Home Automation Tips & Tricks

You can never know too many tips and tricks for programming and installing home automation.

Fred Harding · November 10, 2009

Automating components and commands is one of the fun things we do in this business. I’m referring to a situation where you turn on device A, and other things happen without any additional actions required by the user.

One automation scenario that many are familiar with involves HDMI. One of the characteristics of this interconnect is a communications protocol that switches a display on and selects an input based on powering up a source such as a Blu-ray player.

Customers who have a very simple system may enjoy this feature, but if you are working with multiple displays and sources in a matrixed application, trouble will happen. It is, however, a feature you can defeat.

Most automation tricks can be initiated by a remote control sequence of commands called a macro. A macro essentially requires a button press to send multiple button presses’ worth of commands out. I push “watch TV,” and the display, A/V receiver, satellite receiver all power up, appropriate inputs are selected, a favorite channel is entered, and the remote finishes up at a page with TV controls displayed.

Projectors & Screens

A logical automation that many installers deploy involves projectors and motorized screens. If the projector is turned on, then the screen should be deployed. The opposite situation is true as well. Many projectors offer triggered outlets that supply a small voltage that appears when the power is on; simply run a wire over to the trigger input on the screen and the system works as required. Unfortunately, many projector manufacturers are leaving the trigger output off of their devices. A solution is to put a current-sensing device on the projector.

Current-sensing devices are available from a number of manufacturers, including Niles and Xantech. These devices plug directly into the electrical outlet, and the projector (or other component) plugs into it. When the device senses a difference in the electrical current being used, it typically puts out a 12-volt DC signal.

Sharing Speakers with 2 Sources

Another popular automation technique is to share a pair of speakers with two sources. A typical application might involve a surround-sound receiver and a whole-house audio system, where the surround speakers may be asked to serve both sources. A simple A/B switch to select between sources could be deployed, but a much more elegant option is to use a voltage-activated A/B switch.

When performing automation of any type, you’ll want to think about what setting might be considered the default situation, and which might be considered the priority. In other words, when an action occurs, you always want that to take priority.

In our surround speaker application, for example, it’s important to remember that surround sound is not always present. You’ll want to have those speakers available whenever a surround signal is present, and by putting a voltage-activated A/B switch in place and setting the surround receiver as the priority while the whole-house audio is the default, the system will function perfectly every time.

If the surround receiver doesn’t have a trigger or power outlet, you can deploy a current-sensing device to complete the automation.

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  About the Author

Fred Harding is in sales and technical support at Capitol Sales, a full service distributor of electronic installation hardware. He is a frequent contributor to CE Pro, writing hands-on product reviews and technical tips. Have a suggestion or a topic you want to read more about? Email Fred at

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  Article Topics

News · Blu-ray · Fred Harding · HDMI · Home Automation · Niles · Projectors · All Topics
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