Alex Petrochenko
8f0df02e77
Complete reverse engineering of TJ-56-654 weather clock from AliExpress. Security fixes: - Eliminated WiFi password leak vulnerability - Removed dependency on Chinese cloud services (QWeather) - Secure WiFiManager captive portal setup - No hardcoded credentials Features: - Fully async architecture (zero blocking operations) - OTA firmware updates (web + ArduinoOTA) - NTP time sync with timezone + DST support - Open-Meteo weather API (free, no registration) - 3 display modes: time, weather, sunrise/sunset - REST API + web interface - EEPROM config persistence Performance: - Loop time: <1ms (was 10ms+) - Memory: 409KB flash (38%), 38KB RAM (46%), 62KB IRAM (94%) - Zero blocking delays Hardware: - ESP-01S (ESP8266EX, 1MB flash) - GM009605v4.3 OLED display (128x64, I2C) - Custom I2C mapping: SDA=GPIO0, SCL=GPIO2 Documentation: - Complete installation guide - Hardware specifications - API documentation - Troubleshooting guide - Version history v1.5 → v1.9.1 Built with Claude Code (Opus 4.5) Author: Andrey Petrochenko Date: 2026-01-03
207 lines
5.9 KiB
Markdown
207 lines
5.9 KiB
Markdown
# Hardware Documentation
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## Device Specifications
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### Original Product
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- **Name**: ESP8266 Mini Weather Clock Kit
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- **Model**: TJ-56-654
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- **Source**: [AliExpress Link](https://pt.aliexpress.com/item/1005008333782531.html)
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- **Price**: ~$12 USD
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- **Dimensions**: 40mm x 40mm x 43mm
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### Components
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#### ESP-01S WiFi Module
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- **Chip**: ESP8266EX
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- **Flash**: 1MB (8Mbit)
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- **RAM**: 80KB total (32KB instruction, 48KB data)
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- **CPU**: 80MHz (can be overclocked to 160MHz)
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- **WiFi**: 802.11 b/g/n (2.4GHz only)
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- **GPIO**: 2 usable pins (GPIO0, GPIO2)
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- **Voltage**: 3.3V (NOT 5V tolerant!)
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#### Display Module
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- **Model**: GM009605v4.3
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- **Type**: OLED (Organic LED)
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- **Resolution**: 128x64 pixels
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- **Size**: 0.96 inches diagonal
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- **Controller**: SSD1306 or SH1106 compatible
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- **Interface**: I2C
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- **I2C Address**: 0x3C (default), 0x3D (fallback)
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- **Colors**: Monochrome (white on black)
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#### Power Supply
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- **Input**: 5V via Micro-USB
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- **Regulator**: Onboard 3.3V LDO (on main PCB)
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- **Current**: ~80-120mA typical
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#### Case
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- **Material**: Transparent acrylic
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- **Pieces**: 6 (top, bottom, 4 sides)
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- **Assembly**: Brass standoffs and M2.5 screws
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## Pinout
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### ESP-01S Pin Configuration
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```
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┌─────────────────┐
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│ ESP-01S Module │
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├─────────────────┤
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│ │
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│ [antenna] │
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│ │
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│ 3V3 │ │ GND │
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│ TX │ │ GPIO0 │ ← I2C SDA (custom mapping!)
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│ RX │ │ GPIO2 │ ← I2C SCL (custom mapping!)
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│ EN │ │ GND │
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│ │
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└─────────────────┘
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```
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### Pin Functions
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| Pin | Standard Use | This Project |
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|-----|--------------|--------------|
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| 3V3 | Power (3.3V) | Power |
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| GND | Ground | Ground |
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| TX | UART TX | Serial debug output |
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| RX | UART RX | Serial input (flashing) |
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| GPIO0 | General I/O | **I2C SDA** (data line) |
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| GPIO2 | General I/O | **I2C SCL** (clock line) |
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| EN | Chip Enable | Pulled high (always on) |
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**⚠️ Important**: This project uses **non-standard I2C pin mapping**!
