# ZecTrix Note 4 – A 4.2-inch ESP32-S3 wireless e-paper display for voice tasks

> Source: <https://www.cnx-software.com/2026/08/05/zectrix-note-4-a-4-2-inch-esp32-s3-wireless-e-paper-display-for-voice-tasks/>
> Published: 2026-08-05 04:57:59+00:00

Designed by ZecTrix Lab in China, the Note 4 is an ESP32-S3-based AI smart note with a 4.2-inch e-paper display and built-in voice input. The device is designed to display reminders, notes, clocks, weather, images, and custom templates, while the Note 4C variant replaces the monochrome display with a four-color e-paper panel. The device features 2.4GHz Wi-Fi and Bluetooth 5.0 connectivity, a microphone, a speaker, NFC, physical buttons, a USB Type-C port, a 2,000mAh rechargeable battery, and GPIO expansion for custom hardware projects. ZecTrix Note 4 / Note 4C specifications: SoC – Espressif Systems ESP32-S3 CPU – Dual-core Tensilica LX7 up to 240 MHz with vector extension for AI/ML workloads RAM – 512KB SRAM; 8MB PSRAM Wireless – WiFi 4 and Bluetooth LE 5 Storage – 16MB flash Display Note 4 – 4.2-inch monochrome E-Ink display, 400 × 300 resolution; supports partial refresh Note 4C – 4.2-inch four-color (BWRY) E-Ink display, [...]

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