Converting Feedrate and Frequency in CNC Machining with MIDI Note Numbers

In CNC machining, converting between feedrate in IPM (inches per minute) and frequency in Hz (steps per inch or inches per step) is a crucial task. One way to achieve this conversion is by using the G1 x F code for linear interpolation at a specific feedrate. However, there's more to it than just simple arithmetic.

In a future post, we'll explore the magic of MIDI note numbers and how they can be used to create musical notes on a CNC machine. But for now, let's focus on converting between feedrate and frequency.

The key to this conversion is understanding that MIDI notes can swap arbitrarily among different axes while still sounding passable. This concept is crucial in creating chords as the machine follows a 3D line through space.

Mid2cnc.py is a Python script that demonstrates how to compute a combination of distance and feedrate along an axis that will cause the stepper motor for that axis to spin at an exact frequency corresponding to a musical note. With this script, you can generate a sequence of (distance, feedrate) pairs that will produce a specific melody.

In addition to the script, this page contains audio formats, scores, and videos with visualizations of the scores during playback of the music, if available. The script has also been updated to pull proper timing from MIDI files, making it easier to use for those who are familiar with MIDI format 0 or 1.

MIDI Format 0 integrates all channels into one track, which is necessary for some keyboards. On the other hand, MIDI Format 1 separates each channel into its own track, which is the standard format used by most devices.

By using Mid2cnc.py and understanding the concept of MIDI note numbers, you can create complex musical patterns on your CNC machine. Whether you're a musician or an engineer, this technology has the potential to revolutionize the way we think about music and manufacturing.

Midi note number 33