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- Typical ESP8266: SDA=GPIO4, SCL=GPIO5
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- **This device**: SDA=GPIO0, SCL=GPIO2
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### I2C Connection
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```
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ESP-01S OLED Display
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─────────────────────────────
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3V3 → VCC
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GND → GND
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GPIO0 → SDA
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GPIO2 → SCL
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```
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### Programming Connection (FTDI)
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```
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FTDI Adapter ESP-01S
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──────────────────────────
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3V3 → 3V3
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GND → GND
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TX → RX
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RX → TX
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GND → GPIO0 (boot mode - connect only during programming)
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```
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**Programming Mode:**
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1. Connect GPIO0 to GND
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2. Power on the ESP-01S
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3. Remove GPIO0-GND connection
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4. Upload firmware
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5. Power cycle to run new code
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## PCB Layout
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The main PCB (TJ-56-654) contains:
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- ESP-01S socket (8-pin header)
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- OLED display connector (4-pin header)
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- 3.3V voltage regulator (AMS1117-3.3)
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- Micro-USB connector for power
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- Bypass capacitors
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## Memory Map
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### Flash Memory (1MB)
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```
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0x00000000 - 0x00010000 : Bootloader (64KB)
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0x00010000 - 0x0007C000 : Firmware (~470KB max for OTA)
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0x0007C000 - 0x00080000 : EEPROM emulation (16KB)
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0x00080000 - 0x000FA000 : OTA partition (~470KB)
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0x000FA000 - 0x000FB000 : WiFi config (4KB)
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0x000FB000 - 0x00100000 : System reserved (20KB)
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```
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### RAM Layout
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```
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Total: 80KB
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├── IRAM (Instruction): 32KB
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│ ├── Used: ~62KB (94%) ← Critical!
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│ └── Free: ~4KB
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└── DRAM (Data): 48KB
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├── Heap: ~40KB free
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├── Stack: ~4KB
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└── Globals: ~4KB
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```
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## Power Consumption
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| Mode | Current | Power @3.3V |
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|------|---------|-------------|
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| Active (WiFi on) | 80-120mA | 264-396mW |
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| Display on | +15mA | +50mW |
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| Deep sleep | ~20µA | ~66µW |
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**Note**: This firmware does not use deep sleep (clock is always-on).
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## Hardware Modifications
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### Optional Improvements
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1. **External antenna**: Solder U.FL connector for better WiFi range
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2. **Temperature sensor**: Add DHT22 or BME280 to GPIO (requires software changes)
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3. **Buttons**: Add physical buttons for display control (requires free GPIO)
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4. **Battery backup**: Add 18650 cell + TP4056 charger for UPS functionality
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### Pin Availability
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ESP-01S has very limited GPIO:
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- **GPIO0**: Used for I2C SDA (can't use for other purposes)
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- **GPIO2**: Used for I2C SCL (can't use for other purposes)
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- **TX/RX**: Can be repurposed (breaks serial console)
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For additional peripherals, consider upgrading to ESP-12F or ESP32.
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## Troubleshooting
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### Display not working
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- Check I2C address: Try 0x3C and 0x3D
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- Verify pin mapping: SDA=GPIO0, SCL=GPIO2
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- Check power: Display needs 3.3V
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- Test with I2C scanner (`/api/i2c-scan`)
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### WiFi connection fails
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- ESP8266 only supports 2.4GHz (not 5GHz)
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- Check power supply: Weak USB port can cause brownouts
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- Some routers don't like ESP8266 - try different channel
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### Bootloop/crashes
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- Check IRAM usage: Must be <95%
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- Verify flash mode: Should be "DIO" not "QIO"
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- Bad power supply: Use quality USB cable
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### Can't flash firmware
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- GPIO0 must be LOW during boot for programming mode
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- Some FTDI adapters need DTR/RTS wiring for auto-reset
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- Baud rate: Try 115200 (default) or 57600 if errors
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## Datasheets
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- [ESP8266EX Datasheet](https://www.espressif.com/sites/default/files/documentation/0a-esp8266ex_datasheet_en.pdf)
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- [ESP-01S Pinout](https://components101.com/wireless/esp8266-pinout-configuration-features-datasheet)
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- [SSD1306 OLED Controller](https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf)
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## Safety Warnings
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⚠️ **Do NOT connect 5V to ESP-01S GPIO pins** - they are NOT 5V tolerant!
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⚠️ **Use 3.3V FTDI adapter** - 5V will permanently damage the ESP8266
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⚠️ **Check polarity** - Reversing power can destroy the module
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⚠️ **ESD sensitive** - Touch grounded metal before handling board
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