The relay is an electrically operated switch. Many relays use electromagnets to mechanically actuate the switch, but other operating principles such as solid state relays are also used. Relays are used when you need to control a circuit with a separate low-power signal or control multiple circuits with a single signal



A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a separate low-power signal, or where several circuits must be controlled by one signal.


1. Relayduino (Arduino Compatible I/O Board)


The Relayduino is a real world application; it helps in controlling lights and sprinkler systems, reading sensors and monitoring switches and other digital signals. It is also Arduino compatible controller and can be programmed with Arduino IDE for stand-alone operation. This project is more advanced than the simple getting started examples in the Exosite Arduino Library or the basic Arduino Temperature Monitor. This example will show both writing to and reading from the Exosite platform. We are providing the complete information about how to connect your Relayduino devices with Exosite portal. Sing up on Exosite portal to add your Relayduino devices with internet of things solutions.



  • Relayduino – 12 Volt or 24 Volt
  • Arduino Ethernet Shield
  • A 2×3 Male Header
  • Set of Arduino Headers
  • 12 or 24 Volt Power Supply


You’ll need to install the Exosite library. Download that repo and put in in the Arduino libraries folder. The readme has more specific information about installing it.

To the Cloud

Login to your account. If you do not have one, you can create a free community account. To add the Relayduino to your account.

  • Go to your devices page and click on “+ Add Device”.
  • Select “I want to add an unlisted device.”
  • Enter the following information: Vendor: exosite Client Model: oc-kta-223 Serial Number: Your Ethernet Shield’s MAC Address in the form 00:00:00:00:00:00 Name: Whatever you’d like your device to be called.
    • Copy the CIK that is shown into the cikData variable in the Arduino ID

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2. Arduino Web Control of Relay and Lights with Ethernet Shield


This project is based on three projects (pin control via ethernet, led control via ethernet, web server tutorial).

It is designed to control Relay via Arduino and Ethernet Shield.

Users connect the Server as a client with Web then turn on and off the button to control Relay offered on Web page.