Pet Rock

A EuroPi clone of Johan Senzel’s Pet Rock.

This script generates pseudo-random gate sequences based on the phase of the moon.

I/O Assignments

din: external clock input for sequence A
ain: external clock input for sequence B
b1: manually advance sequence A
b2: manually advance sequence B
k1: speed control for sequence A
k2: speed control for sequence B
cv1: primary gate output for sequence A
cv2: inverted gate output for sequence A
cv3: end of sequence trigger for sequence A
cv4: primary gate output for sequence B
cv5: inverted gate output for sequence B
cv6: end of sequence trigger for sequence B

Both sequence A and sequence B can be internally clocked by setting the speed using K1 and K2. Turning these knobs fully anticlockwise will stop the internal clocks.

Configuration

Pet Rock can be configured to use different pseudo-random rhythm-generating algorithms. To choose, edit config/PetRock.json to set the MOODS key:

{
    "MOODS": "classic"
}

MOODS can be one of classic (default), alternate, or all

Depending on the MOODS configured, the following algorithms are used, cycling every new moon:

Classic

Plain
Reich
Sparse
Vari

Alternate

These algorithms were implemented in the original Pet Rock firmware, but ultimately not used in the final release.

Blocks
Culture
Over
Wonk

All

When "all" moods are selected, the order is the 4 classic algorithms, followed by the 4 alternate algorithms, in the order listed above.

Note on suits

Yes, I’m aware that “shields” isn’t a normal Tarot suit. Originally I used “clubs” (an alternative to the traditional “wands” suit in most tarot decks). But it seemed weird having 3/4 English card suits used for the alternate moods, and then have “shields” tossed-in to fill it out; “shields” is a suit more associated with Swiss playing cards.

Since shields and swords are a natural pairing, I swapped things around to have, in my mind, more logical groupings. I’m sorry if this decision causes anyone distress.

Additionally, I realize the “pentacle” symbol has some negative associations for some. No offense is meant; this is a traditional suit in tarot cards, and felt appropriate for a moon-phase-tracking program. I did consider swapping it for its “coins” alternative, but was concerned that a circular or elliptical coin motif might be too visually similar to the full & gibbous moon icons.

Required Hardware

This script requires a Realtime Clock (RTC) to EuroPi’s secondary I2C header pins, located on the underside of the board.

See Realtime Clock Installation for instructions on installing and configuring the realtime clock.