October 28, 2013

Web-controlled relays powered by Arduino

The ability to control relays over the Internet opens up all manner of possible remote-control applications, from simple lights to HVAC and more - and in the following example by "Dr Bit", a garage door. The concept may not be that new, however this implementation offers an interesting method that ensures only one user can control a relay at the same time - that is if the control web page is being viewed by two or more people at the same time, only one can control a relay.

This is done via a random seed system, generated by the Arduino and sent to the client - which has control over the particular relay until the operation is completed. A novel and simple method of ensuring the required amount of control. 

The hardware is quite simple, and relies on an Ethernet-enabled Arduino that controls relays - and could easily be modified for other tasks. To find out about this system, visit the creator's website. And for more, we're on twitter and Google+, so follow us for news and product updates as well.


When putting together your next Internet-enabled Arduino project - save time, space and money with the Freetronics EtherTen. Apart from being fully Arduino Uno-compatible, it has onboard Ethernet, microSD socket, full USB interface (so you don't need a costly FTDI cable just to upload a sketch!) and supports optional Power-over-Ethernet.

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