Capacitive touch sensing usually means some combination of soldering, pull-up resistors, and debugging why a sensor reads noisy. The latest episode of Adafruit’s CircuitPython Parsec series, published October 30 and hosted as always by John Park, demonstrates a version of touch sensing that skips most of that: cap touch wired entirely through STEMMA ports, Adafruit’s keyed, solder-free connector standard, running on a PyPortal.
What the episode actually covers
The segment is built around plug-and-play capacitive touch sensing — connect a STEMMA cable, run the provided code example, and the touch input works without any breadboarding or soldering. Park also demonstrates a bonus ground-reference wire technique, a small but genuinely useful detail for anyone who’s dealt with capacitive sensing’s sensitivity to floating or inconsistent grounding, which is one of the more common sources of flaky touch readings in DIY builds.
The code for this specific segment lives in the series’ GitHub repo, timestamped to the episode’s own date (2026-10-29/code.py), alongside links to CircuitPython’s own site and the PyPortal product page it was demonstrated on.
A series worth knowing about if you don’t already
This is one episode in a series that’s been running on Adafruit’s blog for years — the repo’s commit history runs back through 2024 and 2023, with a new segment landing almost every week, covering a rotating set of CircuitPython sensing and interface techniques. For anyone doing recurring CircuitPython work on installations or wearables, it’s accumulated into one of the more comprehensive, bite-sized references available: each episode tackles one specific technique (this one is cap touch over STEMMA) rather than a sprawling general tutorial, which makes individual episodes easy to search for and reuse later.
Why STEMMA-based touch sensing matters for interface design specifically
The appeal here isn’t that capacitive touch is new — it’s that STEMMA removes the single biggest barrier to iterating on touch-based interfaces quickly: wiring. A solder-free, keyed connector means a touch sensor can be swapped, repositioned, or added to a project in the time it takes to unplug and replug a cable, rather than requiring a breadboard rebuild or a fresh soldering pass. For anyone prototyping interactive objects, wearables, or installation inputs where the physical placement of touch points is still being worked out, that iteration speed is worth more than it might sound.
Adafruit’s own episode video, with the live code example.
Related Reading
- CircuitPython Parsec code repository — GitHub
- CircuitPython — official site
- The Twelve Lines That Stop Your Installation Dying When a Sensor Falls Off — our coverage of an earlier CircuitPython Parsec episode
- Capacitive Touch: Getting Started With the MPR121 — our tutorial on a different capacitive-touch approach