ESP32-S3-WROOM-1
Pocket AI E-Ink Reader
Aperçu
A low-cost, simple pocket-size 4-5 inch e-ink e-reader with built-in 4G/LTE for occasional cloud LLM Q&A and USB-C rechargeable battery power.
Eddie SamuelsArchitecture système
POWER
MODULE
MCU
DISPLAY
SENSOR
- USB_C → POWERUSBUSB-C provides 5V input for battery charging and optional USB data routing for programming/debug
- BATTERY → POWERPowerSingle-cell Li-Ion battery connects to charger and system power-path
- POWER → MCUPowerRegulated 3.3V rail powers the main MCU
- POWER → DISPLAYPower3.3V supply for e-ink display logic
- POWER → TOUCHPower3.3V supply for touch controller
- POWER → STORAGEPower3.3V supply for microSD socket/card
- POWER → FUEL_GAUGEPower3.3V supply for battery fuel gauge
- POWER → CELLULARPowerDedicated modem supply rail derived from battery/power-path for cellular transmission peaks
- MCU → DISPLAYSPIMCU controls e-ink display over SPI with extra control/status pins
- MCU → TOUCHI2CMCU reads touch coordinates and controls touch controller reset
- MCU → CELLULARUARTAT command and data communication between MCU and LTE modem
- CELLULAR → SIM_CARDGPIOCellular modem interfaces directly with Nano SIM card
- CELLULAR → ANTENNA_LTEGPIORF connection from cellular modem to LTE antenna
- MCU → STORAGESPISPI interface to removable microSD storage
- MCU → FUEL_GAUGEI2CMCU reads battery state-of-charge and low-battery alerts
- BATTERY → FUEL_GAUGEADCFuel gauge monitors battery voltage directly
Nomenclature
| Référence | Type | Composant | Fabricant | Boîtier | Qté | Fiche technique | Correspondance |
|---|---|---|---|---|---|---|---|
| BQ24074RGTR | POWER | BQ24074 USB-C Li-Ion Charger and Power-Path + TPS62740 Buck Converter Handles USB-C 5V input, single-cell Li-Ion battery charging, power-path management, and efficient 3.3V system rail generation for long battery life | Texas Instruments | VSON-16 | 1 | Correspondant | |
| 88-569747-35E | POWER | Single-cell Li-Ion Battery 3.7V Portable energy storage for long battery life operation | Amphenol Aerospace | — | 1 | Correspondant | |
| USB-101 | MODULE | USB Type-C Receptacle Provides 5V charging input and optional USB data/programming connection | HOOYA | USB Type-A | 1 | Correspondant | |
| ESP32-S3-WROOM-1-N4R8 | MCU | ESP32-S3-WROOM-1 Main controller for UI, e-book rendering, e-ink display control, local storage access, power management, and cellular modem communication for cloud LLM access | Espressif Systems | 41-SMD Module | 1 | Correspondant | |
| 4.2inch e-Paper Module | DISPLAY | 4.26-inch E-Ink Display 480x800 with SSD1683-compatible driver Main ultra-low-power reading display for books, articles, and AI responses | Waveshare | - | 1 | Correspondant | |
| TOUCH-01 | SENSOR | GT911 Capacitive Touch Controller Provides touch input for page navigation, menus, and LLM interaction | OSEPP Electronics LTD | — | 1 | Correspondant | |
| SIM7080G | MODULE | SIM7080G LTE Cat-M/NB-IoT/GNSS Module Provides low-power cellular connectivity for cloud LLM access and data synchronization | SIMCom Wireless Solutions Limited | 77-SMD Module | 1 | Correspondant | |
| NANO-SIM-501A | MODULE | Nano SIM Socket Holds SIM card for cellular network access | Dongguan Yuandi Electronics Co., Ltd. | SMD | 1 | Correspondant | |
| LTE ANTENNA KIT | MODULE | LTE Main Antenna RF antenna for cellular network communication | Pycom Ltd. | — | 1 | Correspondant | |
| MICROSD-PI | MODULE | microSD Card Socket Removable storage for books, articles, fonts, and cached AI content | Gravitech | — | 1 | Correspondant | |
| Li-ion Battery HAT | SENSOR | MAX17048 Li-Ion Fuel Gauge Monitors battery voltage and state-of-charge for user battery indication and low-power management | Waveshare | - | 1 | Correspondant |
Guide de fabrication
18-28 hoursAdvanced
1
Procurement & Preparation
- Order all primary modules and verify each received part number matches the build list before assembly: BQ24074RGTR charger IC, TPS62740 buck converter section parts, 88-569747-35E single-cell Li-Ion battery, USB-101 USB Type-C receptacle, ESP32-S3-WROOM-1-N4R8 module, 4.2inch e-Paper Module, TOUCH-01 GT911 touch board, SIM7080G modem, NANO-SIM-501A socket, LTE ANTENNA KIT, MICROSD-PI socket, and MAX17048 fuel gauge hardware.
- Prepare or source the main PCB designed around the listed connections: USB-C to BQ24074 power path, battery to charger and MAX17048, TPS62740 3.3V rail for ESP32-S3-WROOM-1-N4R8, e-ink, GT911, microSD, and MAX17048, plus a separate VSYS_3V8 rail for SIM7080G.
