In the fully loaded state this signal relay board boasts USB, I2C, SPI and RS232 communications. It is currently selling for £120 +VAT.


EasyDAQ are also producing variations :

  • USB only version
  • I2C- SPI only version
  • RS232 only version
  • Any of the configurations can be supplied without onboard power supply or without relay opto-isolation.
  • This means there are a possible 16 variations available to customers. 
  • EasyDAQ offer optional bespoke software

There are 8 opto-isolated, 120V, 3A signal relays and 8 3V to 60V, AC/DC, opto-isolated voltage sensing inputs. The 4 communication options are USB, RS232, I2C and SPI.

This board has three powering options : USB power, External 5V DC with reverse polarity protection, External 7 to 24V DC with reverse polarity protection and Regulated 5V output on the external 5V terminal for powering hardware.  

Two LEDs indicate data transfers between control hardware and the relay board for help with debugging and testing.

Each relay channel or voltage sensing input has its own LED to indicate status.

The board has been designed with future expansion in mind including access to 8, 5V DIO channels connected to the main controller and a further 8 3V3 DIO channels connected to the I2C/SPI port if this option is fitted. The programming pins for the control processor are also available to enable re-purposing of the board by loading application specific software. 

The board is commanded via simple single ASCII characters (+ status byte). I.e a 2 byte pair. These are commands that address each port of the PIC processor device (Hex equivalent shown in brackets). The board can be controlled using a Terminal emulator if connected via USB or RS232. 

In order to test operation, the board can be connected to a serial port and controlled from a terminal emulator program such as “PuTTY” or “Realterm”.

If the I2C/SPI option is fitted then the board can be controlled directly from another processor such as an Arduino, Raspberry Pi, BeagleBone etc.

The communications via the I2C or SPI are managed by a NXP SC16IS750 I2C/SPI to serial converter.

 Operating temp range -20 to +80oC   The product is RoHS compliant and CE marked.

Easydaq is based in Wareham, Dorset and was established in 2002. It is owned by GreenHalse Electronics  1 Designer House, Anglebury Business Park, Sandford Lane Industrial Estate, Wareham, Dorset. BH20 4DY.   Tel 01202 916411