6 channel RS485/Serial controlled Relay board with built in ATtiny2313A Microcontroller.The relays can also be controlled by Serial(TTL),SPI,I2C(TWI) protocols.
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PCB Silk Screen


ATtiny2313 based Serial/RS485/SPI/I2C controlled 6 Channel Relay Board

The Board consists of a ATtiny2313 controlled 6 channel Relay which can be controlled by either Serial(TTL) /RS485 /SPI or I2C Protocol.The board helps you to save precious microcontroller pins by using serial protocols for control and coordination.

The board provides easy and cost effective means to interface and control 6 SPDT relays to your microcontroller board like Arduino/AVR/8051/Raspberry Pi or PIC using a two wire serial protocol.

The built in ATtiny2313 microcontroller along with the MAX485 RS485 tranciever chip can be used for decoding various protocols like ModBUS.


  • ATtiny2313 based Microcontroller for Protocol Decoding and control
  • 3 pin MAX485 based RS485 Port for controlling the Relays using RS485 protocol.
  • 6 SPDT Relays rated at 7A/250VAC
  • 3 bit Address selection using Jumpers for networked opeartion
  • SPI based Relay Control
  • I2C based Relay Control
  • RS485 based Relay Control
  • Serial (TTL) based Relay Control
  • Indicator LED's to visualize relay status
  • Built in Voltage regulator for connecting with standard 12V DC adapters
  • Software support in C (for ATTiny) and C# (for PC based Control).

Code Support

The microcontroller side code for ATTiny2313 is written in Embedded C and compiled using AVR GCC. The PC side code used for controlling the relays from PC is written in C# and can be compiled using MS Visual Studio or SharpDevelop

Repo Contents

  • Circuit