Mosfet driver Solid State Relays on a DIN-rail

Microchip's 8-Bit I/O Expander with I²C Interface

PCB (Printed Circuit Board):

Click on the Schematic for a larger view:

MCP23008
Microchip's 8-Bit I/O Expander with I²C Interface

Features:

• 8-Bit Remote Bidirectional I/O Port
• High-Speed I2C Interface - 100 kHz, 400 kHz and 1.7 MHz
• Hardware Address Pins
• Configurable Interrupt Output Pin
  • Configurable as active-high, active-low or open-drain
• Configurable Interrupt Source
  • Interrupt-on-change from configured defaults or pin change
• Polarity Inversion Register to Configure the Polarity of the Input Port Data
• External Reset Input
• Low Standby Current: 1 µA (max.)
• Operating Voltage - 1.8V to 5.5V
• The device is supplied in 18-pin SOIC (300 mil)

LD1117S33TR
STMicroelectronics Adjustable and fixed low drop positive voltage regulator

Features:

• Fixed output voltage of 3.3 Volt
• Output current up to 800 mA (is a bit overkill ;-) )
• Low dropout voltage (1 V typ.)
• Internal current and thermal limit
• Supply voltage rejection: 75 dB (typ.)
• Only a very common 10 µF minimum capacitor is needed for stability
• The device is supplied in SOT-223

PMV230ENEA
NXP Semiconductors N-channel Trench MOSFET

Features:

• N-channel enhancement mode FET in a small SOT23 (TO-236AB) package
• Logic level compatible
• Very fast switching
• Trench MOSFET technology
• Drain-source voltage 60 V
• Gate-source voltage −20 V - +20 V
• Drain current 1.5 A
• ElectroStatic Discharge (ESD) protection > 2 kV HBM

Graphic symbol:

MKDS 3/2
PCB terminal block, Phoenix Contact

Features:

• No. of pos.: 2
• Type: PC terminal block, can be aligned
• Product line: COMBICON Terminals M
• Conductor cross section: 2.5 mm²
• Color: Green
• Pitch: 5 mm
• Connection method: Screw connection with tension sleeve
• Nominal current: 24 A
• Nominal voltage: 400 V
• Connection direction: 0 °
• Order No.: 1711026

Board pinout

Power pins
• Positive Power
  • 5 Volt:
    • goes to 3.3 Volt voltage regulator
    • Raspberry Pi
  • 24 Volt, goes to the relays
• GND - This is common ground for power and logic.
  • 5 Volt
  • 24 Volt
  • I²C

I²C Data pins
• SCL - this is the I²C clock pin
• SDA - this is the I²C data pin

Reset and Interrupt pins
• RST - This is the reset pin. Connect this pin to ground to reset the board.
• INT - The MCP23008 has interrupt capabilities. If you want to have a quick way of telling if any of the GPIO's changed.

Check MCP23008 address

Type into the cli: $ sudo i2cdetect -y 1 There should be a HEX number into the matrix. Default is 0x20.
You can set the I²C address by tying the ADDR pins to power or ground, for up to 8 unique addresses.

This board/chip uses I²C 7-bit address between 0x20-0x27, selectable with jumpers.
The table below shows all possible addresses, and whether the pin(s) should be High (closed) or Low (open).

Address	A0	A1	A2
0x20 (default)	L	L	L
0x21	H	L	L
0x22	L	H	L
0x23	H	H	L
0x24	L	L	H
0x25	H	L	H
0x26	L	H	H
0x27	H	H	H

On the top of the board are three address jumpers, labeled A0, A1, and A2:

PCB and aluminium L-profile with a DIN Railadapter