OLMO

Optical Laser Midi Operator

      

The Story of OLMO

Until the beginning of 2020, I was the proud bass player of a band called Flashback. Unfortunately, after a long break due to the COVID-19 situation, our beloved drummer Olmo decided to leave the band and pursue a different musical adventure.

Finding a new drummer is always challenging, and drummers have the disadvantage of not having a volume knob. Therefore, I decided to seek a different solution to our drummer issue—one that is always on time, has a volume knob, and preferably goes by the name Olmo.

This led to the creation of OLMO: The Optical Laser MIDI Operator.

As far as I know, OLMO is a unique piece of equipment that nobody else has created so far.

The Idea

The initial concept behind this machine was to create a laser harp—an instrument where interrupting lasers play notes, akin to a harp. However, many variations of laser harps already exist, and I didn’t want to replicate an existing design.

In a moment of inspiration, I realized I could instead develop an automated laser interrupter machine, akin to a barrel organ with a punch card. However, punch cards pose challenges with swapping during playback, and a continuously repeating sequence might become monotonous.

The solution was to utilize a flat, round, transparent medium suitable for lasers—a homage to the Compact Disc. The CD, stripped of its aluminum coating and affixed with a vinyl sticker, is divided into 32 equal boxes across two tracks. The rhythmic pattern is created by adhering precut stickers to the CD in a specific sequence.

Technical Details

This machine falls into the category of a sequencer, playing a repetitive sequence of notes. Each track features a red laser directed at a phototransistor sensitive to red light. When a black sticker interrupts the laser, it is detected by an Arduino Pro Micro[1]. The BPM (beats per minute) can be adjusted by varying the stepper motor speed. All CDs are synchronized perfectly via a shared belt drive and small wedges on each CD.

[1] The Arduino Pro Micro utilizes the ATmega32U4 processor, featuring a native USB port for programming and MIDI communication via a single USB connection. This makes it highly suitable for MIDI projects.

Available Features

Internal Clock Mode: The module generates its own MIDI clock, adjustable using the ‘+’ and ‘-‘ buttons. The BPM is calculated and displayed on the 4-digit display.

External Clock Mode: This mode allows synchronization with software like Ableton. CDs start and stop rotating by pressing play/pause on your computer, automatically syncing via a synchronized CD (encoder). This feature enables the instrument to be used live.

Manual Sync: In manual sync mode, BPM is determined by an external clock, but the offset can be adjusted manually. This allows syncing with devices that output MIDI clock, such as synthesizers or digital turntables like Traktor.

Switch Notes and Preview: Pressing the ‘<‘ button activates NOTE change mode. Each channel’s note can be switched by toggling the switch up or down. Using two MIDI channels, the current or desired note for each track can be previewed through headphones before enabling it on the audio output.

Future Ideas

To create beats longer than 4 quarters, multiple tracks will be necessary. I plan to add a sequencer/recording function to toggle lasers on and off in a recurring sequence.

Analog time!

 

In this video, OLMO is directly connected to a Vermona DRM1 analog drum computer via MIDI.

By setting OLMO to internal clock and manual sync, the device can operate independently of a computer. What’s particularly exciting about this setup is that OLMO can manipulate the sequence while the Vermona, featuring 8 analog drum synths and 7 effect knobs each, shapes the sound.

When used with other synthesizers, OLMO should be set to external clock and auto sync, connecting it digitally through USB or in a MIDI chain for seamless synchronization.

As evidenced by the dust on OLMO, it had not been used for a while, marking just the beginning of exploring its potential in tandem with the Vermona. Nonetheless, this provides a promising introduction to the capabilities of these devices together.

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