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Complete IoT monitoring platform for Acuvim II power meters via ESP32. Firmware (Phases 1-7): - ESP32-WROVER-B (TTGO T-Call v1.4) with RS485 Modbus RTU - WiFi STA+AP concurrent mode with GSM/GPRS failover - Transport abstraction layer with 4 priority modes - MQTT protocol with 20 commands, LWT, QoS, exponential backoff - SD card offline buffering with JSONL rotation and non-blocking drain - OTA firmware updates with dual partition rollback protection - Watchdog timer, crash loop detection, Acuvim health monitoring - Captive portal provisioning with AP mode Console backend (Phase 8): - .NET 10 minimal API with PostgreSQL + EF Core - JWT authentication, SignalR real-time updates - MQTTnet 5.x bridge service with health monitoring - Device, telemetry, firmware, alert, group management - Rate limiting, security headers, Swagger/OpenAPI Frontend (Phase 9): - React 18 + TypeScript + Vite with Ant Design 5 - ECharts telemetry visualization, TanStack Query - SignalR live updates, device management UI - Dashboard, fleet management, firmware deployment Testing & Production (Phase 10): - 28 firmware unit tests (Modbus, JSON, config, version) - 23 xUnit backend tests (device, telemetry, command, alert) - Docker Compose with nginx, TLS MQTT, PostgreSQL - Production deployment, commissioning, and troubleshooting docs Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
11 KiB
11 KiB
Hardware Wiring Guide
Wiring diagrams for ESP32 TTGO T-Call v1.4 with RS485 Modbus connection to Acuvim II power meter, optional SD card module, and GSM antenna.
ESP32 TTGO T-Call v1.4 Pinout (Relevant Pins)
┌──────────────┐
│ TTGO T-Call │
│ v1.4 │
3V3 ───┤ 3V3 VIN ├─── 5V
GND ───┤ GND GND ├─── GND
┤ GPIO36 GPIO23├─── SPI MOSI (SD)
┤ GPIO39 GPIO22├───
┤ GPIO34 GPIO1 ├─── TX0 (USB Serial)
┤ GPIO35 GPIO3 ├─── RX0 (USB Serial)
┤ GPIO32 GPIO21├───
┤ GPIO33 GPIO19├─── SPI MISO (SD)
┤ GPIO25 GPIO18├─── SPI SCK (SD)
RS485 DE/RE ───┤ GPIO4 GPIO5 ├─── SD CS
┤ GPIO0 GPIO17├─── TX2 (RS485 DI)
┤ GPIO2 GPIO16├─── RX2 (RS485 RO)
┤ GPIO15 GPIO14├───
┤ GPIO13 GPIO12├───
└──────────────┘
Built-in SIM800L: GPIO26 (TX), GPIO27 (RX)
Built-in SIM slot on bottom of board
Note: The TTGO T-Call v1.4 has SIM800L built into the board. No external GSM module wiring is needed.
RS485 Module Connection (MAX485 / MAX3485)
Connect the ESP32 to an RS485 transceiver module, then to the Acuvim II.
Wiring Table
| RS485 Module Pin | ESP32 Pin | Description |
|---|---|---|
| DI (Data In) | GPIO17 (TX2) | UART2 transmit |
| RO (Receiver Out) | GPIO16 (RX2) | UART2 receive |
| DE (Driver Enable) | GPIO4 | Direction control |
| RE (Receiver Enable) | GPIO4 | Direction control (active low, tied to DE) |
| VCC | 3.3V | Power supply |
| GND | GND | Ground |
| A | Acuvim II A (+) | RS485 bus positive |
| B | Acuvim II B (-) | RS485 bus negative |
Wiring Diagram
ESP32 TTGO T-Call MAX485 Module Acuvim II
┌─────────────────┐ ┌──────────────┐ ┌────────────┐
│ │ │ │ │ │
│ GPIO17 (TX2) ───┼──────────┤ DI A ├──────────┤ A (+) │
│ │ │ │ │ │
│ GPIO16 (RX2) ───┼──────────┤ RO B ├──────────┤ B (-) │
│ │ │ │ │ │
│ GPIO4 ──────────┼────┬─────┤ DE │ │ GND ───────┤
│ │ └─────┤ RE │ │ │
│ │ │ │ │ │
│ 3V3 ───────────┼──────────┤ VCC │ │ │
│ │ │ │ │ │
│ GND ───────────┼──────────┤ GND │ │ │
│ │ │ │ │ │
└─────────────────┘ └──────────────┘ └────────────┘
DE and RE tied together: GPIO4 drives both pins. HIGH = transmit mode, LOW = receive mode. The firmware toggles this automatically during Modbus transactions.
Acuvim II RS485 Terminal Block
The Acuvim II has an RS485 terminal block on the bottom of the meter.
