DEVELOPER / OPEN SOURCE
16-Level Grayscale E-Paper on ESP32-S3
A technical demonstration of full-screen 16-level grayscale rendering on NOTE4 hardware, with the open-source reference project available on GitHub.
Watch on YouTube ↗ZECTRIX NOTE SERIES / DEVELOPER KIT
NOTE4Developer Kit
Build on a complete ESP32-S3 e-paper platform.
Start with a complete 4.2-inch ESP32-S3 device instead of a loose display module. Explore fast black-and-white interfaces, full-screen 16-level grayscale, custom data sources, buttons, audio, NFC, and connected workflows.
Developer edition: the first batch ships with beta demo firmware for testing and exploration. It is not the NOTE4 consumer firmware or a finished consumer software service.
LAUNCH PRICE · VALID THROUGH OCT 31, 2026
$54.99 USD$69.00 USD
Official signup on shop.zectrixlab.com. No payment is collected and joining does not reserve a unit.
NOTE4 / BLACK & WHITE E-INKDISPLAY4.2-inch black-and-white e-paper
MEMORY16 MB Flash + 8 MB PSRAM
RENDERING1-bit partial refresh + 16-level grayscale
FIRST BATCHBeta demo firmware preinstalled
WATCH / EXPLORE / BUILD
See it in action.
A growing YouTube library for rendering tests, open-source examples, firmware walkthroughs, and projects built around NOTE4 developer hardware.
PROJECT DIRECTIONS
One device. Many possible roles.
Use existing community work as a starting point, or combine the screen, controls, wireless connectivity, audio, and your own services into something more specific.
OFFICIAL DEMO01
Official EPD Demo
The official open-source reference firmware demonstrates full and partial 1-bit refresh plus full-screen 16-level grayscale on NOTE4 hardware.
View the reference codeWIKI PROJECT02
TransitInk OS
A public-transport arrival board built for NOTE4, with configurable information modules and low-power schedules.
View the Wiki projectWIKI PROJECT03
vibecoding-voice
A push-to-talk voice bridge that sends spoken instructions to Codex, Claude Code, or an active input field while returning status to the e-paper display.
View the Wiki projectWIKI PROJECT04
TRMNL Firmware
A NOTE4 client for rendered information feeds, dashboards, calendars, metrics, and other low-frequency content.
View the Wiki projectWIKI PROJECT05
Vocabulary trainer
A focused learning machine with offline word review, progress tracking, and a screen designed for sustained reading.
View the Wiki projectWIKI PROJECT06
Slate · Ink Note
An open frame and information-board stack combining device firmware, backend services, and a web management interface.
View the Wiki projectProjects, not promises
The official demo and community projects above show reusable patterns for grayscale imagery, transit boards, voice workflows, content feeds, study tools, and information frames. They can also inspire home-control hubs and other custom roles, but they are not preinstalled or officially maintained consumer features. Third-party services and additional development may be required.
FIRST BATCH / BETA DEMO
Useful on arrival.
Yours to replace.
Every first-batch unit is preloaded with a test demo so you can power on, check the display, and explore the hardware before beginning your own firmware work.
Use the preinstalled demo to check the screen, controls, and basic device behavior after unboxing.
The demo is a starting point, not a locked product layer. Move to the open reference project or your own application.
Back up what matters and keep the correct image and instructions for your hardware batch before experimenting.
First-batch starting point
01NOTE4 Devkit
02Desktop stand × 1
03Beta demo firmware
04Online development resources
TWO RENDERING PATHS
Choose speed or depth.
NOTE4 can behave like a crisp information terminal or a grayscale image surface. The two modes solve different problems, so your firmware can choose the right refresh path for each screen.
Fast black-and-white interfaces
Use full and partial 1-bit refresh for text, lists, status changes, menus, and other information that needs to update without redrawing the whole screen.
09:42PARTIAL UPDATE
12 Central Station24 Riverside · 3 min36 Airport · 11 min
UPDATED REGION1 BIT400 × 96 PX
Best suited to dashboards, control surfaces, timetables, task lists, and low-frequency UI updates.
Full-screen 16-level grayscale
Render photos, illustrations, charts, shaded icons, and richer visual compositions using the display's full-screen 4bpp grayscale path.
The reference project supports full-screen 16-level grayscale. Refresh behavior and ghosting differ from the faster 1-bit path, so test your intended update pattern.
COMPLETE HARDWARE
Hardware ready.Build your way.
The display, ESP32-S3 mainboard, battery, enclosure, buttons, audio hardware, NFC, charging circuit, and magnetic back are already integrated. Spend your time on the behavior people will actually use.
DISPLAY4.2-inch, 400 × 300
COREESP32-S3 N16R8
INPUTFront and side buttons
AUDIOMicrophone + speaker
POWER2,000+ mAh + USB-C
FORM97 × 97 × 8.75 mm
OPEN REFERENCE PROJECT
A working display path, not a black box.
The official MIT-licensed reference repository targets the black-and-white NOTE4 hardware and includes full and partial 1-bit refresh plus full-screen 4bpp grayscale. Use it to understand the display pipeline, validate your toolchain, and build outward.
