[Jeremy Bell] loves scratching, but he had a problem. His Hercules DJ controller wasn’t really doing a great job at emulating the kind of action one would get with a real turntable. The solution was both mechanical and electronic in nature!

As stock, the Hercules MIDI rig lets you scratch in a relatively simplistic way. When it detects a finger touching the rotary control, it lets you scratch back and forth with great motion tracking. However, when you let go, playback resumes at regular speed instantaneously, which creates a somewhat inorganic sound.

The fix was to make some mechanical mods to the MIDI controller. [Jeremy] tried out a variety of different methods of using a motor to spin the rotary control continuously, from geared rigs to belt-driven setups. It was then possible to scratch on the controller, and then let it return to normal rotational speed, creating much smoother  auditory transitions. However, this was imperfect, as for whatever reason, the Hercules rig would stop tracking the rotary control accurately unless it detected a finger was touching it. [Jeremy] worked around this by whipping up a slip-ring-like setup to keep his body permanently in contact with the rotary control even while spinning.

The results are pretty great—they’re both mechanically janky and fantastically satisfying to listen to. We’ve featured some other great DJ controller hacks over the years, like this sweet Pioneer UI upgrade.