USB Man-in-the-middle Adapter

The module works as a pass through, providing access to data and power lines for a USB device. [BadWolf] built it in order to sniff out communications between peripherals and the Universal Serial Bus. For now it just provides access to the different signals, but we think there’s quite a bit of usefulness in that. First off, the power rail is mapped out to a jumper, making it dead simple to monitor the voltage stability or patch in a multimeter to get feedback on current consumption. But you can also see in the foreground that a pin socket makes it easy to tap into the board using jumper wires. We think it would be a great breadboard adapter for USB work that would continue being useful after you’ve populated your first PCB for the prototype.

[BadWolf] has other plans in store for it though. He wants to intercept and decipher the communications happening on the data lines. In the video after the break he mentions the possibility of using a Bus Pirate for this (we have our doubts about that) but plans to start his testing with an STM32 discovery kit. We can’t wait to see what he comes up with.

Tokyo Hackerspace Helping Disaster Victims

We, like the rest of the world, have watched in horror as footage of the recent earthquake-caused disaster has been reported from northern Japan. It’s easy to watch video and see nothing but distruction, however, life goes on and [Akiba] is looking for a way to help the recovery efforts. He mentions that one of the big needs in the disaster area right now is for light, as the power infrastructure has been heavily damaged. The mason jar seen above is a Kimono Lantern that was meant to accent a garden at night. It has a solar cell – one NiMH rechargeable battery – and one bright LED along with a charging circuit. It was designed in the Tokyo Hackerspace and they released the build files in hopes that a large number can be donated to those in need. With a reasonable amount of daylight, the single cell battery can be charged enough to provide 10 hours of light from the little device.

How can our hacks help others? That question has been on our minds for the last few days. Light is a great first step. But we’ve also wondered about information networks to help coordinate rescue and cleanup workers. There are hacks that bring WiFi using wind power or solar power. What other hacks do you think would be useful to aid in the recovery process?

DsPIC-based Spectrum Analyzer


[Debraj] wrote to us describing a project he recently completed – a  simple, compact spectrum analyzer using a 16-bit dsPIC microcontroller.

The analyzer is fed an analog signal, which is passed through a large resistor followed by an opamp. A DC offset is then applied to the signal, after which it is passed through a software-programmable gain amplifier before being fed into the dsPIC’s analog input. A Fast Fourier Transform calculation is done using code provided by the PIC’s manufacturer once 128 samples have been collected. The results are then displayed on the attached LCD in real-time.

If you get a chance, take a look at the video embedded below for a walkthrough and demonstration of his analyzer. [Debraj] says that the analyzer was built to measure harmonics in his home power lines, but for demonstration purposes, he has used a simple function generator instead.

If you’re interested in seeing some other spectrum analyzers, be sure to check out these items we featured in the past.

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Toothpaste Diode

While reading the back of a tube a toothpaste [Underling] noticed that one of the ingredients was hydrated silica, gears turned, sparks flew and he wondered if he could possibly make a transistor out of the stuff. After thinking about it he decided that making a diode out of toothpaste would be easier and still prove the idea.

The quick n dirty explanation of this is he smeared some toothpaste on a bit of chrome and set it on fire with a propane torch. When set on fire the result is silica and sodium, heat causes the sodium to bond with the silica and since sodium is negatively charged this forms an n-type semiconductor or half of the diode. Chrome is used for the second half of the diode, for a few reasons, he had some lying around, its positivity charged, and the toothpaste contains a little bit of lye which oxidizes the chrome and burns off, bonding the silica to the metal.

What is left is a thin layer of chrome doped silicon under a layer of sodium doped silicon, which in spots where everything is perfect, acts like a diode, blocking current in one direction but not the other.

Motorcycle Sound Effects

[Winfred] was thinking one day, of how the world would be a different place if everything we owned had little start up and shut down sounds like our computers. Historically computers would just beep after passing their power on self test, and many PC’s still do, but in the 1980’s as machines became more powerful and home users wanted more flexibility in their hardware, startup chimes started to creep into our lives. And why not extend that little moment of joy to other objects, like adding Windows XP startup and shutdown sounds to your motorcycle.

Electronically the bill of materials looks like hobby shop catalog, featuring a Freeduino (Arduino variant), Adafruit wave shield, marine speakers, and a cheap-o mp3 amplifier from ebay. While admittedly not the cheapest way to play an audio clip [Winfred] offers a few suggestions to help drop the 100$ price tag, including just skipping it all together and mimicking the sounds with your voice.

Its a fun idea, its sure to earn some odd looks from his neighbors, and it will probably make you chuckle a little too.

PWM-controlled LED Display Is Truly A Gift From The Heart


Instructables user [Simon] admits he addicted to electronics. Lucky for him, his wife of 15 years is pretty cool with, or at least tolerant of his need to fiddle with anything that plugs in. As a gift for their wedding anniversary, he decided it would be neat to combine his love for his wife with his love for electronics. The result is the the RGB LED “Love Heart” you see above. He built an RGB LED circuit controlled by a PIC12F683 microcontroller, which shines into a hand-etched plexi-glass panel.

The LED color is controlled using PWM, as you would expect. What you might not expect however, is the lengths [Simon] would travel to ensure nearly perfect color and brightness matching across the 5 LEDs he used in his project. Since RGB LEDs do not have a uniform output brightness, he used a Lux meter to precisely measure the white balance of each LED. He then plotted the results in Excel before coding the PWM driver. Now that’s devotion! Once the LEDs were settled, he went about constructing the rest of the LED panel.

If you are interested in building one for your sweetheart, [Simon] has you covered – he provides all of the schematics, templates, and source code required to get the job done.

Continue reading to see a video of his heart panel in action.

Continue reading “PWM-controlled LED Display Is Truly A Gift From The Heart”