- Gather the passive support parts required for stable operation: USB-C CC resistors for 5V sink mode, charger programming resistors, buck converter inductor and capacitors, SIM7080G bulk capacitors near VBAT input, SPI and I2C pull-ups where needed, ESD protection for USB and SIM lines, and battery connector or welded leads matching the 88-569747-35E cell.
- Inspect the 4.2inch e-Paper Module flex, the TOUCH-01 sensor, the NANO-SIM-501A socket pins, and the MICROSD-PI socket for bent contacts or shipping damage, then dry-fit each part on the PCB or mechanical frame to confirm pocket-size layout clearance.
- Set up the firmware toolchain on a workstation by installing ESP-IDF for the ESP32-S3-WROOM-1-N4R8, USB serial drivers for programming over USB-C, a serial terminal for AT command testing, and the libraries needed for SSD1683-compatible e-ink driving, GT911 touch, microSD storage, MAX17048 battery reporting, and SIM7080G control.
2
Hardware Assembly & Wiring
- Solder the USB-101 USB Type-C receptacle, BQ24074RGTR charger section, and TPS62740 buck converter section onto the PCB, then wire VBUS and GND from USB-C to the charger, connect the battery input pads, and route the regulated 3V3 output to the ESP32-S3-WROOM-1-N4R8, e-ink display, GT911 touch controller, microSD socket, and MAX17048.
- Install the 88-569747-35E Li-Ion battery and connect VBAT and GND to the charger and fuel gauge path, then mount the MAX17048 circuit so BAT_SENSE monitors the battery directly while SDA, SCL, and ALERT are routed back to the ESP32-S3-WROOM-1-N4R8.
- Solder the ESP32-S3-WROOM-1-N4R8 onto the main board and connect its SPI lines to the 4.2inch e-Paper Module using MOSI, SCLK, CS, DC, RST, and BUSY, with trace lengths kept short and a solid ground reference for stable screen refresh.
- Mount the TOUCH-01 GT911 touch controller and wire SDA, SCL, INT, and RST to the ESP32-S3-WROOM-1-N4R8 I2C and GPIO pins, then align the touch panel over the 4.2inch e-Paper Module so the active area fully covers the visible reading region.
- Install the SIM7080G modem, provide its VSYS_3V8 supply from the power section, connect UART TX, RX, RTS, CTS, plus PWRKEY and STATUS lines to the ESP32-S3-WROOM-1-N4R8, then solder the NANO-SIM-501A socket to the SIM7080G SIM interface and connect the LTE ANTENNA KIT to the modem RF port with the shortest practical feed path.
- Solder the MICROSD-PI socket and wire its MOSI, MISO, SCLK, and CS lines to the ESP32-S3-WROOM-1-N4R8 SPI bus, using either a dedicated chip-select or a shared SPI bus with separate CS from the e-ink display, then verify card insertion and retention.
- Complete the mechanical assembly by fixing the PCB, battery, display, touch stack, SIM socket access, USB-C port, and microSD opening into a slim pocket-size enclosure, leaving an RF-safe area for the LTE ANTENNA KIT and enough ventilation for charging.
3
Firmware Setup
- Connect the assembled board to a computer over the USB-101 port and flash a bootloader and main firmware to the ESP32-S3-WROOM-1-N4R8 using ESP-IDF, enabling USB or UART download mode as required by the board design.
- Configure the firmware GPIO map to match the actual wiring for the e-ink SPI interface, GT911 I2C lines, SIM7080G UART handshaking and PWRKEY control, microSD SPI chip-select, and MAX17048 I2C address and ALERT pin.
- Load the SSD1683-compatible display driver and render a startup UI optimized for 480x800 portrait reading, including book list, battery icon from MAX17048, LTE signal indicator from SIM7080G status, and a simple English text entry or prompt selection screen for cloud LLM questions.
- Initialize the TOUCH-01 GT911 firmware support, set the screen coordinate mapping to the physical display orientation, and implement touch actions for page turn, menu open, network connect, and sending a short LLM question over the cellular link.
- Configure the SIM7080G with AT commands for the selected carrier APN, PDP context, and low-power operation, then add firmware routines to open a secure cloud API connection, upload compact English prompts, and cache returned LLM responses on the MICROSD-PI card for offline review.
- Enable power management features in firmware: deep sleep on idle, wake on touch or modem status as needed, reduced e-ink refresh frequency, battery percentage readout from MAX17048, and safe low-battery shutdown thresholds to protect the 88-569747-35E cell.
4
Testing & Calibration
- With no battery connected initially, apply 5V through the USB-101 port and verify charger input, battery charge regulation, 3V3 rail from the TPS62740 section, and VSYS_3V8 for SIM7080G using a multimeter and oscilloscope, then repeat with the 88-569747-35E battery attached.
- Run a display and touch diagnostic by drawing full black, full white, and grayscale test patterns on the 4.2inch e-Paper Module, then calibrate the TOUCH-01 GT911 touch points for the four corners and center so page controls and menus align correctly.
