Building a power switch for Chromecast

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This Maker built a power switch for his Google Chromecast with the help of an ATtiny85, Bluetooth and Tasker.

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The Google Chromecast device is a neat media player that simply plugs into your TV to play media. One thing it doesn’t have, though, is a way to turn it off remotely. This might not be a problem for most people, but Ilias Giechaskel was using it as an input for a computer monitor which didn’t have a “remote off” function. It did, however, have the ability to go to sleep when no input was received, so turning off the Chromecast would serve a useful function in his setup.

Gichaskel decided to accomplish this task with “hardware that he already had available,” and opted for an ATtiny85 with its small physical footprint and number of I/O pins to control everything. He also used a Bluetooth chip for communication with his smartphone. The module receives an “on” or “off” command from the phone, then the ATtiny switches power to the Chromecast appropriately.

Originally, this setup meant that the user had to manually turn Bluetooth on, connect it to the Arduino, send the appropriate commands, then turn Bluetooth off. Doing all of this manually wasn’t what Giechaskel had in mind, so he wrote a Tasker plugin which takes care of this for him.

Of course, this isn’t Giechaskel’s only ATtiny85 hack. Be sure to check out how he replaced the guts of a bathroom scale using one!

Atmel-powered 1Sheeld (ATMega162) hits Kickstarter

Integreight’s 1Sheeld – powered by an ATmega162 MCU – is an easily configurable shield for Arduino boards. Essentially, 1Sheeld connects to a mobile Android app that allows users to take advantage of various smartphone features including the display, gyroscope, accelerometer, magnetometer, GSM, Wi-Fi and GPS.

“Our product consists of two parts. The first part is a shield that is physically connected to your Arduino board and acts as a wireless middle-man, piping data between Arduino and any Android smartphone via Bluetooth,” an Integreight rep wrote in a recent Kickstarter post.

“The second part is a software platform and app on Android smart phones that manages the communication between our shield and your smartphone and let your choose between different available shields. By doing that, you can use 1Sheeld as input or output from Arduino and make use of all of the sensors and peripherals already available on your Android smartphone.”

So what can you do with 1Sheeld? Well, according to Integreight, “the sky’s the limit.”

“You have a powerful Android smartphone that can be used to control your RC car, tweet when plants are thirsty and have fun playing with your friends. This is just a fraction of what you can actually do with 1Sheeld, [as the] possibilities are endless,” the Integreight rep explained.

“And you can hook it up with Tasker! Of course you can control your home with your phone and Arduino, like controlling heat, ventilation and air conditioning, yard watering, pet feeding and the list goes on. However, we’ve integrated a plugin to Tasker on Android, by linking Tasker to the hardware; you get a whole new experience of home automation. You can use any hardware event to trigger an action on the phone or vice-versa, you can use a phone event to trigger an action on the hardware.”

On the software side, 1Sheeld is running a custom version of the Firmata protocol which allows the microcontroller to quickly scan each pin of the Arduino and report any status change to the app.

“You can use this functionality out-of-the-box without the need for our library. There is another mode also which relies totally on the Serial peripheral of the Arduino (Pins 0,1),” said the rep. “Here our library comes in handy, we built a protocol above the Firmata protocol to send huge amount of data to a specific shield on our app, that allowed us to implement LCD, Twitter, Seven Segment – with only two pins from Arduino instead of taking a whole port.”

Aside from the embedded ATMega162, key technical specs include:

• Standard HC-06 Bluetooth adapter (Bluetooth 2.1)
• Range up to 30 feet
• 16 MHz operating frequency
• Communicates with Arduino via UART

Interested in learning more about the Atmel powered 1Sheeld? You can check out the project’s official page on Kickstarter.