robby hobby

measure/measure

robby — Thu, 26 Jan 2012 10:40:22 +0000

well tempered bk. 1, c major prelude, JS Bach

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number of measures: 35

pitch presence / measure:
C: (26) C C C C C C C C C C C C C C C C C C C C C C C C C C (.74)
G: (23) G G G G G G G G G G G G G G G G G G G G G G G (.66)
D: (18) D D D D D D D D D D D D D D D D D D (.51)
E: (16) E E E E E E E E E E E E E E E E (.46)
F: (16) F F F F F F F F F F F F F F F F (.46)
A: (12) A A A A A A A A A A A A (.34)
B: (11) B B B B B B B B B B B (.31)
F#: (4) # # # # (.11)
Bb: (3) b b b (.09)
G#: (2) # # (.06)
Eb: (2) b b (.06)
C#: (1) # (.03)

order of appearance for 3+ bar sustain:
C G C C F G (E & C) G C
non-repeating: C G F E

order of appearance for 2 bar sustain, non-repeating:
C (F & D) E A B

longest sustaining tone: G (9 bars), second: C (5 bars)

chords that follow a measure of C major:
C D F A (D major 7)
C E A (A minor)
C E F A (F major 7)
C E G Bb (C7)
C D F G (2x)

chords that preface a measure of C major:
D F G B (G major 7) (3x)
D F G# B
C D# F# G A

Minimoog OSC OCT

robby — Tue, 10 Jan 2012 11:38:43 +0000

How to tune a Minimoog when the scale (OSC OCT) won’t stretch as far as you need:

Underneath the case, at the top left corner, notice the orange-orange-orange resistor. This is what we added to fix the issue, it runs in series with the OSC OCT pot.

After tuning the scale of the keyboard as close as it could go, with the schematic and a voltmeter, we could establish the OSC OCT pot was at its highest Ω without removing it from the board. We needed Ω to be higher, so the new resistor added in series raises the total Ω = 33k + potentiometer. You have to make sure to break the connection that travels underneath the new resistor or nothing will happen. Notice the tiny scratch.

Do it in this order:
1: set the OSC OCT pot a nice spot somewhere in the middle
2: scratch the conducting material away where you see the added 33k resistor.
3: bridge the newly scratched gap with a resistor, try out different values until your high notes are within range.

fractal

robby — Fri, 15 Apr 2011 00:48:32 +0000

blanket fort

robby — Sun, 20 Mar 2011 06:19:46 +0000

1V, 2V, 4V geodesic domes

polar coordinate rhythm + orthographic projections

robby — Sun, 10 Oct 2010 20:39:04 +0000

click to activate : arrow keys to rotate : space bar to play

full screen

future fossil fuel

robby — Fri, 13 Aug 2010 02:43:57 +0000

Touch a magnet to the bolt and the LED will flash. If you add a capacitor+resistor, the flash slows down and the light gently fades out.

the generator only works on one pole of the magnet. You can attach to the non-working pole then pull the magnet apart fast, the generator flashes here too.

Now the generator can capture all approaching/departing electricity from each pole. If the generator nears one pole, departs it for the other, then depart that one, we generate 4x the electricity

PDF instructions to build a bike light generator and light out of recycled parts.