The Arturia KeyStep is a small MIDI keyboard with a set of buttons that allow you to shift the octave up or down. These buttons blink when the octave is currently shifted, with faster blinking meaning more of a shift. Daniel S. Gruss looks into the issues:

Why is that is a problem? First of all, it’s hard to convey in video form how bright these LEDs are. Worst of all, the rate of flashing isn’t connected to anything musical, which means the sequencer can be set a certain tempo and the octave buttons will happily continue flashing to their own beat (which appears to be a subdivision of a second). Which causes the lights above.

 

It’s like when two car alarms are going off and they just. can’t. get. in. time. Except now it’s flashing lights in your face while trying to make music. I’m probably just too closed-minded to be able to achieve this polyrhythmic enlightenment, but I’m not the only one who has had an issue. Luckily, we can put off getting better at music by tackling this mundane issue in depth!

The post looks in-depth at reverse engineering the device. The microcontroller is a STM32F103 and VCT6, which is an ARM 32-bit Cortex-M3 CPU. And this appears to be the “LQFP100” package version. Each firmware version is hosted on Arturia’s Website as a “.led” file.

Check out the details in the post here.