# Use power line to communicate between devices - simple communication

So I am a google programmer getting interested in hardware hacking.

What I want to do: Use Arduino or a similar microcontroller to control the lighting in my house, of course for as cheap as humanly possible.

Proposed Method: Using the power line itself for the communication (similar to ethernet over AC). A base station would be plugged into one power outlet in the house, that would send signals to N number of microcontrollers which are plugged into other power outlets. The communication between the devices needs to be very simple. Sending a packet containing the UID of the microcontroller to trigger, and command code (on/off). This command would trigger a relay to switch the power current on/off.

Reason for Proposed Method: Most devices that do this use Wifi. Which having a Wifi device on every outlet would be very, very expensive. Having the base station only be Wifi would decrease costs tremendously.

• And your question is...? (add it to your question) – Keelan Mar 11 '13 at 19:49
• Have you thought about X10 products? Please note that anything directly connected to the MAIN's is a potential fire and shock hazard. Let alone bridging mains and other electronics. X10 won't directly bridge, but rather uses a wireless to bridge. Commercial design's have there circuits and construction tested for liability reasons. Noting that mains needs to with stand lightening strikes. Voltages. DIY at your own risk. – mpflaga Mar 11 '13 at 20:05
• The question is what is the best way to go about it. Like I said, im more of a software developer, I know little about hardware. I understand I need relays, but what other chips/modules would be needed. Thanks, – Quinton Pike Mar 11 '13 at 20:15
• after these few years that passed esp8266 wifi microcontroler 3 units for ~10$– user95138 Dec 22 '15 at 12:34 ## 2 Answers The best way is to use an off the shelf part. So you don't have to worry about burning your house down. That is why I mention X10. There is already a library to interface to X10 As how to do it discretely, look at the Mamba Shield it is a hacker alternative to the X10. You can see from their schematic, there is a lot to it. Note there are no relays. And they have taken HiPot in to consideration of there components and design. Note the Mamba does not have UL or equivalent. So while it is likely safe, it has not been proven to be. And it is just as expensive as the wifi shield. The X10 is not cheap either. But it is proven. Not sure whats UL equivalent is. More research show the X10 Pro products (different than X10) are actually UL tested. Where the PSC04 is equivalent to PL513 and PSC05 is equivalent to the TW523. both of which appear cheaper then X10's original product. Where as it is hard to get any solution much cheaper. If you do it your self discretely low volume pricing of part costs is expensive. And off the shelf items have overhead. The cheapest way is to use a$4@ RF Link Transmitter and RF Link Receiver pair.

You're in an area with a lot of off the shelf ready-to-use products directly designed for home automation.

If you need a custom electronic design and lots of bandwidth, look into HomePlug http://www.homeplug.org/. That's pretty much WiFi over powerline by the way. Other systems include Wattwave and Insteon (a successor to X10).

The older X10 protocol is unsuitable for any use at this point. It is subject to interference from all the newer technologies, it can't retry failed transmission, and generally has long since been eclipsed.