Using Echoes of Light to Turn Walls into Mirrors

using a wall as a mirror


[Matthias] recently published a paper he worked on, in which he details how his group managed to reconstruct a hidden scene using a wall as a mirror in a reasonably priced manner. A modified time-of-flight camera (PMD CamBoard Nano) was used to precisely know when short bursts of light were coming back to its sensor. In the picture shown above the blue represents the camera’s field of view. The green box is the 1.5m*1.5m*2.0m scene of interest and we’re quite sure you already know that the source of illumination, a laser, is shown in red.

As you can guess, the main challenge in this experience was to figure out where the three-times reflected light hitting camera was coming from. As the laser needed to be synchronized with the camera’s exposure cycle it is very interesting to note that part of the challenge was to crack the latter open to sniff the correct signals. Illumination conditions have limited impact on their achieved tolerance of +-15cm.

Pwn Your GoPro: Scripting, WiFi, and Bus Hacking


GoPro cameras come out of the box with a huge set of features. Most people will be satisfied, or possibly even overwhelmed by the available options, but if you’re able to do some of these hacks, you’ll be able to expand your camera’s capabilities even more. They can, however, void your warranty, so as with most hacking, do these at your own risk.

[Read more...]

Cheap-Thermocam Gets an Impressive Rehaul


[Max Ritter] is a 21 year old student of information technology at the University of Applied Science at Weingarten, Germany. Three years ago he brought us the DIY Cheap-Thermocam, a tool for thermal imaging that cost <$100. Since then he’s made a few upgrades.

The original Cheap-Thermocam made use of an Arduino, the sensor from a thermometer gun and a few XY servos. In about 2 minutes the XY servos can scan and measure 1344 points using the thermometer’s sensor, creating a heat-vision map of 42 x 32 pixels — not amazing, but it worked — and it was cheap!

The new version (V3) has its own ARM Cortex M3 processor, it measures 3072 points in 2 minutes from -70°C to 380°C with an accuracy of 0.5°C, and it exports its images at a resolution of 640 x 480 –close to commercial offerings! It’s not capable of real-time scanning, but for the majority of purposes you need one of these for — it’s really not that necessary.

[Read more...]

Sense & Spray Air Freshener Says Cheese


What happens when you take a remote controlled tarantula, an automatic air freshener, some PVC tube and a mechanical trigger release for a camera? Well, it’s definitely a hack, that’s for sure — you get a remote camera shutter release!

[Michael] loves his Panasonic LX7, but unfortunately, it doesn’t have a trigger release! It does however except a hot shoe adapter to use with a manual release. All [Michael] had to do now was make it remote controlled.

If you’ve ever taken apart an automatic air freshener you know that they are a treasure trove of parts, ripe for the hacking. Specifically, they have a very nice linear actuator which can be used for all kinds of fun things. In this case, it works great for pressing the manual shutter release cable. The next step is controlling it. To do this, [Michael] found a cheap RC toy, a $10 stuffed tarantula oddly enough — By taking it apart he was able to make use of its controller to turn on the air freshener, effectively turning his contraption into a remote controlled shutter release.

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Smile Meter Reacts to Your Expressions With Pharrell’s Happy

MIT's Smile Meter

Here’s a clever use of a webcam and some facial recognition software — They call it Happy ++ and it will DJ [Pharrell's] Happy according to how much you’re smiling (or not at all!).

It’s another project to come out of MIT’s Media Lab for a spring event this year by [Rob, Dan & Javier]. The facial tracking software was re-used from an older project, the MIT Mood Meter, which was a clever installation that had several zones on campus tracking the apparent “happiness” of the students walking by.

To create the program they’ve split up the song Happy into its various components. Drums, vocals, band, and the full mix. As the webcam recognizes a smile, it records the intensity, which in turn turns up the vocals and band. If no smiling is present there is only a drum beat.  [Read more...]

Repairing a Nikon D3


There are few products out there as electronically and mechanically complex as a modern DSLR. Between the sensor, shutter, various LCD screens, and Flexible Printed Circuit boards (FPC) running everywhere, it’s enough to make even the most organized DIY repair person quake in fear. [TiN] over at the EEVblog forums wasn’t scared off though, as he bought a broken Nikon D3 on eBay in hopes of repairing it.

The D3 was Nikon’s top of the line professional camera in 2008. With a 12 Megapixel Full frame sensor and a host of other features, used models still command a good portion of the original $5000 USD price. [TiN's] camera was described as having been dropped, and was dead on arrival, exactly as it had been described on eBay. The battery door was destroyed, so [TiN] connected an external supply. The camera was still dead, so it was time to dig in. Thanks to the internet, [TiN] was able to find a service manual for the camera. He decided to check the power supply board next. A TO225 package transistor with an obvious hole blown in the front was a good starting point.

[TiN] replaced the transistor and the camera sprang to life. The main LCD showed the live sensor view, and it would take pictures. All was not perfect though, as the two auxiliary LCDs were still dead, and the D3’s mirror would get stuck every other shot, leading to an error display.

Click past the break for the rest of [TiN's] story.

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Catching Drops of Water With LEDs

Ever wonder how they capture seemingly perfectly timed photographs of water droplets? Most of the time it’s done by using an optointerrupter whereby it detects the droplet falling and then triggers a light source a few milliseconds later with your camera ready and waiting.

This is typically done with something called an air gap flash, which is usually rather expensive or difficult to make, but [Michal's] figured out another easier way suitable for some applications — using an array of LEDs to illuminate the scene.

He’s got a IR diode, a photo-resistor, a few spacers, some plastic and  a bunch of hot glue to make up his optointerrupter. When the droplet passes through the IR beam it breaks the signal from the photo-resistor which then triggers his ATmega48P. It waits 80 milliseconds (he timed it out) and then turns on the LEDs for approximately 50 microseconds. Meanwhile his camera is watching the whole event with a shutter-speed of a few seconds.

This works because LEDs have rise and fall times that are much shorter than a traditional camera flash — normal flashes light up for 1-2 milliseconds, as opposed to this 50 microsecond LED flash. Just take a look at some of the pictures!

[Read more...]


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