Remotely Control a Relay over the Internet

ioBridge’s technology is often used for real-time control over the internet.

This tutorial shows you how simple this is to set up using a DPDT Relay Board (FB-3) as the switch.

Project Components

Step 1 – Plug in a Relay Board

In this tutorial we are going to assume that we still have a temperature sensor plugged into channel 1 (from the earlier tutorials) although it is not necessary.

The first step is to plug in a DPDT Relay Board (FB-3) into Channel 2 of an IO-204 or IO-204-PRO module. If you have a Channel Tester (FB-1) you can also plug it into the Relay Board to see if the relay is on or off. The Relay Board includes two so-called double-pole double-throw (DPDT) switches that are wired as shown the in the image below.

This board can be used to switch on or off two circuits. In the example above a light bulb and battery circuit is wired between the NC and C terminals of one of the relay switches. When the digital output of channel 2 is low, the switch is on and the light bulb will light up. Similarly connecting the wires between NO and C will result in the light bulb being off when the digital output is low.

The Channel Tester (FB-1) shows the state of the relay and the red LED light up when the relay is off (NC and C connected, digital output low or 0) and the green LED is on when the relay is on (NO and C connected, digital output high or 1).

Step 2 – Create an On-Off Switch Control and Place it on a Dashboard

Sign In to your account at (or if you are using a PRO module). Click on the Widgets menu and then click on Create Widget. Select Digital Output Control and then click Next.

Select the module with the relay and click Next. Select Channel 2 and click Create Widget. You should then see a page similar to the one below. Change the Label to Switch and click on the + icon next to Dashboard to place your switch control on your dashboard.

Click on Dashboard on the navigation menu. You should now see your On-Off control on your dashboard.

You can now click the On and Off buttons to switch the relay (and your device that is wired up) on and off. Note how fast it is!