I2C DIY 8 Outputs 12V Controller

Overview

This is a small DIY electronics module designed to control multiple 12V loads (like LEDs, small motors, solenoids) using a microcontroller via the I²C communication protocol. It allows you to expand the number of outputs without adding extra pins to the main microcontroller.

Specifications

1. Power Supply:

   • Input Voltage: 12V DC

   • Current Capacity: Must match the total load of the outputs. If each output drives, say, 1A, the PSU should handle 8–10A with some margin.

2. Connectivity:

   • I²C Interface: For communication with microcontrollers (Arduino, ESP32, Raspberry Pi, etc.).

   • SCL / SDA lines with pull-up resistors (typically 4.7kΩ–10kΩ to 3.3V or 5V depending on MCU logic level).

   • Multiple devices can be connected via I²C using different addresses.

3. Outputs:

   • 12V Outputs: 8 channels total

   • Each output can switch a load up to the maximum current of the transistor or MOSFET used.

   • PWM Control: Allows dimming of LEDs or speed control of motors. Typically done via a microcontroller sending PWM signals, or via a dedicated PWM expander chip (like PCA9685).

4. Expander:

   • 7-channel expander: This could mean using a device like MCP23017 (16-bit GPIO expander) or PCA9685 (16-channel PWM) to extend output pins.

   • The expander communicates via I²C and allows the controller to handle more outputs without using more MCU pins.

Typical Components

1. Microcontroller / Master device: Arduino, ESP32, Raspberry Pi

2. I²C Expander IC: PCA9685 (PWM) or MCP23017 (digital on/off)

3. Switching elements:

   • N-channel MOSFETs (logic-level) for switching 12V loads

   • Optional flyback diodes for inductive loads

4. Connectors / Terminals: Screw terminals for easy 12V load connection

5. Decoupling capacitors: For stable operation

6. Pull-up resistors: For I²C lines

Functionality

• Connect the controller to a 12V power supply.

• Connect the SDA/SCL lines to a microcontroller.

• Each output can be turned on/off or PWM dimmed.

• If using a 7-channel expander, the controller can manage up to 15 outputs (8 on main + 7 on expander) from one I²C address or multiple addresses.

Applications

• LED lighting control

• Small motor or fan control

• Solenoid or actuator control

• DIY home automation projects

• Robotics
   

Compatible with Wifi DIY MQTT Generic Controller and MQTT api