THP Entry: A Digital Large Format Camera

Click to embiggen. It's seriously worth it.

Click to embiggen. It’s seriously worth it.

After 20 or so years of development, digital cameras may soon be superior to film in almost every way, but there are a few niches where film cameras reign supreme. Large format cameras, for example, are able to produce amazing images, but short of renting one for thousands of dollars a day, you’ll probably never get your hands on one. For his entry to The Hackaday Prize, [Jimmy.c..alzen] decided to build digital large format camera, using an interesting device you don’t see used very often these days – a linear CCD.

[Jimmy]‘s camera is built around a TAOS TS1412S, a linear CCD that is able to capture a line of light 1536 pixels across. The analog values are clocked out from this chip in sequence, going straight into an Arduino Due for processing, saving, and displaying on a small screen.

Inside the camera, the sensor is on a pair of rails and driven across the focal plane with the help of a stepper motor. The effect is something like the flatbed scanner to camera conversions we’ve seen in the past, but [Jimmy] is able to adjust the exposure of the camera simply by changing the integration time of the sensor. He can also change the delay between scanning each column of pixels, making for some really cool long-exposure photography techniques; one side of an image could be captured at noon, while the other side could be from a beautiful sunset. That’s something you just can’t do otherwise without significant digital manipulation outside the camera.


SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

Taking Pictures with a DRAM Chip

 

DRAM Image

This picture was taken by using a DRAM chip as an image sensor (translated). A decapped 64k DRAM chip was combined with optics that could focus an image onto the die. By reading data out of the DRAM, the image could be constructed.

DRAM is the type of RAM you find on the RAM cards inserted into your motherboard. It consists of a massive array of capacitors and transistors. Each bit requires one transistor and one capacitor, which is quite efficient. The downside is that the memory needs to be refreshed periodically to prevent the capacitors from discharging.

Exposing the capacitor to light causes it to discharge faster. Once it has discharged past a certain threshold, the bit will flip from one to zero. To take a picture, ones are written to every bit in the DRAM array. By timing how long it takes a bit to flip from one to zero, the amount of light exposure can be determined. Since the DRAM is laid out in an array, each bit can be treated as a pixel to reconstruct the image.

Sure, modern CCDs are better, cheaper, and faster, but this hack is a neat way to totally re-purpose a chip. There’s even Turbo Pascal source if you’d like to recreate the project.

Thanks to [svofski] for the tip.

Swapping the sensor in a DSLR

OLYMPUS DIGITAL CAMERA

To take a color image, modern digicams have something called a Bayer pattern – small red green and blue filters, one color for each pixel – that drastically reduce the resolution if all you’re doing is taking black and white pictures. [Lasse] is an astrophotographer, and doesn’t exactly need color pictures, so he decided to swap the color sensor in his camera with a monochrome CCD.

Most DSLRs have CCD sensors on strange surface mount packages or put everything on flex PCBs. [Lasse]‘s Olympus E-500, though, features an 8 Megapixel CCD on a ceramic DIP that is actually fairly easy to remove given the right tools and just a little bit of mechanical encouragement.

After putting in a new monochrome CCD, [Lasse] had a much more sensitive sensor in his camera, and processing the RAW files off the camera gives him a great improvement for his astrophotography.

This isn’t [Lasse]‘s first adventure in tearing apart DSLRs for astrophotography. Earlier, he uncovered the secrets of the Four Thirds lens format with a logic analyzer, making his Olympus camera a wonderful tool for looking into the heavens.

Canon A70 CCD replacement/repair

Looking for an underwater camera setup, [Imsolidstate] picked up a Canon A70 and a Canon water-tight housing on eBay for around $45. Unfortunately the camera arrived with a non-functioning CCD. Another trip to the online auction site landed him a replacement CCD which he set about installing.

We have this exact model of camera with a cracked LCD display. Being that we like to hack around on things we’ve pulled it apart in order to replace the screen and believe us, there’s no extra room inside that thing. The video after the break shows the teardown, and you can see what a pain it is to get the unit apart. That process in only eclipsed in difficulty by the reassembly itself.

In the end it wasn’t a problem with the CCD itself, but with the connector on the PCB that received the flat cable. It wasn’t holding the contacts tight, but [Imsolidstate] fixed that with a strategically placed piece of foam.

[Read more...]

Converting a scanner into a touchscreen

[Sprite_TM] was cleaning up his hacking workbench when he came across an all-in-one device that had seen better days. After a bit of consideration he decided to tear down the scanner portion of the device and ended up turning it into a multi-touch display.

The scanner relies on a long PCB with a line CCD sensor. This sensor is read in a similar way that information is passed along a shift register. Tell it to take a reading, and then start a clock signal to pulse out each analog value from the pixels of the sensor. In order to scan color images it uses multicolored LEDs to take different readings under different illumination.

[Sprite_TM] takes advantage of this functionality to turn it into a multitouch sensor. The sensor board itself is mounted below an LCD display along with a shield with a slit in it to help filter out ambient light. Above the screen a series of LEDs shine down on the sensor. When you break the beams with your finger it casts a series of shadows which are picked up by the sensor and processed in software. Watch the clip after the break to see it for yourself. It has no problem detecting and tracking multiple contact points.

[Read more...]

LED artwork disappears right before your eyes

take_a_picture_demo

If you walked into an art gallery and saw nothing but blank canvases lining the wall, you might be compelled to demand your money back, or assume that you had discovered the world’s laziest artist. If this gallery happened to be displaying work by [Brad Blucher and Kyle Clements] however, you would be mistaken.

These two artists have collaborated to create a series of works titled, “Take a Picture“. Each picture they have built is constructed to look like an empty canvas when viewed with the naked eye. If you were to take a picture of the canvas with your cell phone or digital camera however, a whole new world would open up in front of your eyes. Their artwork is constructed using infrared LEDs, which cannot be seen with the naked eye, but are visible to nearly any CMOS or CCD sensor on the market. The images range from simple smiley faces and objects to abstract geometric shapes.

It’s a very simple, yet novel approach, and we happen to think it’s pretty cool. The artists have not said what they have planned for this project in the future, but we’d love to see it expanded using larger LED arrays to display higher-resolution images, or even short movies.

Keep reading to see how they went about creating these works of art as well as a promo video demonstrating the effect.

[Read more...]

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