
- Avoid touching it
- At best work in a safe environment (like a lab)
- Do not eat while working with it
- Keep in a closed steel or aluminium container, when not working with it
| That being said, **I am not responsible for any harm inflicted on you
or your environment due to mal-handling of Americium 241**!
| Don't be a fool, work responsibly!
Materials
_________
Americium 241
+++++++++++++
If you're living in the US, you might still have an
|americium241-ionization_detectors| around. For (mostly) everyone else, there's
the possibility of ordering Americium on ebay!
.. figure:: https://git.sleepmap.de/audio/random241.git/plain/images/sample.jpg
:alt: Americium 241 sample
A small sample of Americium 241 (4mm diameter in a steel casing).
Webcam
++++++
You can use any webcam for this project. There are some things to keep in mind
though:
- You will break it!
- Don't use cameras below 2 megapixels (your resolution won't be of any use)
- Make sure you'll be able to open it up and remove its lens!
In my case a Mustek Gsmart Mini 3 has been used, because
|github-gabriel_zoeller| wanted to get rid of his and it was broken in just a
beautiful and fitting way (with the lens already removed):
.. figure:: https://git.sleepmap.de/audio/random241.git/plain/images/gsmart_mini3.jpg
:alt: Gsmart Mini 3
Mustek Gsmart Mini 3 with lens removed.
.. note::
| The Gsmart Mini 3 is not a webcam, although it can be used as one, if you
press a button on the backside of it, while connected via USB.
| As I don't want to open a box and press a button on a camera with an
Americium 241 sample in it, every time I want to use it, I had to solder a
push button switch to it.
| That turned out to be quite a messy job (because the button is very tiny
and so are its contacts on the board).
| If you end up with the same model of camera, do this first, before you
place the sample on top of the sensor chip!
Casing
++++++
| Make sure you'll have a proper casing around for the sample to store in and
later for the camera and the sample to store (or build into for that matter).
| I used a steel casing from an old 19" server rack power supply, that was
trashed at work:
.. figure:: https://git.sleepmap.de/audio/random241.git/plain/images/casing.jpg
:alt: Casing
Casing sourced from old 19" rack server power supply.
Building the RNG
________________
It is highly recommended to use nippers when handling the Americium 241 sample:
.. figure:: https://git.sleepmap.de/audio/random241.git/plain/images/sample_on_steel.jpg
:alt: Americium 241 sample on steel
Americium 241 sample on steel.
The lens mount has a certain diameter. To not have the sample fall on top of
the camera chip, I drilled a hole into and cut out a piece of steel to be used
as a curb for the sample.
.. figure:: https://git.sleepmap.de/audio/random241.git/plain/images/sample_with_curb.jpg
:alt: Americium 241 sample with curb
Americium 241 sample with curb.
Now the sample was put on top of the lens mount with the Americium pointing
directly at the chip.
.. figure:: https://git.sleepmap.de/audio/random241.git/plain/images/sample_over_chip.jpg
:alt: Americium 241 sample with curb over chip
Americium 241 sample with curb over chip.
You might have to improvise a little - depending on your hardware - to make
things work. |sugru| is your friend, fixing the sample over the camera chip. I
know, it looks ugly, but it certainly gets the job done!
.. figure:: https://git.sleepmap.de/audio/random241.git/plain/images/sample_fixed_over_chip.jpg
:alt: Americium 241 sample fixed over chip using sugru
Americium 241 sample fixed over chip using sugru.
I was able to place the camera in the above mentioned casing, while leading the
USB and push button switch cable out.
.. figure:: https://git.sleepmap.de/audio/random241.git/plain/images/camera_in_casing.jpg
:alt: Camera in casing
Camera in casing.
| As you can see here, I had to use two additional steel panels to complete the
casing in front and back of the box.
| The box is made from steel panels all around otherwise, but had some open
spaces in front and back (for air circulation in its previous
use-case-scenario).
| This device is now USB pluggable and on/off switchable!
TODOs:
------
- Externalization of settings for |read_gpio.py| and |random241.py|
- Further settings and advancements in sound for |random241.scd|
- Performance enhancements for |random241.py| using different search algorithm
(maybe switch to C++?)
- Detection of false positives (pixel errors) on wacky
cameras
.. |random241.scd| raw:: html
<a href="https://git.sleepmap.de/audio/random241.git/tree/SuperCollider/random241.scd" target="_blank">random241.scd</a>
.. |read_gpio.py| raw:: html
<a href="https://git.sleepmap.de/audio/random241.git/tree/remote_control/read_gpio.py" target="_blank">read_gpio.py</a>
.. |random241.py| raw:: html
<a href="https://git.sleepmap.de/audio/random241.git/tree/entropy_harvester/random241.py" target="_blank">random241.py</a>
.. |supercollider| raw:: html
<a href="https://supercollider.github.io" target="_blank">SuperCollider</a>
.. |adafruit_bbio| raw:: html
<a href="https://github.com/adafruit/adafruit-beaglebone-io-python" target="_blank">AdaFruit_BBIO</a>
.. |americium241| raw:: html
<a href="https://en.wikipedia.org/wiki/Americium" target="_blank">Americium 241</a>
.. |americium241-ionization_detectors| raw:: html
<a href="https://en.wikipedia.org/wiki/Americium#Ionization_detectors" target="_blank">ionization smoke detectors</a>
.. |github-gabriel_zoeller| raw:: html
<a href="https://github.com/fahrstuhl" target="_blank">Gabriel Zöller</a>
.. |sugru| raw:: html
<a href="https://sugru.com" target="_blank">Sugru</a>
|