Sequencer projects on a small microcontroller usually hit a wall fast, since there are only so many connections to go around. This build tackles that head on. The maker put together an eight-step sequencer driven by pulse width modulation, using a 4051 chip to reach the full eight steps. To me that seems a clever way to lengthen a pattern without piling on extra hardware.
Everything sits on a solderless breadboard. A row of eight blue square trim potentiometers runs across it, and a microcontroller board with a red status LED is connected through a USB cable. Jumper wires link the board to the power rails. The build also includes three VC out plugs and a VC in.
The detail that stands out for me is the tempo control the maker added through a knob. While the sequence plays, the trim potentiometers get adjusted with a small metal adjustment tool, and turning those dials shifts the melody's pitch across the stepped sequence. The maker says it sounds really good for an Arduino, and the circuit plays a looping electronic melody of synthesized tones.
Two things leave me curious. The code is based on another maker's project, and that original has only been shared as a link rather than named in full. On top of that, the maker has mentioned that a second 4051 would double the pattern to sixteen steps and has offered to pass along the mods. I would genuinely like to see that expanded version built.