Window Curtain Moves To Screen Pedestrians

October 15, 2010 by Mike Szczys 24 Comments

[Niklas Roy] built a motorized window curtain to screen out foot traffic in front of his window. When you hear “motorized curtain” you may think that this will move up and down but it doesn’t. Instead, the small curtain move horizontally to cover passersby as they travel down the sidewalk. This is accomplished using a camera in conjunction with some motion sensing software. In the video after the break you can see that the software also anticipates the movement, and ends up doing a good job of keeping the target covered. That’s thanks to the Processing sketch working in conjunction with a rotary encoder on the hardware setup. Details for both are available on the page linked above.

This harkens to other community involvement hacks we’ve seen like the subway stair piano, or the bottle recycling video game. It’s fun and quirky, which is not too much of a surprise as we saw a glimpse of that when we looked at [Niklas’] public fountain hydropower generator.

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Android Oscilloscope

October 14, 2010 by Mike Szczys 31 Comments

Here’s a 2-channel Oscilloscope for your Android phone. It uses a base module driven by a dsPIC for signal processing. From there, an LMX9838 Bluetooth module broadcasts the data to the phone so that the waveform can be displayed. [Yus] ported some Python code he had been using over to a set of Java and XML files in order to get it working on Android. This was actually the first time he worked with the SDK… we’d say he’s a quick learner. See it in action after the break.

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Cadsoft Eagle Migrating To XML

October 14, 2010 by Mike Szczys 16 Comments

[PT] posted about an exciting development from Cadsoft, the migration to XML based parts, schematics, and board layouts. The adoption of this open standard goes hand-in-hand with the open hardware initiatives people like [PT] have been pushing for.

Cadsoft Eagle is our go-to schematic and PCB software. We even have a tutorial which guides you through preparing your files for PCB manufacture. But the files containing parts libraries, schematics, and board layouts have always been binaries. A transition to XML means a lot of things. They will be easier to edit, and much friendlier for tracking changes using version control systems like SVN, CVS, Mercurial SCM, Git, etc. But immediately on our minds is the accessibility for hacking. Think of how easy XML parsing is in programs like Python. It should be snap to write scripts on a whim that will manipulate the XML files in any way imaginable. This doesn’t discount the value of Eagle, it extends the usability far beyond what any team of engineers at Cadsoft could produce by themselves. And for that, we say Bravo.

Touring The Available Nokia LCD Screens

October 14, 2010 by Mike Szczys 23 Comments

[Rossum’s] taking a look at the Nokia LCD screens that are both plentiful and begging to be bent to your will. For quite some time the Nokia 6100 screens have been used in a lot hacks, but he wanted to see what else is out there. He digs into his junk box of cell phones and comes up with a couple to test; the Nokia 6101 and Nokia 2760. The screens use a 3-wire SPI interface, which he sniffs out with a logic analyzer. At power-up the cellphone polls the screen to determine which type of LCD controller is connected. [Rossum] grabs these commands from the logic analyzer and uses it to determine the hardware in use with each screen.

He made himself a nice breakout board which has connectors for several different screens. The firmware he’s using detects when a screen is attached and switches to the applicable protocol for that display. Take a look at the video after the break.

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Assassin’s Creed Blades Make Us Wince

October 14, 2010 by Mike Szczys 109 Comments

[TheBserk] made himself a set of auto-locking and auto-retracting hidden blades inspired by those in the game Assassin’s Creed. As you can see in the demo (and build guides) after the break, they work really well. We don’t like the idea of sharpened metal ramming its way past our wrists. But it’s not the first time we’ve seen dangerous arm-mounted hacks.

Reminiscent of Taxi Driver, [TheBserk] uses drawer slides from the local home store for his build. They are cut to length, and modified using springs for the automatic action. There is a lock to keep the blade extended, and a pull-wire to actuate it. Although dangerous, the build is well done. We think someone has mechanical engineering in his future, and possibly a trip to the emergency room.

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Open Call: Send Us Your Debounce Code

October 13, 2010 by Mike Szczys 75 Comments

If you’ve ever designed an embedded system with at least one button you’ve had to deal with button debouncing. This is also know as contact bounce, a phenomenon where a button press can be registered as multiple button presses if not handled correctly. One way to take care of this is with a hardware filter built from a resistor-capacitor setup, or by using a couple of NAND gates. We find that [Jack Ganssle] put together the most comprehensive and approachable look at contact bounce which you should read through if you want to learn more.

We’re interested in software solutions for debouncing buttons. This seems to be one of the most common forum questions but it can be hard to find answers in the form of reliable code examples. Do you have debounce code that you depend on in every application? Are you willing to share it with the world? We’d like to gather as many examples as possible and publish them in one-post-to-rule-them-all.

Send your debounce code to: debounce@hackaday.com

Here’s some guidelines to follow:

Please only include debounce code. Get rid of other unrelated functions/etc.
You should send C code. If you want to also send an assembly code version that’s fine, but it must be supplementary to the C code.
Please comment your code. This will help others understand and use it. You may be tempted to explain the code in your email but this info is best placed in the code comments
Cite your sources. If you adapted this code from someone else’s please include a note about that in the code comments.

As an example we’ve included one of our favorite sets of debounce code after the break. Please note how it follows the guidelines listed above.

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LEGO Automatic Transmissions

October 13, 2010 by Mike Szczys 12 Comments

[AviatorBJP] is building some impressive automatic transmissions using LEGO parts. Your best bet is to check out his YouTube channel as he’s got a slew of videos related to topic. We’ve embedded test footage of first and second generation vehicles as well as the most recent flywheel design after the break. But we’re getting ahead of ourselves, let’s look at how the system works.

Each transmission centers on a mechanism that includes hinged arms attached to a central axle. The arms are held together with a rubber band but as the axle spins faster, they overcome the elastic force of the band and begin to pivot outward. This pulls the shaft in one direction, moving its gear up to the next position in the transmission box. To test the system [AviatorBJP] uses a treadmill. A string is attached to the front of the vehicle to keep it in place and the treadmill is switched on to simulate engine power.

This design is quite brilliant, and he’s not keeping it to himself. If you’ve grown tired of the manual LEGO transmission you built, you can follow his multi-video build process to make one of these for yourself.

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