Signal & Solder · 28 August 2026

XIAO nRF54 Sense, NFC wake taps, and ESP32‑P4 HMI kits (Aug 21, 2026)

🔧 Tool of the Week

Seeed XIAO nRF54LM20A (Sense) A tiny, ultra‑low‑power multiprotocol XIAO with Nordic’s nRF54LM20A (BLE 6.0, Matter/Thread, NFC), useful for battery sensors, TinyML wake‑up patterns, and Matter testbeds. Great if you need lots of wireless options in a thumb‑sized board. 🔗 Seeed: Meet XIAO nRF54LM20A (Sense)

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🛒 Deals & Finds

  • Adafruit ST25DV16K I2C NFC/RFID EEPROM breakout

– Cheap, reprogrammable NFC tag you can drive over I2C (perfect for wake/tap workflows). 🔗 Adafruit product page

  • TiltForge — Matter-native blind‑tilt retrofit (preorder)

– Repairable, head‑rail retrofit for blinds that ships as kits or assembled units; good if you build open, repairable home automation. 🔗 TiltForge

  • Waveshare ESP32‑P4 / WiFi6 Touch LCD HMI boards

– Low-cost HMI dev boards (ESP32‑P4 + C6 combos) for responsive displays, camera and audio demos. Nice for prototyping embedded UIs. 🔗 Waveshare ESP32 P4 / WiFi6 dev boards

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🧪 Cool Build

Harvesting NFC Energy to Transmit Commands A practical demo that harvests a phone’s NFC RF field (ST25DV family) to write a command and wake a Pico — zero standby power for the listener. Useful pattern for battery‑free wake/tap interactions and ePaper signage. 🔗 Hackaday.io project

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📚 Worth Reading

  • Congratulations To The Green Powered Challenge Winners – Short roundup and winners; good source of low‑power ideas and practical energy‑harvesting demos. 🔗 Hackaday: Green Powered winners
  • Python on Microcontrollers: MicroPython & CircuitPython roundup – Weekly-ish roundup with practical board mentions (includes new small XIAO boards and tiny BLE devices). Good for MicroPython/CircuitPython builders. 🔗 Adafruit daily newsletter (Python on Microcontrollers)

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⚡ Quick Hits

  • esptool releases & notes — still the go‑to flasher/CLI for Espressif boards. 🔗 espressif/esptool releases
  • ForgeUI / esp32p4 UI studio (LVGL drag‑and‑drop) — fast path to HMI exports for Waveshare ESP32‑P4 boards. 🔗 esp32p4-ui-studio (GitHub)
  • ESPHome 2026 updates — faster builds and toolchain improvements (helpful for frequent firmware iterations). 🔗 ESPHome changelog (Aug 2026)

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📺 Cool Videos

  • inki — NFC: HelloWorld :-) !

– Short demo: phone tap → write/display on ePaper; shows the energy‑harvesting / NFC trick in action. 🔗 YouTube: inki NFC demo

  • ESP32‑P4 First Look! This Thing is a Beast!

– Hands‑on demo of Waveshare ESP32‑P4 dev kits and what they make possible for displays/camera/H.264. 🔗 YouTube: ESP32‑P4 First Look

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