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

Materials

Americium 241

If you're living in the US, you might still have an ionization smoke detectors around. For (mostly) everyone else, there's the possibility of ordering Americium on ebay!

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 Gabriel Zöller wanted to get rid of his and it was broken in just a beautiful and fitting way (with the lens already removed):

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:

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:

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.

Americium 241 sample with curb.

Now the sample was put on top of the lens mount with the Americium pointing directly at the 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!

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.

Camera in casing.