4.2 inch Photo Board: Difference between revisions
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== <span style="color: rgb(52, 176, 176);">Q4:Screen doesn't update after upload?</span> == | == <span style="color: rgb(52, 176, 176);">Q4:Screen doesn't update after upload?</span> == | ||
A full E-Paper refresh takes ~21 s — that's normal. If nothing changes after 30 s, press RST to reboot. | A full E-Paper refresh takes ~21 s — that's normal. If nothing changes after 30 s, press RST to reboot. | ||
|dl1Type=Demo | |||
|dl1Name=A32 Photo 4 2 v1.0.zip | |||
|dl1File=A32 Photo 4 2 v1.0.zip | |||
|dl2Type=Document | |||
|dl2Name=4.2inch Photo Board 4C UserManual EN v1.0.pdf | |||
|dl2File=4.2inch Photo Board 4C UserManual EN v1.0.pdf | |||
|dl3Type=Document | |||
|dl3Name=4.2inch Photo Board 4C UserManual RU v1.0.pdf | |||
|dl3File=4.2inch Photo Board 4C UserManual RU v1.0.pdf | |||
|displayMode={{{displayMode|详情}}} | |displayMode={{{displayMode|详情}}} | ||
|cardPage={{{cardPage|{{PAGENAME}}}}} | |cardPage={{{cardPage|{{PAGENAME}}}}} | ||
Revision as of 16:50, 9 September 2026
Introduction
1.The 4.2 inch Photo Board(4C) is an open-source 4-color E-Paper development board based on the ESP32-WROOM-32E MCU. It carries an onboard 4.2-inch black / white / red / yellow E-Paper display at 400×300 resolution, suitable for desktop photo frames,dynamic labels, low-power information displays, and similar applications.
2. Designed for makers, educators, and secondary developers, the board integrates a USB-C port, CH340C USB-to-serial bridge, TF card slot, three physical buttons, dual I/O expansion headers, plus the BOOT and RST buttons — flashing and debugging require no extra tools.
3. The companion sketch is built on the Arduino framework and provides a full photo-album manager plus a web configuration UI: upload an image through the browser and the board displays it. Auto-switching follows a configurable timer, with TF card mirror backup and one-click clear-all.
Specifications
| MCU | ESP32-WROOM-32E, 240 MHz dual-core, integrated Wi-Fi 4 + BLE. |
|---|---|
| Display | 4.2-inch 4-color E-Paper (black / white / red / yellow), 400×300 resolution,FPC-24P interface, no backlight, easy on the eyes.
|
| Storage | Internal LittleFS (~1 MB available) as primary album storage; TF card can serve as a mirror backup.
|
| Buttons | Previous / Mode / Next three-button control for manual page change and mode switch.
|
| Indicators | Red PWR power LED + blue USR user LED. |
| Interfaces | USB-C (power + data / flashing), TF card slot, P3/P5 and P1 dual-row I/O expansion pins
|
| Wireless | Defaults to AP mode hotspot (SSID: ePaperDisplay); can be switched to STA mode to join a home router
|
| Open source | Schematics, firmware source code and Web UI are all open;secondary development is supported
|
Hardware
1.1 Connect Power
Use a standard USB-C data cable to connect the board to a computer or charger. On power-up the screen shows the 4-color hint image.
1.2 Connect to the Board
The board starts Wi-Fi in AP mode by default:
SSID: ePaperDisplay
Password: 88888888
After connecting a phone or computer to this hotspot, open the browser at http://192.168.4.1 to enter the configuration page.
1.3 Switch to STA Mode
To make the board join your home router directly, fill in the SSID and password under the Settings card of the Web UI and save. The board reboots and joins the router in STA mode. Open the browser at the IP it obtained from the router to access it on your local network (recommended for advanced users).
1.4 Upload Your First Photo
(1). Open http://192.168.4.1 (AP mode) or the board's LAN IP.
(2). In the Upload card click Choose File and pick a JPG / PNG image from your computer (recommended aspect ratio ≈ 4:3).
(3). The browser quantizes the image locally into a 400×300 4-color image (black / white / red / yellow) and shows a live preview.
(4). Click Upload; once upload finishes, the screen refreshes within ~21 seconds.
Size


FAQ
Q1:Screen shows nothing after flashing?
Check that the FPC 24P cable is firmly seated and oriented correctly (typically metal side up); make sure the supply is stable (recommend a 5 V / 1 A or better USB-C source).
Q2:Cannot find the USB-SERIAL CH340 port?
Try a different data cable (some cheap cables only charge); install the CH340 driver manually under Windows; hold BOOT while powering on to force the ESP32 into download mode.
Q3:Web page won't open (192.168.4.1 no response)?
Confirm the phone / computer has joined the board's AP hotspot (SSID: ePaperDisplay).Some phones conflict with mobile data — temporarily disable mobile data, or wait a few seconds after connecting.
Q4:Screen doesn't update after upload?
A full E-Paper refresh takes ~21 s — that's normal. If nothing changes after 30 s, press RST to reboot.
Downloads

