These water droplets are not falling; they’re actually stuck in place. What we’re seeing is the effects of an acoustic levitator. The device was initially developed by NASA to simulate microgravity. Now it’s being used by the pharmaceutical industry do develop better drugs.
The two parts of the apparatus seen in the image above are both speakers. They put out a sound at about 22 kHz, which is beyond the human range of hearing. When precisely aligned they interfere with each other and create a standing wave. The droplets are trapped in the nodes of that wave.
So are these guys just playing around with the fancy lab equipment? Nope. The levitation is being used to evaporate water from a drug without the substance touching the sides of a container. This prevents the formation of crystals in the solution. But we like it for the novelty and would love to see someone put one of these together in their home workshop.
Don’t miss the mystical demo in the clip after the break.
The folks over at Adafruit have been busy designing an LED matrix wristwatch for a while now. The circuit works great, but since this watch is powered by a coin cell battery, they’d really like to get the power consumption as low as possible. This means they needed a test rig to measure the consumption of each firmware revision, but how exactly do you build a voltage logger that works with voltages and currents this small? It turned out to be a very interesting project, with plenty of info on how to build an accurate voltage logger for really small projects.
As you can see, a series of white LEDs inside of the transparent case which provide the simulated sunrise. As the days get short and the nights longer we do see the benefit of having your clock brighten the room before it jolts you out of your slumber. Speaking of, that alarm sound seems to be the weak link in his design. He’s using a square wave smoothed with capacitors to drive a speaker at either end of the case. We didn’t hear an example but we imagine this not the most gentle of sounds.
The rest of the design is quite well done. He’s using a 4×20 Character LCD display and adjusts the backlight using PWM. A DCF77 radio feeds data from an atomic clock signal to the MSP430 chip which runs the clock. There’s even a battery backup in case the power goes out.
The PlayStation Development Network is hosting a six-month long competition to develop homebrew games for the original PlayStation.We don’t get many homebrew games for old systems in our tip line, so if you’d like to show something off, send it in.
This is how you promote a kickstarter
[Andy] has been working on an SNES Ethernet adapter and he’s finally got it working. Basically, it’s an ATMega644 with a Wiznet adapter connected to the second controller port. The ATMega sends… something, probably not packets… to the SNES where it is decoded with the help of some 65816 assembly on a PowerPak development cartridge. Why is he doing this? To keep track of a kickstarter project, of course.
What exactly is [Jeri] building?
[Jeri] put up an awesome tutorial going over the ins and outs of static and dynamic flip-flops. There’s a touch of historical commentary explaining why dynamic registers were used so much in the 70s and 80s before the industry switched over to static designs (transistors were big back then, and dynamic systems needed less chip area). At the end of her video, [Jeri] shows off a bucket-brigade sequencer of sort that goes through 15 unique patterns. We’re just left wondering what it’s for.
Nintendo gave [MikenGary] a Wii U and asked them to make a film inspired by 30 years of Nintendo lore and characters. They did an awesome job thanks in no small part to Hackaday boss man [Caleb](supplied the fire), writer [Ryan] (costume construction) and a bunch of people over at the Squidfoo hackerspace.
We’re partial to using gedit and a makefile for our AVR projects. But for the most part we don’t a debugger with those smaller chips. Now that we’re getting going with ARM processors we use debugging all the time and Eclipse is a great way to combine code writing, compiling, and debugging in one place. Sure, we could use one of TI’s provided IDEs (some of them are based on Eclipse), but we’d rather build our tools up ourselves. [Doragasu] is making this a snap with his Eclipse for Stellaris Launchpad tutorial.
He illustrates every step with a screenshot like the one seen above. Here he is including the driverlib from StellarisWare in the linking step. After all of the compiler and linker settings are just right all you need to do is make a copy of the template to start a new project. The final part of the setup configures lm4flash to write binaries to the chip, and configures OpenOCD for use when debugging.
The video game industry must be one of the most secretive sectors when it comes to developing the electronic hardware used in the gaming consoles. The big guys don’t want to give anything away — to the competition or to the hackers who will try to get around their security measures. But it seems Sifteo doesn’t share those secretive values. We had a great time reading about the bumpy ride for the developers bringing the gaming system from concept to market. [Micah Elizabeth Scott] wrote the guest post for Adafruit Industries. She was brought on as an engineer for the Sifteo project just after the first version of the interactive gaming cube was released. From her narrative it seems like this was the top of the big hill on the roller coaster ride for the company.
What’s seen above is one gaming cube. The system developed in [Beth’s] story puts together multiple cubes for each game. The issue at hand when she joined the company was how to put more power in the hardware and rely less heavily on a computer to which it was tethered. She discusses cost of components versus features offered, how to deliver the games to the system, and all that the team learned from studying successful consoles that came before them like the long line of Nintendo hardware. It’s a fascinating read if you’re interesting in how the sausage is made.
Wow, we’re seeing all kinds of good stuff from NYC Resistor today. [Caleb] found this link to [Hudson’s] early work on a geeky wristwatch. It is based around an HDSP-2112 eight-digit alpha-numeric display. Each digit is a 5×7 array of LEDs, but the look of it really reminds us of [Woz’s] Nixie Wristwatch. The nice thing about using a display like this one is it’s much easier to drive and the power requirements don’t really call for special consideration either.
The display happens to be nearly the same footprint as the Teensy 2.0. In fact, the display is a bit longer. That makes it a perfect backpack, bringing everything necessary to drive the display. Check out the video after the break to see it scrolling the time as words, and displaying numbers.
This needs to have an RTC and portable power source before you can wear it around. But the proof is there. Perhaps [Hudson] will spin his own board with a uC that includes RTC capability and a charging circuit for a tiny Lithium cell.