Acuvim II Bottom Terminal Block
┌─────────────────────────────────┐
│ ... │ A (+) │ B (-) │ GND │ ...│
└─────────────────────────────────┘
- A (+): Connect to MAX485 module A pin
- B (-): Connect to MAX485 module B pin
- GND: Connect to common ground with ESP32
Acuvim II Modbus Settings
Configure on the meter's front panel:
- Protocol: Modbus RTU
- Address: 1 (default, configurable 1-247)
- Baud Rate: 9600 (default, configurable)
- Parity: None
- Stop Bits: 1
SD Card Module Connection (Optional)
For offline buffering, connect a standard SPI SD card module.
| SD Module Pin | ESP32 Pin | Description |
|---|---|---|
| MOSI | GPIO23 | SPI Master Out Slave In |
| MISO | GPIO19 | SPI Master In Slave Out |
| SCK | GPIO18 | SPI Clock |
| CS | GPIO5 | Chip Select |
| VCC | 3.3V | Power (use 3.3V modules only) |
| GND | GND | Ground |
ESP32 TTGO T-Call SD Card Module
┌─────────────────┐ ┌──────────────┐
│ │ │ │
│ GPIO23 (MOSI) ──┼──────────┤ MOSI 3V3 ├─── 3V3
│ │ │ │
│ GPIO19 (MISO) ──┼──────────┤ MISO GND ├─── GND
│ │ │ │
│ GPIO18 (SCK) ───┼──────────┤ SCK │
│ │ │ │
│ GPIO5 (CS) ─────┼──────────┤ CS │
│ │ │ │
└─────────────────┘ └──────────────┘
Use a micro SD card formatted as FAT32. The firmware creates the /telemetry/ directory on first use.
SIM Card Insertion
The TTGO T-Call v1.4 has a SIM card slot on the bottom of the board.
Bottom of TTGO T-Call v1.4
┌─────────────────────────────┐
│ │
│ ┌─────────────────┐ │
│ │ SIM Card Slot │ │
│ │ (micro SIM) │ │
│ │ Insert with │ │
│ │ contacts DOWN │ │
│ └─────────────────┘ │
│ │
└─────────────────────────────┘
- Use a micro SIM (not nano — use adapter if needed)
- Insert with contacts facing down toward the PCB
- SIM must have data plan enabled
- SIM PIN must be disabled (or configure PIN in firmware)
GSM Antenna
The TTGO T-Call v1.4 has an IPX (U.FL) connector for the GSM antenna.
- Attach the supplied GSM antenna to the IPX connector
- For better signal in metal enclosures, use an external antenna with SMA connector and IPX-to-SMA pigtail
- Position antenna away from the ESP32 and RS485 module to reduce interference
Power Supply
USB Power (Development)
Connect micro-USB cable to the TTGO T-Call. Provides 5V via USB.
External Power (Production)
| Parameter | Value |
|---|---|
| Input voltage | 5V DC (via VIN pin) |
| Current requirement | 500mA minimum (GSM peaks at 2A) |
| Recommended supply | 5V 2A regulated DC adapter |
For GSM operation, a supply capable of 2A peak current is required due to SIM800L transmission bursts.
DC Power Supply ESP32 TTGO T-Call
┌──────────────┐ ┌──────────────────┐
│ │ │ │
│ +5V ─────────┼────────────┤ VIN │
│ │ │ │
│ GND ─────────┼────────────┤ GND │
│ │ │ │
└──────────────┘ └──────────────────┘
Do not power via USB and VIN simultaneously unless the USB is only for serial monitoring.
Complete Wiring Diagram
ESP32 TTGO T-Call v1.4
┌───────────────────────┐
│ │
┌─────────┐ GPIO17 (TX2)──┤ 3V3──┼──┐
│ MAX485 ├──DI │ │ │
│ │ │ GND──┼──┼──┐
│ ├──RO──GPIO16 (RX2)┤ │ │ │
│ │ │ [SIM800L BUILT-IN] │ │ │
│ ├──DE──GPIO4───────┤ [SIM SLOT BOTTOM] │ │ │
│ ├──RE──┘ │ │ │ │
│ │ │ GPIO23───┼──┼──┼──MOSI──┐
│ VCC───┼──────────────────┼── 3V3 │ │ │ │
│ GND───┼──────────────────┼── GND GPIO19───┼──┼──┼──MISO─┤ SD Card
│ │ │ GPIO18───┼──┼──┼──SCK──┤ Module
│ A────┼──Acuvim A (+) │ GPIO5────┼──┼──┼──CS───┤
│ B────┼──Acuvim B (-) │ │ │ │ VCC──┘
└─────────┘ │ │ └──┼──GND
│ VIN──────┼──5V │
GSM Antenna ─────IPX─┤ │ │
└───────────────────────┘ │
│
┌─────────────────┐ │
│ Acuvim II │ │
│ RS485 Terminal │ │
│ A (+) ├─ MAX485 A│
│ B (-) ├─ MAX485 B│
│ GND ├──────────┘
└─────────────────┘
Cable Recommendations
| Connection | Cable Type | Max Length |
|---|---|---|
| RS485 (ESP32 to Acuvim) | Shielded twisted pair (STP), 22-24 AWG | 1200m |
| SPI (ESP32 to SD) | Short jumper wires | 15cm |
| USB (development) | Micro-USB data cable | 2m |
| Power (production) | 22 AWG stranded | 3m |
For RS485 runs over 10m, use 120 ohm termination resistors at each end of the bus.