Eight Relays 4A/120V-8A/24V
8-Layer Stackable Card
for Raspberry Pi


Out of stock.  Stock expected in 2-3 weeks. You can backorder. Orders will be filled in the order received.

  • Eight RELAYS with Status LEDs
  • Eight layer stackable to 64 relays
  • Pluggable Connectors 30-16 AWG wires
  • 4 Relays with NO and NC Contacts, rated 4A/120VAC or 4A/24VDC
  • 4 Relays with NO only Contacts rated 8A/48VAC or 8A/24VDC
  • Software self-test
  • Command Line and Python Drivers

In stock (can be backordered)

SKU: SM-H-002 Categories: , , Tags: , , , GTIN: 4782912926291


Raspberry Pi RELAYS: a must for your Home and Industrial Automation projects.

Perfect add-on to your project when you have to control large number of loads. Stackable to 8 layers, the card can add up to 64 relays to each Raspberry Pi in a compact form factor.

Pluggable connectors make the 8-RELAYS card easy to use when multiple cards are stacked up.  Four relays with N.O. contacts can switch up to 8A/48 VAC or 8A/24VDC.  The other four relays with N.O. and N.C. contacts and can switch 4A/120 VAC or 4A/24 VDC. Status LEDs show when relays are on or off.


The card is compatible with all Raspberry Pi versions from Zero to 4. All stacked cards share the I2C bus using only two of the Raspberry Pi’s GPIO pins to manage all eight cards.  This feature leaves the remaining 24 GPIOs available for the user.


  • Electrical endurance: minim 105 cycles at 1,800 operations per hour, full load
  • Mechanical endurance: minim 107 cycles at 18,000 operations per hour, no load


The 8-RELAY card needs 5V to operate and can be powered from Raspberry Pi or from it’s own 2.1mm barrel connector. The relay coils are also powered from the 5V.  The card draws 10mA with all relays off. Each relay needs about 80 mA to turn on. If power is applied to the barrel connector, no other power supply is needed for the Raspberry Pi.


The 8 on-board relays have contacts brought out to heavy duty pluggable terminal blocks,  which make the card easy to use when multiple cards are stacked up.  Four relays have Normal Open and Normal Closed contacts, and are rated 4A/120VAC or 4A/24VDC. The other four relays have only Normal Open contacts brought to the terminal blocks and are rated 8A/48VAC or 8A/24VDC.  Status LEDs show when RELAYS are ON or OFF. If  you need to switch DC loads of more than 24V, our 8-MOSFETS card can handle up to 240VDC.


You can control the 8-RELAY card by writing your program in the language of your choice using the Command Line system, or the Python Driver.  Browser control is very easy using the Node-Red node we provide.


The 8-RELAYS card can be tested before installation by running a simple command from the command line. The card will cycle each relay on and off at 0.5 seconds interval. The clacking noise of the relays and the lighting of the LEDs will assure that all relays are functioning.


Up to eight 8-RELAY cards can be stacked on your Raspberry Pi. Each card is identified by jumpers you install to indicate the level in the stack. Cards can be installed in any order. The three position jumper on the upper right corner of the card selects the stack level. For your convenience, two jumpers are provided with each card. For complex Home Automation tasks you can add to the stack one or more Home Automation cards with analog and digital inputs and outputs.


User’s Guide and Schematics of the 8-RELAYS card can be downloaded from our website.


Install your Raspberry Pi and up to eight 8-RELAYS cards parallel to the DIN-Rail using our  DIN-RAIL Kit Type-1. Install the whole assembly  perpendicular to the DIN-Rail using the DIN-RAIL Kit Type-2.


8-RELAYS add-on card for Raspberry Pi

Raspberry Pi Relays
Raspberry Pi Relays

Mounting hardware and jumpers

Brass stand-offs, screws and nuts
Connector plugs

8 RELAYS Pluggable Connectors


  1. Plug your 8-RELAYS card on top of your Raspberry Pi and power up the system.
  2. Enable I2C communication on Raspberry Pi using raspi-config.
  3. Install the 8-RELAYS software from github.com:
    1. ~$ git clone https://github.com/SequentMicrosystems/8relay-rpi.git
    2. ~$ cd /home/pi/8relay-rpi
    3. ~/8relay-rpi$ sudo make install
  4. ~/8relay-rpi$ 8relay

The program will respond with a list of available commands.

Additional information

Weight150 g
Dimensions10 × 7 × 2 cm

4 ea. 4A/120VAC, 4 ea. 8A/48VAC




1 review for Eight Relays 4A/120V-8A/24V
8-Layer Stackable Card
for Raspberry Pi

  1. Peter Philip (verified owner)

    I’ve been using the 8-relay and rtd cards now for a couple of months and they work great (using for brewery temperature control). Every question I’ve asked has been answered quickly and even a request I had to update the Node-Red module with a new feature was actioned in less than 2 weeks – can’t ask for better than that!

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