Infrared Control For Appliances

July 7, 2011 by Brian Benchoff 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 Mike Szczys 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 Jeremy Cook 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” →

Electronic Bird House Monitoring Goes A Few Steps Further

May 31, 2011 by Mike Szczys 7 Comments

[Stephen Albers] offers his avian friends a lot of extras with this electronically monitored bird house. This will not only give you a look at what’s going on inside, but provide a source for several other bits of data as well.

First off, a camera has been mounted to the underside of the roof. This looks down on the nesting area and features night vision so that you can peek in any time day or night. He used a WiFi webcam that operates separately from the other electronics.

With the remainder of the setup he is able to harvest temperature and humidity data inside, temperature outside, force on the bottom of the house (although this turned out to be less useful than anticipated), and a in-and-out count for the doorway provided by an IR transmitter/receiver pair.

This offers quite a bit more than the last bird house project we saw. That one also left a lot to be desired as far as protecting the electronics. [Stephen] didn’t skip on that kind of protection. Most of the electronics are housed in an acrylic chamber in the base of the house. The sensors find themselves nestled in plastic enclosures, although some work needs to be done to ensure that the temperature and humidity sensors will still function correctly with this setup.

DSLR Infrared Camera Conversion

April 22, 2011 by Mike Nathan 17 Comments

ir_conversion

[Jerry] recently got a shiny new DSLR camera and was looking to do something with the old Pentax DSLR it replaced. Having performed a few point and shoot IR conversions in the past, he was pretty confident he could tackle this conversion without too much trouble.

He located the service manual for the camera and got busy taking it apart. He had to desolder the main board to get to the CCD block, where the sensor, IR cut filter, and the shake reduction motors are all located. The IR cut filter was pried off without too much trouble as it is only secured with a clip and an adhesive foam gasket.

Once things were disassembled, the real work began. He had a little trouble cutting the IR filter he purchased, so it took a little bit of elbow grease to get things exactly the way he wanted. Once he got the filter in place, he carefully re-mounted the sensor block to ensure that it was set at the proper height.

Once things were fully reassembled, he tried taking a few test shots, but found that there were some focus issues due to the IR filter being thicker than the original IR cut filter. A few manual tweaks in the camera’s debug menu and he was in business.

Be sure to check out his photo stream to take a look at some of the pictures he snapped with his new IR camera.

The Basics Of Building A Multitouch Table

April 16, 2011 by Mike Szczys 15 Comments

Here is a bare-bones multitouch table setup. We looked in on [Seth Sandler’s] multitouch work a few years ago when he completed the MTmini build. He’s scaling up the size a bit with the MTbiggie, and showing you how easy it is to put together. The demo rig seen above is just a couple of chairs, a sheet of acrylic, a mirror, a projector, a computer, and a diy infrared webcam.

The rig uses ambient infrared light to detect the outlines of your fingers when they touch the acrylic surface. A webcam with an exposed camera film filter feeds an image of the infrared light received below the surface to the computer. The incoming video is processed using Community Core Vision, where each individual point is isolated and mapped. Once the data is available the sky’s the limit on what you can develop. [Seth’s] demo packages include a mouse driver, some physics applications, an Angry Birds implementation, and a few others. See for yourself in the video after the break.

Continue reading “The Basics Of Building A Multitouch Table” →

IPhone-based Universal IR Remote

March 1, 2011 by Mike Nathan 29 Comments

If you have a reasonable home theater setup in your living room, odds are you have up to half a dozen remotes sitting around. Short of trying to get your cable receiver’s remote to control everything or laying down some cash for a Harmony remote, what’s a hacker to do?

[Andrey] decided he wanted to use his iPhone as a universal IR remote, but he didn’t want to pay very much to do so. Instead of buying a dongle at the store, he soldered some IR LEDs to an old headphone plug, creating a mini IR dongle to control his equipment. After studying IR signaling a bit, he got to work encoding IR remote commands into wav files using Python. The files are then played on his iPhone, allowing him to submit certain commands to his TV set.

Unfortunately, the process of manually converting IR codes to audio files doesn’t quite seem like the most efficient way of doing things. There are other IR dongles currently on the market that utilize the headphone jack, most of which provide pretty robust software for free. These might make a good alternative to manually creating audio files for each IR command. We honestly haven’t seen any teardowns of these retail IR dongles posted online, but it would be interesting to see how they compare to what [Andrey] has put together.