CD4017 Decade Sequencer

CD4017 Decade Sequencer (2018)

Built around the CD4017 decade counter, this sequencer outputs a programmable voltage (0-9V) per step for up to 10 steps. It was built specifically to modulate the frequency of an old Tektronix function generator. However, it is capable of modulating a wide range of old test equipment, guitar pedals, synthesizer modules, or whatever may benefit from a varying voltage with respect to time. The length of the sequence is programmable and each step can be muted. Additionally, it has a tactile reset and step hold button.

The sequencer uses a standalone 555 timer circuit enclosed in fabric (shown below) as a clock. But, the sequencer is clockable via any 0-5V signal.

A passive speaker in a wearable pouch with a volume knob is used to make the function generator audible.

The entire sequencer system can be powered by a single 9V battery.

Originally, I intended to fit the whole system—and a small VCO circuit—in a helmet. But, I wanted to bring something to the New England Synth Meet, which was a week from when I started building. Because of the time crunch and the bulkiness of the hardware, I resorted to a quasi-wearable set of soft and found-object enclosures.

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MEDIA:
Recordings of guitar through an EHX Pitch Fork, modulated by the decade sequencer.
♪ decade-seq-pf-seq1.mp3
♪ decade-seq-pf-held.mp3
♪ decade-seq-pf-seq2.mp3
♪ decade-seq-pf-fast.mp3