- Insert a provisioned Nano SIM into the NANO-SIM-501A socket, attach the LTE ANTENNA KIT, and test SIM7080G registration, RSSI reporting, packet data attach, and a live cloud LLM query that returns a short English response displayed on the e-ink screen and saved to the microSD card.
- Test removable storage by loading EPUB, TXT, or cached article files onto a microSD card, confirming the ESP32-S3-WROOM-1-N4R8 can mount the card, enumerate directories, open books, render pages to the e-ink display, and recover gracefully if the card is removed or corrupted.
- Measure battery life in realistic use by alternating reading sessions, occasional touch interaction, and brief LLM requests over LTE, then tune modem sleep timing, display refresh policy, and CPU frequency until the device reaches the intended low-cost portable reader behavior with stable charging and acceptable standby time.
Document
mini e-ink e-reader with LLM access
A low-cost, simple pocket-size 4-5 inch e-ink e-reader with built-in 4G/LTE for occasional cloud LLM Q&A and USB-C rechargeable battery power.
Design Overview
| Item | Details |
|---|---|
| Product Type | mini e-ink e-reader with LLM access |
| Key Functions | Read books and articles on an e-ink display, Occasional AI question answering via LLM, Cellular connectivity for cloud LLM access, Long battery life for portable reading, USB-C rechargeable operation |
| Power Source | USB-C 5V / Li-Ion Battery |
| Connectivity | 4G/LTE |
| Size | pocket-size mini device with 4-5 inch screen |
| Environment | indoor |
| Difficulty | Advanced |
| Est. Time | 18-28 hours |
System Architecture
Power Topology: USB-C 5V enters the BQ24074 charger/power-path IC, which charges the single-cell Li-Ion battery and powers the system simultaneously. A high-efficiency TPS62740 buck converter generates the main 3.3V rail for ESP32-S3, e-ink display, touch controller, microSD, and fuel gauge. The cellular modem is powered from a dedicated approximately 3.8V system/battery rail sized for LTE current bursts. The MCU can place the display and modem into low-power states, while the e-ink panel retains the image without continuous power draw.
Module List
| Module ID | Type | Name | Function | Voltage |
|---|---|---|---|---|
| POWER | POWER | BQ24074 USB-C Li-Ion Charger and Power-Path + TPS62740 Buck Converter | Handles USB-C 5V input, single-cell Li-Ion battery charging, power-path management, and efficient 3.3V system rail generation for long battery life | 5V input / 3.7V battery / 3.3V system |
| BATTERY | POWER | Single-cell Li-Ion Battery 3.7V | Portable energy storage for long battery life operation | 3.7V |
| USB_C | MODULE | USB Type-C Receptacle | Provides 5V charging input and optional USB data/programming connection | 5V |
| MCU | MCU | ESP32-S3-WROOM-1 | Main controller for UI, e-book rendering, e-ink display control, local storage access, power management, and cellular modem communication for cloud LLM access | 3.3V |
| DISPLAY | DISPLAY | 4.26-inch E-Ink Display 480x800 with SSD1683-compatible driver | Main ultra-low-power reading display for books, articles, and AI responses | 3.3V |
| TOUCH | SENSOR | GT911 Capacitive Touch Controller | Provides touch input for page navigation, menus, and LLM interaction | 3.3V |
| CELLULAR | MODULE | SIM7080G LTE Cat-M/NB-IoT/GNSS Module | Provides low-power cellular connectivity for cloud LLM access and data synchronization | 3.8V |
| SIM_CARD | MODULE | Nano SIM Socket | Holds SIM card for cellular network access | 1.8V/3.0V |
| ANTENNA_LTE | MODULE | LTE Main Antenna | RF antenna for cellular network communication | RF passive |
| STORAGE | MODULE | microSD Card Socket | Removable storage for books, articles, fonts, and cached AI content | 3.3V |
| FUEL_GAUGE | SENSOR | MAX17048 Li-Ion Fuel Gauge | Monitors battery voltage and state-of-charge for user battery indication and low-power management | 3.3V |
Key Components
11/11 modules matched to real parts. See the BOM tab for the full component table.
BQ24074 USB-C Li-Ion Charger and Power-Path + TPS62740 Buck Converter (BQ24074RGTR)
Exact part number match: BQ24074RGTR corresponds to the BQ24074 Li-Ion charger/power-path IC referenced in the module de
Single-cell Li-Ion Battery 3.7V (88-569747-35E)
No listed candidate matches INR18650-35E, which is a single-cell 3.7V Li-ion battery model; all candidates are connector
ESP32-S3-WROOM-1 (ESP32-S3-WROOM-1-N4R8)
Exact match to the searched part number ESP32-S3-WROOM-1-N4R8; candidate 1 is the specific module listing, while 2 is on
Build Summary
- Difficulty: Advanced
- Estimated time: 18-28 hours
- Tools required: fine-tip soldering iron, hot air station, solder paste, flux, ESD mat, multimeter
See the Build tab for the full step-by-step assembly guide.
Generated by YuanQi AI Design System · Query: eink mini ereader with llm access. good battery