infrared

166 Articles

Prototyping A Bluetooth To IR Remote Control Translator

September 29, 2011 by 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 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 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 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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Infrared Control For Appliances

July 7, 2011 by 10 Comments

[RB] at Embedded Lab sent in a great guide on how to control appliances with a remote control using a really clever implementation of a decade counter and IR receiver.

The build itself is very simple – just a relay connected to mains power and a handful of resistors and transistors. The device is controlled with a decade counter and an infrared module usually found tucked away in the bezel of a TV.

When everything is plugged in, the first pulse from the remote switches the relay on, providing power to the outlet. When a second pulse is received, the reset pin on the decade counter is activated, setting the device back to its original off state. It’s a pretty clever build, and could be built with parts lying around the bench.

The project is powered through wall power with the help of a transformer and a 7805 regulator, but we think the size could be reduced with a pass-through power enclosure – the circuit certainly is small enough. In all, a very nice, low component count build.

Measuring RPM With Reflective Sensors

June 25, 2011 by 7 Comments

[Arao] wanted to measure the RPM of a spinning wheel using parts that he could scavenge from his junk box. A bit of thought led him to build a reflective sensor which can measure the spinning of a wheel (translated).

He got his hands on an infrared phototransistor which had been used as part of the remote control for some consumer electronics. Snooping around with his multimeter helped him establish the pin out of the device. By positioning an IR LED inside of a shroud, yet adjacent to the phototransistor, he can measure the intensity of the LED’s light as it is reflected off of nearby surfaces. The pulley seen above has a piece of electrical tape on it. When this passes by the LED, less of the infrared light is reflected and the drop in intensity is picked up by the phototransistor. [Arao] made the system rock-solid by rolling an LM358 op-amp into the circuit. He’s posted the schematic as well as some screen shots from an oscilloscope during testing.

The Infrared Graduation Cap

June 19, 2011 by 31 Comments

It’s graduation time for many high schoolers, and while many students would love to decorate their caps, administration generally looks down upon this practice. [Victor], however, thought of a way around this.

The human eye cannot see infrared light, but camcorders generally can. Putting these two concepts together with a couple of infrared LEDs, [Victor] was able to make a cap that displayed his decoration in everyone’s “digital memory”, but wouldn’t be detected until the video of the offense was displayed. Hopefully by the time the prank is detected, [Victor] will have successfully graduated and presumably gone on to other pursuits.

An ATmega 168 controls this hat to display his message, “Congratulations Class of 2011,” in Morse code. What a creative use of both old and new technology to pull off an awesome graduation prank. Be sure to check out the video after the break to see how everything was put together. Continue reading “The Infrared Graduation Cap” →