A builder constructed a DIY galvanic hair electrolysis machine using an RP2040, a Dickson charge pump, a 5-bit resistor DAC, and a 3D-printed electrolysis pen.
Key Takeaways
Galvanic electrolysis is the only FDA-recognized permanent hair removal method; it generates lye (NaOH) in the follicle via DC current through a needle electrode.
Lye units (LU) = mA x seconds x 10; target ranges from 10 LU (fine vellus hair) to 60 LU (very deep terminal hair), pulled from a 2001 medical textbook.
The Dickson charge pump boosts 3.3 V I/O to ~12 V using RP2040 PWM; small capacitors and slow switching cap output at a few mA, acting as a hardware safety limit.
Current control uses a 5-bit resistor DAC driving an op-amp and BJT; the RP2040 ADC reads the sense resistor to verify actual vs. requested current for accurate LU tracking.
Polarity matters critically: reversed leads generate HCl instead of NaOH in the follicle, significantly increasing scarring risk.
Hacker News Comment Review
Discussion skews strongly enthusiastic and replication-focused; multiple commenters expressed intent to build their own or asked for direct help sourcing parts and technique.
Several commenters flagged real unanswered questions: hardware cost, pain scaling across body areas, depth-detection feedback, and long-term efficacy of early test follicles.
Notable Comments
@goodmythical: Raises the most substantive gap list: cost, pain comparison to commercial units, depth sensation cues, and whether results from early arm tests have held.
