USB/RS485 Relay I/O Controller (Relayduino)
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SKU : KTA-223
Quantity on Hand : 3
Skill Level : Assembled and Tested
ROHS Compliant

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KTA-223 DEV-09526

129.00 129.0 USD 129.00


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KTA-223 can now be powered 6.5-36VDC, therefore KTB-223 has been discontinued.

Description: The KTA-223 is a USB or RS485 controlled IO module for interfacing PCs to real world applications, such as controlling lights and sprinkler systems, reading sensors and monitoring switches and other digital signals. The Relays are capable of switching up to 5A at 250VAC, 10A at 120VAC and 10A at 24VDC but the PCB tracks will only handle up to about 5A. A simple ASCII protocol allows control from Windows/Mac/Linux using either USB Virtual COM drivers or RS485. Additionally, multiple devices can be connected to one RS485 bus, allowing control of many devices from one USB port. 

The controller is based on the hardware of the Arduino physical computing controllers. It can be programmed as a stand-alone controller using the free, open source Arduino environment. Internally, the controller is “shield compatible”, allowing the use of many extension boards designed for the Arduino Deumilanove. As shipped the controller is loaded with a sketch that receives simple commands over the USB or RS485 serial port and switches relays or responds with the status of inputs. 

Multiple controllers can be connected to one or more PCs in an RS485 network. Each controller can be assigned an address and will respond to commands addressed to them. 


  • 8 Relay Outputs 5A 250VAC
  • 4 Opto-Isolated Inputs 5-30VDC
  • 3 Analog Inputs (10 bit)
  • Connections via Pluggable Screw Terminals
  • 0-5V or 0-20mA Analog Inputs, Jumper Selectable
  • 5A Relay Switching
  • Power Indicator LED
  • All enclosed in Professional looking plastic case
  • Arduino Compatible
  • Accepts Arduino Shields (Ethernet / XBee)
  • USB Virtual Serial Port or RS485 Input
  • Easily connect multiple units far apart by RS485
Additional Details:
An example program has been written in both Visual Basic 6 and VB .Net to show you how to interface with the KTA-223 using a PC.

Light Flasher Software
Our Light Flasher software for the KTA-223 allows you to sequence the relays in patterns. This is designed for Christmas lights, trapshooting and other simple time loop controls.
Time Clock Software
Our Time Clock software for the KTA-223 called Time-Clock allows you to switch on relays at certain times of the day and days of the week. Can be used to control lighting and watering for plants, etc.

Web Interface Sketch
Using the WebUi sketch and an Ethernet shield allows you to control the IO from a web browser.