Simple Hack Completely Changes The Sound Of This Piano

We’re partial to musical instrument hacks around here, mainly because we find instruments to be fascinating machines. Few are more complex than the piano, and, as it turns out, few are quite so hackable. Still, we have to admit that this ragtime piano hack took us by surprise.

We always thought that the rich variety of tones that can be coaxed from a piano, from the tinny sound of an Old West saloon piano to the rich tones of a concert grand, were due mainly to the construction of the instrument and the way it’s played. Not so, apparently, as [Measured Workshop] demonstrated by installing a “mandolin rail” in a small upright piano. The instrument had seen better days, so step one was disassembly and cleaning. A wooden rail spanning the entire width of the string board was added, with a curtain of fabric draping down to the level of the hammers. The curtain was cut into a fringe in the same spacing as the hammers – marking the hammer locations with cornstarch was a nice trick – and metal clips were crimped to each fringe. The completed mandolin rail can be raised and lowered using a new foot pedal, completely changing the tone as the hammers hit the strings with the metal clips rather than their soft felt heads. It makes the piano sound a little like a harpsichord, or the aforementioned saloon instrument, and at the touch of a foot, it’s back to its original tone.

Most of the piano hacks we offer tend toward the electronic variety, so it’s nice to see a purely mechanical piano hack for a change. And if the hacked piano doesn’t work out as an instrument, you can always turn it into a workbench.

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ADSL Robustness Verified By Running Over Wet String

A core part of the hacker mentality is the desire to test limits: trying out ideas to see if something interesting, informative, and/or entertaining comes out of it. Some employees of Andrews & Arnold (a UK network provider) applied this mentality towards connecting their ADSL test equipment to some unlikely materials. The verdict of experiment: yes, ADSL works over wet string.

ADSL itself is something of an ingenious hack, carrying data over decades-old telephone wires designed only for voice. ADSL accomplished this in part through robust error correction measures keeping the bytes flowing through lines that were not originally designed for ADSL frequencies. The flow of bytes may slow over bad lines, but they will keep moving.

How bad? In this case, a pair of strings dampened with salty water. But there are limits: the same type of string dampened with just plain water was not enough to carry ADSL.

The pictures of the test setup also spoke volumes. They ran the wet string across a space that looked much like every hacker workspace, salt water dripping on the industrial carpet. Experimenting and learning right where you are, using what you have on hand, are hallmarks of hacker resourcefulness. Fancy laboratory not required.

Thanks to [chris] and [Spencer] for the tips.

Save ESP8266 RAM with PROGMEM

When [sticilface] started using the Arduino IDE to program an ESP8266, he found he was running out of RAM quickly. The culprit? Strings. That’s not surprising. Strings can be long and many strings like prompts and the like don’t ever change. There is a way to tell the compiler you’d like to store data that won’t change in program storage instead of RAM. They still eat up memory, of course, but you have a lot more program storage than you do RAM on a typical device. He posted his results on a Gist.

On the face of it, it is simple enough to define a memory allocation with the PROGMEM keyword. There’s also macros that make things easier and a host of functions for dealing with strings in program space (basically, the standard C library calls with a _P suffix).

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D-Link Fails at Strings

Small Office and Home Office (SOHO) wireless routers have terrible security. That’s nothing new. But it is somewhat sad that manufacturers just keep repurposing the same broken firmware. Case in point: D-Link’s new DIR-890L, which looks like a turtled hexapod. [Craig] looked behind the odd case and grabbed the latest firmware for this device from D-Link’s website. Then he found a serious vulnerability.

D-Link's DIR-890 Router

The usual process was applied to the firmware image. Extract it, run binwalk to find the various contents of the firmware image, and then extract the root filesystem. This contains all the code that runs the router’s various services.

The CGI scripts are an obvious place to poke for issues. [Colin] disassembled the single executable that handles all CGI requests and started looking at the code that handles Home Network Administration Protocol (HNAP) requests. The first find was that system commands were being built using HNAP data. The data wasn’t being sanitized, so all that was needed was a way to bypass authentication.

This is where D-Link made a major error. They wanted to allow one specific URL to not require authentication. Seems simple, compare string A to string B and ensure they match. But they used the strstr function. This will return true if string A contains string B. Oops.

So authentication can be bypassed, telnetd can be started, and voila: a root shell on D-Link’s most pyramid-shaped router. Oh, and you can’t disable HNAP. May we suggest OpenWrt or dd-wrt?

Irregular Incurve robotic instrument

irregular_incurve

The Irregular Incurve is a robotic instrument built by [Xiaoyang Feng] as part of his ITP thesis work. It’s a MIDI instrument with an array of 12 strung bows mounted to a curved shower rod. The end of each bow has a tuning key. The strings are each picked using independently mounted arms. One servo controls the downward motion of the pick while the other controls the rotation of the shaft. A damper is also attached to each arm. The string vibrations are transferred to a spruce soundbox under the bridge. Below you can see a video of Gizmodo playing with it at the ITP show. Check out [Xiaoyang]’s Flickr set for images of the build process plus some early videos of the mechanism.

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