Seeing plant health in infrared

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Since the 70s, NASA, NOAA, and the USGS have been operating a series of satellites designed to look at vegetation health around the world. These satellites, going under the name Landsat, use specialized camera filters that look at light reflecting off chlorophyll to gauge the health of forests, plains, oceans, and even farms. It’s all very interesting technology, and a few very cool people want to put one of these near infrared cameras in the hands of everyone.

The basic idea behind gauging the health of plants from orbit, or the Normalized Difference Vegetation Index, is actually pretty simple: absorb red and blue light (thus our verdant forests), and reflect nearly all infrared light. By removing the IR filter from a digital camera and adding a ‘superblue’ filter, the NDVI can be calculated with just a little bit of image processing.

The folks behind this have put up a Kickstarter with rewards including a modified webcam, a custom point and shoot camera, and a very low-cost source of one of these superblue filters. Just the thing to see how your garden grows or how efficiently you can kill a houseplant.

Chromebook hack controls your television

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[Michael Kohn] only accomplished about half of what he set out to, but we still think his TV channel switcher from a Chromebook turned out nicely. When starting the project he wanted to include a grid of listing so that he could choose a specific program, but decided that scraping the data was too much work for this go-round.

The Chromebook doesn’t include an IR transmitter so he built one using an MSP430 chip. He had previously built a little transmitter around an AVR chip and was surprised to find that the internal oscillator on that was quite a bit more accurate than on the MSP430. Timing is everything with the Manchester encoded signals used for IR remote controls so he used his oscilloscope to tune the DCO as accurately as possible.

The app shown on the screen was written in Javascript. Google published some example code on using RS232 with the computer; [Michael] used this resource to provide communications between the computer and the microcontroller.

[Read more...]

IR Based Augmented Reality

ARUCI

For a final design project, [Frank] and his group took on an augmented reality project. The goal was to make objects interactively controllable by pointing a smartphone at them. Their solution was Augmented Reality Universal Controller and Identifier (ARUCI).

The system locates controllable objects by sensing IR beacons that contain identifiers for each object. The IR is received by a Wiimote sensor, which has been integrated into a custom PCB. This board sits in a 3D printed enclosure, and mounts to the back of a smartphone. The electronics are powered by tapping off of the phone’s battery.

Commands are sent to devices using a custom 2.4 GHz protocol which was implemented using the ATmega128RFA1. Each device has another ATmega to receive the signal and control the real world object. In their demo, the group shows the system controlling devices including a TV, a radio, and an RC car.

The system provides an interesting way to interact with objects, and the hardware integration is quite impressive. After the break, watch [Frank] give a demo.

[Read more...]

Eloquent universal receiver for your home entertainment equipment

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We’re really starting to enjoy the home entertainment control hacks which use a universal receiver to act on commands from any remote. This one is especially interesting as it uses a single remote to control the system but rolls in lots of extras.

Looking at the receiver itself the white plastic dome of the PIR sensor should raise an eyebrow. Since the cable box takes a while to turn on [Ivan] included the motion sensor to switch that component on when you walk into the room. This way it’ll be ready to go by the time you sit down. It does this by sending IR signals from the PIC32 dev board. Of course the board has its own receiver to listen for the remote control commands. The remote buttons have been mapped a bit differently than originally intended. You can see in the diagram above that the normal VCR/DVD/DVR buttons have been set to control the room’s LED strips. There’s even a power consumption monitor rolled into the project. All of these features are demonstrated in the clip after the break.

This is a nearly perfect base setup. But we’d love to see it with a web interface at some point in the future.

[Read more...]

A real thermal imaging camera for $300

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If you want to check your house for hot air leaks, take pictures of the heat coming off a rack of equipment, or just chase the most dangerous animal, [Arnie], through the jungles of central america, a thermal imaging camera is your friend. These devices normally cost a few thousand dollars, but the team behind the Mu Thermal Camera managed to get the price down to about $300.

The basic idea behind the Mu Thermal Camera is overlaying the output of an infrared thermopile – basically, an infrared camera – on top of the video feed of a smart phone’s camera. This is an approach we’ve seen before and something that has even been turned into a successful Kickstarter. These previous incarnations suffered from terrible resolution, though; just 16×4 pixels for the infrared camera. The Mu thermal camera, on the other hand, has 160×120 pixels of resolution. That’s the same resolution as this $2500 Fluke IR camera. After the indiegogo campaign is over, the Mu camera will eventually sell for $325.

We have no idea how the folks behind the Mu camera were able to create a thermal imaging with such exceptional resolution at this price point. The good news is the team will be open sourcing the Mu camera after their indiegogo run is over. W’e’d love to see those docs now, if only to figure out how a thousand dollars of infrared sensor is crammed into a $300 device.

Pair of musical hacks use sensor arrays as keyboards

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This pair of musical keyboard hacks both use light to detect inputs. The pair of tips came in on the same day, which sparks talk of consipiracy theory here at Hackaday. Something in the weather must influence what types of projects people take on because we frequently see trends like this one. Video of both projects is embedded after the jump.

On the left is a light-sensitive keyboard which [Kaziem] is showing off. In this image he’s rolling a marble around on the surface. As it passes over the Cadmium Sulfide sensors (which are arranged in the pattern of white and black keys from a piano keyboard) the instrument plays pitches based on the changing light levels. [Thanks Michael via Make]

To the right is [Lex's] proximity sensor keyboard. It uses a half-dozen Infrared proximity sensor which pick up reflected light. He calls it a ‘quantised theremin’ and after seeing it in action we understand why. The overclocked Raspberry Pi playing the tones reacts differently based on distance from the keyboard itself, and hand alignment with the different sensors.

[Read more...]

Infra is a television made of Infrared pixels

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This television is perfect except for its low resolution and the fact that it can’t be seen by the naked eye. [Chris Shen's] art installation, Infra, uses 625 television remotes as pixels for a TV screen. There’s a little bit of insight to be gained from the details which [Chris] shared with EMSL.

The remote controls were all throw-aways. Even if there are problems with the buttons, battery connectors, or cases, chances are the IR led in each was still functional. So [Chris] patched into them using about 500 meters of speaker wire.

Why 625 pixel? Because that’s how many LEDs the Peggy board can handle. We’ve seen this open source LED board driving video in other projects. Here it’s been connected to each remote using Molex connectors. Each of the headers has the same pitch as a through-hole 5mm LED. The entire board was filled with them, and a mating crimp connector terminates the end of the wire coming out of each remote. This makes setup quite easy as the remotes don’t have to be installed in any particular order as long as the physical location matches Peggy’s grid.

You can get a glimpse of the piece playing video in the clip after the break.

[Read more...]

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