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Hardware Configuration



1. RBgrid Controller Overview



The RBgrid controller is a complete solution for electrical power measurement with integrated components on a single board.


Built-in Components

Main Measurement Components

  • Microcontroller: ESP32-WROOM-32E (dual-core, 240 MHz)
  • Voltage Sensor: ZMPT107-1 on GPIO35 (onboard, galvanically isolated from AC mains)
  • Current Sensor Inputs: 2 × 3.5mm Jack sockets
  • Channel 1: GPIO36 (ADC1_CH0)
  • Channel 2: GPIO39 (ADC1_CH3)
  • Compatible with all SCT-013 variants
Zero-Cross Sensor
Uses signal from external RBdimmer modules. Connect pin 3 of the dimmer to GPIO18 of the controller for AC mains synchronization.


Additional Interfaces

Load Control

  • Relay Outputs: 2 channels
  • Relay 1: GPIO15
  • Relay 2: GPIO02

  • Logic level: 3.3V (requires relay driver)

  • Dimmer Interface: RBdimmer module connection

  • Dimmer 1: GPIO15
  • Dimmer 2: GPIO02
  • Zero-Cross: GPIO18 (shared for all dimmers)

Indication and Signaling

  • Buzzer: GPIO4 (audible event alerts)
  • LED1: GPIO17 (status indicator)
  • LED2: GPIO5 (activity indicator)
Universal PINOUT
All ESP32 GPIO pins are accessible for functionality expansion:
- Additional current sensors (ACS712, INA219)
- I2C devices (displays, port expanders)
- SPI devices (Flash/EEPROM memory, SD cards, external ADCs)
- UART devices (RS485, modems)



2. Connection Diagram


Mains Connection

info
     Circuit Breaker
          │
    ┌─────┴─────┐
    │     L     │ Live ───────→ [L] ZMPT107-1 on board
    │           │              
    │     N     │ Neutral ────→ [N] ZMPT107-1 on board
    └───────────┘
WARNING! High Voltage!
- Use a 1-2A circuit breaker for protection
- Perform all work with power disconnected
- Use insulated tools
- Verify absence of voltage with a tester


SCT-013 Current Sensor Connection

  1. Installation on Wire:
  2. Open the SCT-013 sensor clamp
  3. Clamp around ONLY the live wire (L)
  4. Arrow on sensor should point toward the load

  5. Close clamp until it clicks

  6. Connection to Controller:
    ```
    SCT-013 → 3.5mm Jack → Socket on board

Channel 1 (GPIO36): Main supply or large load
Channel 2 (GPIO39): Additional load
```


ACS712 Additional Sensor Connection

For ACS712 sensors, use available GPIO pins:

info
ACS712 Module     →  RBgrid Controller
─────────────────────────────────────
VCC (5V)          →  5V pin
GND               →  GND
OUT               →  GPIO32/33/34 (free ADC1 pins)
ACS712 Calibration
ACS712 sensors require zero-point calibration. With no current flow, output voltage should be VCC/2 (≈2.5V with 5V supply).



3. Controller Power Supply


Main Requirements

  • Voltage: 5V DC
  • Current: minimum 500mA (1A recommended)
  • Stability: ±5% for accurate measurements


Power Connection Options

  1. Via Micro-USB Port:
  2. Use quality 5V/1A USB adapter

  3. Suitable for testing and debugging

  4. Via Power Pins:

  5. 5V → 5V pin on board
  6. GND → GND pin on board
  7. Recommended for permanent installation
Micro-USB Feature
The Micro-USB port is used ONLY for power. For programming and debugging, use a separate USB-UART converter connected to TX/RX pins.
Power Quality is Critical!
Unstable or noisy power will cause:
- Inaccurate measurements (reading drift)
- False Zero-Cross triggers
- Controller resets

Use linear regulators or quality switching power supplies with filtering.



4. First Power-Up


Pre-Power Checklist

  • ☐ Verify all connections are correct
  • ☐ Check for short circuits
  • ☐ Verify 5V power polarity
  • ☐ Current sensors installed correctly (arrow toward load)
  • ☐ Circuit breaker in "OFF" position


    • Power-Up Sequence

    1. Apply 5V Power to Controller
    2. LED1 should flash at startup

    3. Wait 3-5 seconds for initialization

    4. Turn ON AC Circuit Breaker

    5. Controller will start measurements automatically

    6. LED2 will blink with measurement frequency

    7. Check Operation via Serial Monitor
      Connection: 115200 baud, 8N1 Expected output: [RBgrid] System initialized [RBgrid] Voltage: 220.5V, Frequency: 50.02Hz



    5. Advanced Connections


    Relay Connection for Load Control

    info
    RBgrid        Relay Module
─────────────────────────
GPIO15    →   IN1
GPIO02    →   IN2
5V        →   VCC (if 5V compatible)
GND       →   GND
    Tip
    Use optoisolated relay modules to protect the controller from interference and voltage spikes.


    RBdimmer Connection

    info
    RBgrid        RBdimmer Module
──────────────────────────────
GPIO18    →   Pin 3 (Zero-Cross)
GPIO15    →   Pin 4 (PWM Dimmer 1)
GPIO02    →   Pin 4 (PWM Dimmer 2)
GND       →   GND



    6. Common Issues and Solutions

    Problem Possible Cause Solution
    No voltage reading Phase not connected to ZMPT107-1 Check L and N connections
    Zero current reading Sensor on neutral wire Move to live wire
    Unstable readings Poor controller power supply Use stabilized PSU
    Negative power Current sensor reversed Rotate sensor 180°
    No Serial communication Wrong baud rate Set to 115200 baud



    7. Safety Precautions

    DANGER TO LIFE!
    - 220V voltage can be fatal
    - Always disconnect power before changing connections
    - Use RCD (Residual Current Device) for additional protection
    - Never work with electricity alone
    - When in doubt, consult a qualified electrician


    Recommended Safety Equipment

    • Insulated tools (screwdrivers, pliers)
    • Voltage tester
    • Dielectric gloves
    • Safety glasses
    • Rubber mat



    8. Conclusion

    The RBgrid controller provides everything needed to build a power monitoring system. Built-in components and connectors simplify connection, while exposed GPIO pins allow functionality expansion as needed.

    1 RBgrid Controller Overview 2 Connection Diagram 3 Controller Power Supply 4 First Power-Up 5 Advanced Connections 6 Common Issues and Solutions 7 Safety Precautions 8 Conclusion