TMD-1 Makes Turing Machine Concepts Easy To Understand

For something that has been around since the 1930s and is so foundational to computer science, you’d think that the Turing machine, an abstraction for mechanical computation, would be easily understood. Making the abstract concepts easy to understand is what this Turing machine demonstrator aims to do.

The TMD-1 is a project that’s something of a departure from [Michael Gardi]’s usual fare, which has mostly been carefully crafted recreations of artifacts from the early days of computer history, like the Minivac 601  trainer and the DEC H-500 computer lab. The TMD-1 is, rather, a device that makes the principles of a Turing machine more concrete. To represent the concept of the “tape”, [Mike] used eight servo-controlled flip tiles. The “head” of the machine conceptually moves along the tape, its current position indicated by a lighted arrow while reading the status of the cell above it by polling the position of the servo.

Below the tape and head panel is the finite state machine through which the TMD-1 is programmed. [Mike] limited the machine to three states and four transitions three symbols, each of which is programmed by placing 3D-printed tiles on a matrix. Magnets were inserted into cavities during printing; Hall Effect sensors in the PCB below the matrix read the pattern of magnets to determine which tiles are where. The video below shows the TMD-1 counting from 0 to 10, which is enough to demonstrate the basics of Turing machines.

It’s hard not to comment on the irony of a Turing machine being run by an Arduino, but given that [Mike]’s goal was to make abstract concepts easy to understand, it makes perfect sense to leverage the platform rather than try to do this with discrete logic. And you can’t argue with results — TMD-1 made Turing machines clear to us for the first time.

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REM Detection Lets You Boss Around Your Dreams

[Michael] has been working on projects involving lucid dreaming for a long time. The recurring problem with most projects of this nature, though, is that they often rely on some sort of headgear or other wearable which can be cumbersome to actually sleep with. He seems to have made some headway on that problem by replacing some of the offending equipment with a small camera that can detect eye movements just as well as other methods.

The idea behind projects like this is that a piece of hardware detects when the user is in REM sleep, and activates some cue which alerts the sleeper to the fact that they’re dreaming (without waking them up). Then, the sleeper can take control of the dream. The new device uses a small camera that dangles in front of an eye, which is close enough to monitor the eye’s movement. It measures the amount of change between each frame, logs the movements throughout the night and plays audio tracks or triggers other hardware when eye movements are detected.

[Michael]’s goal is to eventually communicate from inside of a dream, and has gone a long way to achieving that goal. Now that this device is more comfortable and more reliable, the dream is closer to reality. [Michael] is looking for volunteers to provide sleep logs and run tests, so if you’re interested then check out the project!

Stylin’ HMD

Watch out, these sunglasses are actually a head mounted display. [Staffan] says he’s wanted dataglasses since ’95, but whats currently out there makes the user look ridiculous, and we have to agree. While his forum posts are a little lacking in detail, he’s promised us more info soon. And for now lets us know at least the resolution, well sort of: Its either 480×1280 or 480x427x3, you can be the judge. Update: [Staffan] has clarified “The resolution is 480*1280 true pixels. It is accomplished by spanning the screen across two Kopin CyberDisplay VGA modules.”

Regardless, [Staffan] is looking for help perfecting the glasses, with what in particular we’re not sure, but the project looks promising and we hope he keeps up the good work.

Rotary Display Uses VCR Head And LEDs

[Daniel Daigle] is developing a rotary display that uses persistence of vision to graph data. The hardware he used includes a spinning head from a VCR, some LEDs, and a timing circuit to display 360 degrees of data. His timing input uses a waveform so this will work with any application where you can generate a PWM signal.

Check out his videos after the break that demonstrate a graph with a single line and another with six display lines.

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Track The Sun For Home Lighting.

sun_track

Have a room in your house that really could benefit from some sunlight? Build a Suntrack to reflect light in as long as possible. The two axis motor set up is built from a couple of  satellite dish positioning motors with the control electronics removed. The whole thing is controlled with a PIC 18f2520.  Once calibrated, it will reflect the sun into your room, updating every twenty seconds. While this may not be the most efficient way of lighting a room, it is a cool way to do it if you absolutely must have sunlight. We can’t help but wonder if there would be a way of using a solar powered system to do this to save energy. Could this possibly be done using BEAMhead” circuit?

[via Hacked Gadgets]