NOTE4 / DISPLAY PIPELINEESP-IDF
01 init_note4_hardware(); 02 select_refresh_mode(); 03 render_framebuffer(); 04 epd_refresh(); // 1BPP FULL + PARTIAL // 4BPP FULL-SCREEN / 16 GRAY // 400 × 300 · SSD2683 build_the_rest_your_way();
Power on and validate the first-batch demo before changing the firmware.
Record the hardware batch and keep the correct images and recovery steps.
Build the reference project and test both refresh paths on your device.
Add your UI, services, data sources, and safe update workflow.
HARDWARE SPECIFICATIONS
Know the platform before you build.
The Developer Kit uses the current black-and-white NOTE4 hardware platform. Final details may vary slightly by production batch.
Display
- Panel
- 4.2-inch black-and-white e-paper
- Resolution
- 400 × 300 pixels
- Controller
- SSD2683
- Rendering
- Full and partial 1bpp refresh; full-screen 4bpp / 16-level grayscale in the reference project
Core
- Processor
- ESP32-S3, dual-core Xtensa LX7
- Memory
- 16 MB Flash + 8 MB PSRAM
- Wireless
- 2.4 GHz Wi-Fi + BLE 5.0
Controls and I/O
- Controls
- Front voice and confirm button; side function and power buttons
- Audio
- Integrated microphone and speaker
- Other hardware
- NFC, status light, and expansion interface
- Port
- USB Type-C charging and data
Power and enclosure
- Battery
- 2,000+ mAh
- Dimensions
- 97 mm × 97 mm × 8.75 mm, including magnetic back
- Material
- ABS
- Assembly
- Display, mainboard, battery, enclosure, and core peripherals assembled
Firmware and box
- First batch
- Beta demo firmware preinstalled; not the NOTE4 consumer firmware
- Reference code
- MIT-licensed NOTE4 e-paper demonstration project
- In the box
- NOTE4 Devkit and desktop stand
- Resources
- GitHub reference project and online Wiki documentation
Support boundary
- Commercial warranty
- Not offered for this development device. Hardware manufacturing defects may be eligible for support, subject to assessment and applicable law.
- Development risk
- Custom firmware, flashing, modification, incompatible accessories, misuse, and expected e-paper behavior are assessed separately and may not be covered.
CHOOSE THE RIGHT NOTE
Which NOTE4fits you?
The hardware may look related, but the promise is different. Choose by the software experience and display path you want—not by the enclosure alone.
NOTE4
Finished consumer firmware and practical default experiences. Consumer hardware specifications may differ by release version.
View NOTE4NOTE4 Devkit
Black-and-white hardware with beta demo firmware, partial refresh, grayscale experiments, and open reference code.
You are viewing this productNOTE4C Devkit
A fully assembled four-color e-paper development device for static labels, signs, cards, and occasional status updates.
View NOTE4C DevkitDEVELOPMENT DEVICE SUPPORT
A clear boundary for experimental hardware.
No commercial product warranty is offered for the NOTE4 Devkit because it is a development device. Hardware manufacturing defects may be eligible for support, subject to assessment and applicable law.
What is assessed separately
Issues caused by custom firmware, flashing, modification, misuse, incompatible accessories, or expected e-paper behavior may not be covered. Contact ZECTRIX Support before returning a device.
FAQ
Before you join the waitlist
How is the Developer Kit different from the regular NOTE4?
The Developer Kit is sold as a development device. It uses the current black-and-white hardware platform and ships with beta demo firmware, not NOTE4's finished consumer firmware or consumer software service.
What firmware is installed on the first batch?
A beta test demo is preinstalled so you can power on the unit, check the display, and begin exploring the hardware. It is a development starting point and may change between batches.
Does it support 16-level grayscale?
Yes. The open reference project supports full-screen 4bpp / 16-level grayscale as well as full and partial 1bpp black-and-white refresh. These modes have different refresh behavior, so test them against your intended use.
Does it include multilingual fonts?
Do not assume a complete multilingual font library is preinstalled. Developers choose, license, store, and render the fonts required by their own firmware within the available resources.
What is included in the box?
The box includes one NOTE4 Devkit and one desktop stand. The first batch also has beta demo firmware installed, with development resources provided online.
Can I restore the device after flashing my own firmware?
Plan recovery before flashing: identify your hardware batch, preserve the files you need, and keep the correct image and instructions. Recovery steps may differ during the beta period.
Does it include a commercial product warranty?
No. The support boundary follows NOTE4C Devkit: hardware manufacturing defects may be eligible for assessment, while problems caused by custom firmware, flashing, modification, misuse, incompatible accessories, or expected e-paper behavior may not be covered, subject to applicable law.
What is the price, and how do I register interest?
The launch price is $54.99 USD, reduced from $69.00 USD and valid through October 31, 2026—the same as NOTE4C Devkit. Use the existing ZECTRIX waitlist. Joining is free, collects no payment, and does not reserve a unit.
BUILD YOUR NOTE4
Hardware ready.Ideas open.
Join the waitlist for first-batch availability updates. Launch price: $54.99 USD through October 31, 2026. Includes the NOTE4 Devkit, one stand, and preinstalled beta demo firmware.