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.

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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.

Fingertip Heart Rate Monitor

February 17, 2011 by Chris Nelson 12 Comments

[Embedded lab] has a nice tutorial on building your own heart rate monitor. The monitor works by shining infrared light into the fingertip and looking at the changes in the reflected infrared signal caused by a heartbeat. The IR detector produces a very small AC signal so a couple of op-amps are used to filter and amplify the signal. The output of the filter circuit is then read in by a PIC16F628A, which counts the beats and displays it on a seven segment display. This might be a good project to try if you’ve got your microcontrollers down and you are looking to learn some analog electronics. Its noted at the end that the two main problems with building a circuit like this are going to be cross talk and adjusting the filters. The infrared diode and receiver should be close to each other to allow maximum reflection but you also need to make sure that you don’t allow the emitter to shine directly into the detector because the reflected light will be drowned out by the bright emitter.

[via make]

38 KHz IR Communications Tutorial

February 16, 2011 by Mike Szczys 14 Comments

Learning about how infrared remote controls work is a great way to expand your electronics knowledge. That’s because this technology is invisible to our eye, and happening faster than we can comprehend without help from test equipment. This tutorial over at Pyroelectro talks about the theory behind how the data is transferred and shows you how to build a couple of circuits to experiment with and communicate through infrared light transmissions.

Instead of going with an IR receiver module you’ll build your own using a photo-transistor and an operational amplifier. The Opamp is used to amplify and invert the signal picked up from the IR transmission of a common home entertainment remote control. From there the digital signal is read by a PIC 18F452 microcontroller for processing. But if you want to use a different microcontroller there’s still more than enough usable information to get you across the finish line.

Long-range Laser Night-vision

February 16, 2011 by Mike Szczys 24 Comments

[Oneironaut] is back at it again, churning out yet another great hack in this long-distance night vision build. This isn’t the first time we’ve seen him build a night vision device, you may remember the monocle he put together using the view finder from an old camcorder. This time around he’ll give you look at distant object by using a laser instead of LEDs. He pulled an IR laser diode out of an old CD burner, then used a lens to spread out the dot in order to illuminate a larger area. A standard rifle scope is used as the optics, along with a security camera which can detect the infrared light. As always, he’s done a fantastic job with the images and the write-up. You’ll find his overview video embedded after the break.

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