Cheap infrared photography

2011-07-13

Infrared panorama

After a few unsuccesful attempts to modify an old camera for infrared photography, I modified one of the two cheap cameras ($40 USD) that I’ve got some time ago. Those cameras are cheap and tiny, usually came embedded inside pens or keychains.

Due to their size it is quite common to modify or attach those cameras to a variety of places; think, for example, to attach the camera to ballons for aerial video, radio controlled planes, helicopters or other vehicules, or seal it inside an empty bottle for underwater photography, just to mention some random uses that came to mind.

It was on a RC forum thread where I first read about removing the infrared filter in those cameras, along with a lot of useful information.

Microcamera disassembledMicrocamera IR filter detached

The infrared filter is a thin circular element located on the rear of the lens. It was needed to carefully remove the glue around lens thread, but the overall process of removing the filter was much easier than expected, specially in comparison with any other camera I’ve tried before. Colors are distorted without its infrared filter, but in return it recieves more light, sensitivity improves, and it can be used as a “night vision” camera.

Once assembled and refocused, the first test was quite simple: let’s see the infrared light of a remote controller. The modified camera captures the light, while it is invisible to the other (as our eyes).

Infrared remote seen by 2 cameras

Next step was to block the entire visible spectrum, in order to capture infrared exclusively; that is, the inverse effect than the one performed by camera’s internal infrared block filter. I’ve used a filter designed for infrared photography, a piece of glass that looks black and completely opaque to our eyes, but not to the modified camera which can see through it.

Visible light filter seen by 2 cameras

The quality of the pictures straight from the camera is far from great. I’ve done the following:

Infrared panorama before color modification

The original has a red or pink tone because the filter allows some deep red to pass through it. A deeper infrared filter should produce black and white images and only purely invisible light would be recorded, supposing that camera’s automatic white balance won’t become crazy, this is something I want to test later.

A common effect for infrared photography is to switch red and blue channels (if the filter allows some red to pass), or just modify color channels and give a fake set of new colors to the image.

Infrared panorama

Infrared photos tend to look surrealistic. We normally can’t see the infrared light reflected by things, hence the strange appearance. Sky becomes dark (blue is easily removed by the filter), clouds are bright and prominent; green trees and grass reflect a lot of infrared light and become very bright, while dry plants remain darker.

Filed under: Hardware, Photography

Alone under LED illumination ;)

2011-04-23

Admitedly, I’ve always been interested in LEDs. High intensity LEDs across the entire visible spectrum are easily available nowadays, so providing a science fiction spaceship look to the house was tempting enough :)

LED decorative lights10W White LED with heat sink

Still trying several things, but these are a few conclusions so far:

RGB LEDs (composed of three smaller LEDs) can emit light in any colour by mixing the three primary, and theoretically one could build a wide set of lighting effects with them. The big limitation is in the controllers, though. Commercially available controllers (also known as dimmers) for RGB LEDs are cheap but usually quite boring, in the sense that they offer no more than fixed colours and very limited blink or shading effects to choose from. Not a big surprise. It would be much more fun to have programmable controllers, or at least a wider set of options built-in.

A very interesting additional possibility would be to attach sensors or timers, and fade, switch colours or adjust intensity depending of time of day, day of week, outer temperature, music played in the room, or any other event. I’m sure that many people reading this are thinking about the Arduino, and me too.

Some sort of computer interface will allow to reprogram or control illumination parameters through a network connected tablet. And what about a webcam? We could detect motion events within a room and make the LEDs react to them… So, once again, it seems unavoidable to construct something. Please feel free to drop a comment if you know a better RGB controller already available, something hackable, or have an idea for making one.

On the other side, very succesful results were achived using “warm white” (around 3500K maybe) LEDs for general illumination. The color rendering index seems to be poor, though it shouldn’t be a problem for ordinary usage.

A floor lamp was modified to hold 3 10W LEDs and heat sinks inside. Actually, each LED appear to be internally composed of 9 smaller LEDs packed under the enclosure. They are OK too, but I think I prefer large arrays of lower intensity LEDs, seems more practical and they don’t need those huge heat sinks. Those 3 LEDs alone give a perceived light that’s maybe comparable to 150W halogen lamp (imprecise measurements done with a basic lux meter). It could be better if they weren’t running under an electric current below the specified maximum, because I’m not completely confident about the heat sink capabilities. The actual consumed power depends very much on the efficiency on the power supply plus power loss in resistors or intensity limiting circuits, but very efficient overall.

Filed under: Hardware

Photos of a Freerunner

2009-06-22

Photos of an Openmoko Freerunner mobile phone (not new, took them last year). Debian installed. The capacitor soldered within its micro SD pins is present on modern hardware revisions to solve a problem with the GPS.

Linux boot messages on FreerunnerOpening a FreerunnerCapacitor in microSD socket

Photos taken by me and, as usual, published under a Creative Commons Attribution 3.0 license.

Filed under: Embedded, Hardware, Photography

SmartQ5 MID

2009-05-08

The SmartQ5 MID is an ARM tablet device made by a chinese company. Based on S3C6410 processor, it can run Linux, modified Qi and U-Boot bootloaders, and low cost. An interesting platform for hacking. I could not resist the temptation to open it and take some photos of its inner beauty.

SmartQ5 MIDOpening a SmartQ5Removing screws to access the PCBSmartQ5 PCBSmartQ5 PCBSmartQ5 PCB with battery attached

Photos taken by me and, as usual, published under a Creative Commons Attribution 3.0 license.

Filed under: Embedded, Hardware, Photography

Alone in the Light


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Unless otherwise stated, articles and their accompanying pictures are licensed under a Creative Commons Attribution 3.0 Spain License.

Roberto Gordo Saez

roberto@zenvoid.org

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