Eight MOSFETS 8-Layer Stackable HAT for Raspberry Pi

The Eight MOSFETS 8-Layer Stackable HAT is an expansion card for the Raspberry Pi, featuring eight channels split between high current (12A/24V) and high voltage (4A/240V) capabilities. It's stackable up to 8 layers, providing up to 64 outputs per Pi. The card is easy to use with pluggable connectors and status LEDs, and is compatible with all Raspberry Pi versions, efficiently using just two GPIO pins for I2C bus communication.

Power-wise, it needs 5V and can be powered either from the Raspberry Pi or its own connector, drawing about 50mA. The card has a six-position DIP switch for RS485 port source selection and stack positioning. It supports up to eight stacked cards, with adjustable settings for stack level.

The RS485 port can be configured for direct Raspberry Pi communication or as a MODBUS slave, depending on the DIP switch settings. Additionally, it includes reverse power supply protection and an RS485 terminator for the end of a chain. A notable feature is the shutdown push button, which safely powers down the Raspberry Pi to prevent SD Card damage. This button, connected to GPIO 26, requires a script for shutdown command execution.

Revision History

The latest version of the 8-MOSFET card (V5.0) has the following improvements

• On board processor permits proportional load control using PWM at 1kHz
• RS485 port connected to the local processor permits operation as MODBUS RTU slave, replacing the Raspberry Pi with any PLC
• Heavy duty, 5mm pluggable connectors can control loads up to 12A
• High current channels are galvanically separated from the High Voltage channels
• TVS diode protection on high current outputs, diode protection on high voltage
• All jumpers replaced with DIP Switches
• Software compatible with previous version

Features

• Eight MOSFETS 8-Layer Stackable HAT for Raspberry Pi
• Status LEDs on each output
• Pluggable Connectors 24-12 AWG wires
• Four High Current Loads, 12A/24VDC
• Four High Voltage Loads, 2A/240VDC
• RS485 with TVS protection and MODBUS protocol
• Reverse polarity power supply protection
• General purpose pushbutton
• All mounting hardware included: brass stand-offs, screws and nuts
• Software self-test
• Uses only I2C port (address 0x20..0x27 or 0x38..0x3f ), all GPIO pins available

 Resources

• User's Guide V3.0
• Hardware Schematic V2.0
• Hardware Schematic V4.0
• Hardware Schematic V5.0
• Command Line
• Python Library
• Node Red Nodes
• 2D CAD Drawing
• 3D STEP Model
• 3D Printing Enclosure
• RoHS and REACH Compliance Declaration

Package Contents

• 1x 8-MOSFETS Stackable HAT for Raspberry Pi
• Four M2.5x18mm male-female brass standoffs
• Four M2.5x5mm brass screws
• Four M2.5 brass nuts
• Connector Plugs