Seeing plant health in infrared

aerial

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.

Adding night vision to the Raspberry Pi camera

IR

After months of promises, the Raspberry Pi camera is finally heading out to hackers and makers across the world. Of course the first build with the Pi cam to grace the pages of Hackaday would be removing the IR filter, and it just so happens [Gary] and his crew at the Reading hackerspace are the first to do just that.

As [Gary] shows in his video, the process of removing the Pi cam’s IR filter is extremely fiddly.  Getting the filter out of the camera involves removing the sensor, gently cutting it open with a scalpel, and finally gluing the whole thing back together with a tiny bit of superglue. Not for the faint of heart, and certainly not for anyone without a halfway decent bench microscope.

If you’re looking for a Raspberry Pi-powered security camera, game camera, or something for an astronomy application, this is the way to make it happen. You might want to be careful when removing the IR filter; [Gary] broke one camera on their first attempt. They got it to work, though, and the picture quality looks pretty good, as seen in the videos below.

[Read more...]

Infra is a television made of Infrared pixels

ir-television-using-625-tv-remotes

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.

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An absurdly clever thermal imaging camera

clever

Thermal imaging cameras, cameras able to measure the temperature of an object while taking a picture, are amazingly expensive. For the price of a new car, you can pick up one of these infrared cameras and check out where the drafts are in your house. [Max Justicz] thought he could do better than even professional-level thermal imaging cameras and came up with an absurdly clever DIY infrared camera.

While thermal imaging cameras – even inexpensive homebrew ones – have an infrared sensor that works a lot like a camera CCD, there is a cheaper alternative. Non-contact infrared thermometers can be had for $20, the only downside being they measure a single point and not multiple areas like their more expensive brethren. [Max] had the idea of using one of these thermometers along with a few RGB LEDs to paint different colors of light around a scene in response to the temperature detected by an infrared thermometer sensor.

To turn his idea into a usable tool, [Max] picked up an LED flashlight and saved the existing LED array for another day. After stuffing the guts of the flashlight with a few RGB LEDs, he added the infrared thermometer sensor and an Arduino to change the color of the LED in response to the temperature given by the sensor.

After that, it’s a simple matter of light painting. [Max] took a camera, left the shutter open, and used his RGB thermometer flashlight to paint a scene with multicolor LEDs representing the temperature sensed by the infrared thermometer. It’s an amazingly clever hack, and an implementation so simple we’re surprised we haven’t seen before.

Autonomous helicopter works like a Wii remote

autonomous-ir-helicopter

[Jack Crossfire] took one of those inexpensive indoor helicopters and made it autonomous. He didn’t replace the hardware used for the helicopter, but augmented it and patched into the remote control to make a base station.

The position feedback is provided in much the same way that the Wii remote is used as a pointing device. On the gaming console there is a bar that goes under the TV with two IR LEDs in it. This is monitored by an IR camera in the Wii remote and used to calculate where you’re pointing the thing. [Jack's] auto-pilot system uses two Logitech webcams with IR filters over the sensors. You can see them mounted on the horizontal bar in the cutout above. The helicopter itself has an IR LED added to it that is always on. The base station follows this beacon by moving the cameras with a pair of servo motors, calculating position and using it when sending commands to the remote control’s PCB.

Don’t miss the demo video of the rig after the break.

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Beefing up a smoke alarm system with video, temperature, and connectivity

Here’s a little smoke detector hack which [Ivan] has been working on. He wanted to extend the functionality of a standard detector and we’re happy to see that he’s doing it with as little alteration to the original equipment as possible (this is a life-saving device after all). He sent all the build images for the project to our tips line. You’ll find the assembly photos and schematic in the gallery after the break.

As you can see his entry point is the piezo element which generates the shrill sound when smoke as been detected. He connected this to his own hardware using an optoisolator. This allows him to monitor the state of the smoke alarm on his server. It then takes over, providing a webpage that display’s the board’s temperature sensor value and streams video from an infrared camera.

Of course this is of limited value. We’ve always made sure that our home was equipped with smoke detectors but the only time they’ve ever gone off was from normal cooking smoke or after an extremely steamy shower. But still, it’s a fun project to learn from and we’ve actually got several of the older 9V battery type of detectors sitting in our junk bin.

[Read more...]

Dimming the living room lights using your TV remote

As part of a complete home theater setup [Andy] wanted to be able to control the lights from his couch. He started thinking about the best way to do this when he realized that his TV remote has buttons on it which he never uses. Those controls are meant for other components made by the same manufacturer as the TV. Since he doesn’t have that equipment on hand, he built his own IR receiver to switch the lights with those unused buttons.

He monitors and IR receiver using an AVR microcontroller. It is powered from mains via the guts from a wall wart included in the build. Also rolled into the project is a solid state relay capable of switching the mains feed to the light circuit. [Andy] mentions that going with a solid state part mean you don’t get that clicking associated with a mechanical relay. An electrical box extension was used to give him more room for mounting the IR receiver and housing his DIY circuit board.

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