Adding Ethernet control for a 5.1 speaker set

[HuB’s] set of 5.1 surround sound speakers was gobbling up a bunch of electricity when in standby as evidenced by the 50 Hz hum coming from the sub-woofer and the burning hot heat sink on the power supply. He wanted to add a way to automatically control the systems and offer the new feature of disconnecting the power from the mains.

The first part was not too hard, although he used a roundabout method of prototyping. He planned to use the IR receiver on the speakers to control them. At the time, [HuB] didn’t have an oscilloscope on hand that he could use to capture the IR protocol so he ended up using Audacity (the open source audio editing suite) to capture signals connected to the input of a sound card. He used this to establish the timing and encoding that he needed for all eight buttons on the original remote control.

Next, he grabbed a board that he built using an ATmega168 and an ENC28J60 Ethernet chip. This allows you to send commands via the Internet which are then translated into the appropriate IR signals to control the speakers and a few other devices in the room. The last piece of the puzzle was to wrap an RF controlled outlet into the project with lets him cut mains power to the speakers when not in use. You can see the video demonstration embedded after the break.

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Reverse engineering radio controlled outlets

[Chr] picked up a pack of remote control outlets in order to reverse engineer them and build control into his own projects. These can be plugged into outlets around your house and a relay inside each module will switch whatever device is plugged into it after receiving a command from the remote. Once he cracked open the control housing it was easy to find the data line for the RF module which was on its own board. He used a logic analyzer to capture data from various button presses and then spent some time deciphering the communication protocol. He used what he learned to roll the module and code into an interface box where an ATmega8 connects via USB and passes commands from a computer to the RF board. Now he’s added home automation via a computer quite inexpensively. After the break you can watch a clip of the outlets switched using a smartphone.

So why not just patch into the buttons on the remote? Well, this same project was attempted at our local hackerspace earlier this month and the buttons don’t just pull a pin to ground. They use tri-state logic and are arranged into a matrix that is a lot harder to mimic (if not impossible) with a microcontroller. Analyzing the communications going into the RF module is definitely the less labor-intensive of the two approaches.

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SPRIME controlled AC outlets

Reader [Tim Upthegrove] sent in a novel take on powering and monitoring AC outlets and devices called SPRIME, or Simple Powerline Remote Interactive Monitor and Enforcer. Compared to previous hacks, such as 120v switching or Quick cheap remote outlets, that only turned an outlet on or off; SPRIME allows not only control over outlets via the internet, but also power usage of devices currently plugged in.

We really liked their idea of giving power companies access to SPRIME outlets to reduce power consumption during peak hours, but sadly we don’t see it being implemented in homes any time soon. Catch a video of SPRIME after the rift.

[Thanks Chris McClanahan and Jeff Starker for the project, and deyjavont for pointing out our silly mistakes]

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