The MIDI piano instructor is a tool aimed at those who wish to learn to play piano, but don’t want to take lessons. The LED bar mounted above the keys lights up to show you exactly what key to press and when. We’ve seen this available in some electronic keyboards for some time, but this unit would be able to fit any standard sized keyboard.  Check the page for schematics and pictures.

[via Flickr]

Everything about this Turing machine is absolutely brilliant. A Turing machine uses a strip of material to record, calculate, and change data. [Mike Davey] built this one using servo motors, a Parallax Propeller, felt-tipped pen, and 1000 feet of film leader. The machine writes characters to the leader, reads them using a grayscale camera, and erases them with a rotating felt cylinder.

Watch the video after the break, it covers every one of the intricate details that add up to [Mike's] perfect build. We loved his Nickel-O-Matic but he really outdid himself with this one. With our mouths still agape we’re going back for our fifth viewing.

[Thanks SheeEttin via Slashdot]

[Miguel A. Vallejo] wanted a portable spectrum analyzer for the 2.4GHz ISM band. No problem, there’s modules for that are easy to interface with a microcontroller and LCD screen. But carrying around a black project box doesn’t exactly scream ‘cool’ so he fit his spectrum analyzer inside of a cell phone. This made a lot of things easier for him; he already had a few old phones, he was able to use both the original battery and the original LCD screen, and a lot of the mounting work is already done for you. The only challenge was to fit his custom circuitry inside. By hacking off part of the CYWM6935 module and cutting some protoboard in the same shape as the original PCB he managed to get everything into this tiny portable package. Now he’s looking for a way to incorporate a charger, and an on/off switch.

If you don’t have an old cell phone sitting around you can try building a spectrum analyzer that uses a character display. But we’d suggest hitting up your friends for their old cellphones.  The screens are used in all kinds of fun projects.

True randomness can be hard to come by in the digital world. [Andy Green] is making it easier to get true entropy by using this random USB dongle. The Whirlygig uses a CPDL to gather data from a set of of oscillators. The oscillators have a constantly fluctuating frequency due to temperature changes; if they run faster they generate more heat which in turn slows them down. This, along with the variable latency associated with polling a USB device, gives great depth of randomness. The device is detected and mounted under ‘/dev/hw_random’ and can then be fed into ‘/dev/random’ using the rng-tools package. [Andy's] done a lot of testing, both on the hardware, and on the quality of randomness. We didn’t see an option to order this but he’s got hardware and firmware repositories so that you can throw one together yourself.

[Thanks Zunk]