Brewing up some quantum dots

We’re taking a field trip from the backyard, garage, and basement hacking in order to look in on what research scientists are up to these days. A group from the Johns Hopkins Institute for NanoBioTechnology has been manufacturing quantum dots for use in the medical field. Made up of Cadmium Selenide, this is a nanomaterial that you can think of as individual crystals of the smallest size possible. Quantum dots have many uses. Here, [Charli Dvoracek] takes the recently manufactured dots and activates them with antibodies capable of targeting cancer cells. Once mixed with a biological sample, the dots embed themselves in the walls of the cancer, allowing the researchers to find those cells thanks to the phosphorescent properties of the dots.

The video after the breaks walks us through the various steps involved in growing these dots. [Charli] has the benefit of a fully outfitted lab, using tools like an argon-filled glove box to protect her from harmful off-gases. You’re not likely have this sort of thing in your home laboratory, but as we’ve seen before, you can make some of your own equipment, and produce interesting chemicals with simple processes. If you’re someone who already tinkers with chemistry experiments we want to hear about your exploits so please drop us a tip about what you’re up to.

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USB killswitch turns off your home entertainment bling automatically

Finally, the USB port on the back of your television can be tapped for something useful. [Don] is using this add-on device to automatically cut the power to his Ambilight clone. Initially, he got tired of unplugging the power adapter each time he shut off the television, so he added a switch. But laziness overcame him and he decided he needed an automatic method. After probing around on the connections available, he established that the serial interface (normally used for servicing the device) was not of any use, but the USB port is. He measured the voltage of the power bus to be 5V when the TV is on, and 0.15V when it is off. He whipped up the circuit you see above which uses the USB connection to trigger a relay, connecting power to his Ambilight clone when the television comes on, and disconnecting it when the set is switched off.

Our dream has always been an XBMC capable device that can Velcro to the back of a TV, and be powered from that USB port. Unfortunately the Beagle Board hasn’t yet made it to a stable level when running XBMC. Our next hope is the AppleTV 2, which can run XBMC but would require some hacking to get it working off of the USB port, raising concerns about how much current it would draw at 5V.

Halloween Hacks: Building a dark ride in a garage

Instead of the usual Jack-o-lanterns and creepy Halloween decorations, [Rick Murphy] built a dark ride in his garage a few years ago.

In case you’ve never been fortunate enough to see one in person, a dark ride is a track-based haunted house meant to be experienced on a small cart. Usually featuring sound, light, and animatronic displays, dark rides can be just as entertaining now as when you were eight years old.

[Rick]‘s dark ride, “Scream in the Dark” was built in his 2-car garage over a few years. The kids that went though the ride were genuinely scared, but that made the kids in line even more curious – just the reaction [Rick] wanted.

The build is for the most part completely modular. The track is made up of 4-foot square panels that have either a straight track or 90 degree bend. The modular design means [Rick]‘s garage doesn’t need to be a dark ride the entire year. The cart rides on this curved, raised track with the help of a few gear motors and 12 V battery pulled from a Power Wheels.

There’s a great gallery of the interior of the dark ride and a video after the break. If you’d like to build your own dark ride, check out for a whole bunch of dark ride and fun house enthusiasts.

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Wireless hackerspace music control

The crew at the Netherlands-based Bitlair hackerspace love their music, and have set up a digital jukebox for their workshop using mpd and fookebox. One problem that you run into with a bunch of different people working in one place is that everyone has their own distinct taste in music. The rhythmic “wub wub wub” of Dubstep might be great for some while leaving others trying to solder while simultaneously covering their ears. To ensure that everyone can exercise a musical veto (a la Empire Records) now and again, they built a Skipbutton which allows members to change what’s playing.

The button allows users to skip to the next song in the queue. as well as to control the volume of the space’s sound system. It uses an Arduino pro mini to run the show, sending signals to the mpd daemon using a 433 MHz transmitter. Bitlair is pretty large and they often spend time outdoors, so they had to ensure that the Skipbutton worked wherever they did. To do this, they built a Yagi-Uda antenna at the receiving end to ensure that the button functions no matter where it’s being triggered from.

Check out their wiki if you’re interested in making a similar system for your home or hackerspace – all of the code and schematics are available for the taking.

Vintage camera retrofit perfect for trolling strangers


[John] likes making things out of unusual junk, and decided to build something for the sole purpose of trolling others. He thought it would be funny to stuff a new digital camera into the body of an old, obsolete camera, just to see how people would react to it.

He considered several different cameras, including a bulky old Polaroid, eventually settling on a far more manageable Argus C3. The camera wasn’t quite big enough to fit his new digicam inside, so he built a mock body using black micarta. He attached the Argus’ front and back to his plastic box, then spent some time fitting his digital camera inside. He transferred knobs from the original camera to his new false body, adding to the authenticity, before taking it out for some test shots.

You can see the final result above, and we think you would be hard pressed to notice that there’s something amiss with his camera unless you spent some time taking a closer look at it. He says that it works well for the most part, and it’s definitely a conversation starter. People are always puzzled by the fact that he is using such and old camera, and doubly so when he tells them it can take about 4,000 shots before he has to “develop” his pictures.

Building a better clock to drive you insane

[Simon] came up with an improved version of Lord Vetinari’s clock that begs to be installed in waiting rooms around the world.

Last week, we were introduced to a real-life Vetinari Clock that keeps regular time but ticks at irregular intervals. It’s a great way to turn someone’s mind into porridge, but the original build broke after a few weeks because of some limitations in the clock drive. [Simon] built a very minimal circuit does away with these problems.

Just as in the first build, a microcontroller pulses the second hand motor once every second. As for the random component of this build, the microcontroller has a puts 32 bytes into a 128 byte array. The array is checked 4 times a second, and if the byte is 1, the second hand is incremented. If the byte is 0, time stops for a little bit. [Simon] included the schematic, board layout and code if you’d like to build one yourself.

There are a few drawbacks to this design; the pattern of ticking and not ticking is hard-coded into the microcontroller. Even though the 32 second long pattern shouldn’t be noticeable by watching the clock, it’s not an entirely random solution. Judging from the comments on the original build, using radioactive decay to increment a second might be a bit uncalled for.

We would like to see a second hand that stops when you look at it though. Facial recognition, anyone?

Remote-controlled VMUSIC2 audio player


[Ron] was looking for a way to play his MP3s around the house without having to use his computer. He also wanted the ability to remotely control his tunes with an old camcorder remote he had sitting around – not exactly a feature you would find in an off the shelf personal audio player.

Ultimately, he decided to construct his own remote-controlled audio player using a VMUSIC2 audio module, which can decode MP3s from any standard USB drive. The VMUSIC2 is controlled by a Propeller demo board, which also handles receiving and decoding IR signals from his camcorder remote. While he was originally dumping ID3 tag data to his computer for debugging purposes, he recently added an LCD screen for displaying song information in a more useful manner.

The MP3 player seems to work pretty well if the video below is any indication, though it’s begging for a nice enclosure to tie things together. We like the project so far, so we’re sure [Ron] won’t fail to impress when it’s completely finished.

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