Controlling Your Christmas Lights Without Ever Getting Off The Couch

December 18, 2011 by Mike Nathan 11 Comments

remote-xmas-tree-light-switch

14 year-old [Connor Smith] has been busy this holiday season, thinking up ways to improve the lighting situation at home.

A few weeks ago he put together this 3-channel light controller to toggle his parents’ external lights, incorporating an Arduino for control. The Arduino was used to switch the channels on and off at specified intervals in order to create a simple light show on the house’s exterior. Not satisfied with just a few strings of blinky lights, he took his controller back inside for some additional modifications.

He had grown tired of crawling behind the Christmas tree to plug and unplug it every day, and decided to make things easier on himself. He stripped the IR receiver out of an old VCR and interfaced it with the Arduino in his light controller using the IRremote library. After taking a bit of time to decode the values for two infrequently used buttons on his TV remote, he had himself a Christmas tree light switch that he could activate from across the room.

Check out the short video below to see his remote switch in action.

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Lamp Fading And Remote Control For The Lazy

November 29, 2011 by Mike Szczys 16 Comments

[Dmitry Grinberg] has to walk all the way across his bedroom to switch the lamp on and off. The drudgery of this finally became too much, so he built a remote control and added dimming for good measure. Above you can see the circuitry for the remote and the receiver, as well as the finished remote housed in what he calls a ‘Chinese Altoids tin’.

After the break you’ll find [Dmitry’s] demo video. The remote control is quite responsive, and the dimming has great resolution. That’s thanks to a power N-channel MOSFET which switches the AC with the help of a full wave rectifier. The PIC 12F617 that controls the MOSFET is powered separately, and [Dmitry] mentions that you must use a transformer and not a switch-mode power supply to avoid a fire. We’d like to know more about this, so leave a comment if you are able to explain further.

The remote and receiver communicate via Infrared. The protocol is operating with 38 kHz signals using an easily sourced receiver tuned to that frequency. [Dmitry] shares all the details about the encoding scheme that he uses. Recreating this communications pairing is a great way to test your understanding of this technique. But if you need a refresher, here’s a tutorial to push you in the right direction. Continue reading “Lamp Fading And Remote Control For The Lazy” →

Building Optical Flex Sensors

October 21, 2011 by Mike Szczys 12 Comments

[Joel] dug up this hack that he pulled off over ten years ago. It’s inspired by the Nintendo PowerGlove, and uses flex sensors to react to movements of your fingers. The interesting thing is, he built these optical flex sensors himself.

He likes to say that this is a ghetto fiber-optic setup. The inlaid diagram above gives you an idea of how the sensors work. An IR LED and infrared diode are positioned at either end of a piece of clear aquarium tubing. When the tube is flexed, the amount of light that makes it to the diode is diminished, a change that can be measured by a microcontroller. [Joel] found that he could increase the resolution of the sensor by adding something to the center of the tube, blocking the light when not straight. In this case he used pieces of scrap wire. The outside of the sensor was also wrapped in shrink tubing to keep ambient light from interfering with measurements.

He uses a trimpot to tune the sensors but we wonder how hard it would be to add a calibration algorithm to the firmware?

Prototyping A Bluetooth To IR Remote Control Translator

September 29, 2011 by Mike Szczys 14 Comments

[James] is one of those guys on a quest to control everything with one device. His tool of choice is an Android phone, which can do quite a lot right out of the box. But he was never satisfied with its lack of IR remote control abilities. He fixed that feature-gap by building a Bluetooth to Infrared translator.

The hardware he used for the prototype is quite simple. A cheap serial Bluetooth modem from eBay lets him connect to his phone. An Arduino board listens for data from the modem and converts incoming commands to flashes on an IR LED. Voila, he can control the tube with his phone.

We love the potential of this hack. The Bluetooth module runs from 3.3V, and reading serial data and flashing an LED is extremely simple. You should be able to use a small uC, say an ATtiny13, and a 3.3V regulator to miniaturize the module. We could see this plugging into the USB port on the back of a TV for power, with a wire extension to put the LED into position. The only shortfall is the inability to turn the TV on remotely when drawing power this way.

Remote codes aren’t particularly large to store either. So this would be pretty easy to extend to full control of all IR-compatible home entertainment devices. You just need a tool to discover the remote control codes.

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ATtiny Hacks: Infrared Guidance And Navigation

September 23, 2011 by Brian Benchoff 3 Comments

After [trandi] got his hands on a cheap R/C helicopter he realized the difficulties in actually flying a remote control helicopter. Instead of giving up, he decided to reverse-engineer the infrared protocol and then build a decoder around an ATtiny that would send commands to another microcontroller using a serial connection.

The remote’s communications protocol was decoded with the help of a Freeduino and an IR remote analysis sketch [trandi] found on the Arduino website. After importing the data into Gnuplot, there was enough data to write a sketch in Processing to visualize the infrared pulses.

After figuring out the protocol of his remote control, [trandi] built a tiny circuit to decrypt the IR commands and send them over a serial link to another microcontroller. The ATtiny45-based build doesn’t take up very much space on the perfboard making it very easy to mount on any robot of his choosing. He ended up connecting it to a Lego NTX brick allowing him to use the helicopter remote with any Lego build he can dream up.

[trandi] invested a lot of work around a cheap remote control; if the remote broke, all would be for naught. This was remedied with an IR beacon that replicates the function of the remote. The beacon is based on an ATtiny13 and can serve as a stand-alone beacon for autonomous robots or can accept serial commands from a computer. Not a bad build if you ask us.

Multitouch Tower Defense Uses Physical Towers

August 31, 2011 by Mike Szczys 4 Comments

If you’re tired of playing flash games with a mouse, perhaps you’ll draw inspiration from this project. Arthur built a multitouch interface that uses objects as part of the control scheme. In the image above you can see that the game board for a tower defense game is shown on the display. There is a frustum-shaped game piece resting on the surface. Just place that piece where you want to build your next tower, and then select the tower type from the list.

The controller itself is pretty straight-forward. The surface is a piece of acrylic topped with some light diffusing material. A projector shines through another acrylic window on the side of the unit, reflecting on a mirror positioned at a 45 degree angle. As for the multitouch detection, the hardware uses a series of UV LEDs along with a modified PS3 eye camera. [Arthur] chose the reacTIVision software package to process the input from the camera. Check out a couple of videos after the break to see the hardware, and some game play.

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Mini IR Theremin

July 8, 2011 by Brian Benchoff 6 Comments

[Chris] at PyroElectro sent in a great 8-part write-up of a miniature infrared theremin.

The theremin is based on a PIC microcontroller and an infrared distance sensor. The build log goes through the theory of operations for the IR sensor and tone generation. [Chris] definitely does a great job showing the math that went into the design.

Although this project isn’t a true theremin because it operates on light like a few other projects we’ve covered in the past, it’s easier to play because of the hard-coded notes. The build does show some promise though – he could likely expand it to use more accurate ultrasonic sensors or use, “two proximity sensors, one for treble and one for bass like an accordion.”

The theremin is usually played with both hands providing a continuous pitch and volume. This project features hard-coded, discrete notes, so we’re wondering about the possibility of implementing MIDI on this IR theremin. The original MIDIbox was based on the same microcontroller as this project, so it’s definitely a possibility.

Check out the video of the theremin in action below.

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