Classical’s Greatest Hits On Hardware’s Greatest Flops

February 17, 2011 by Mike Szczys 19 Comments

We get a lot of tips about old hardware playing recognizable tunes. But once in a while one of these projects goes above and beyond the others and this is a shining example of great hardware music. [FunToTheHead] put together a music video (embedded after the break) that shows his custom MIDI device playing Bach’s Toccata in d minor. He left some comments that clue us into the way he did it. Most obviously, he’s using the stepper motors from four floppy drives to create precisely pitched sounds. Internally, a PIC 18F14K50 acts as a MIDI-over-USB device, taking commands for all 128 MIDI notes as well as the pitch bends associated with them. The first four channels are played directly on each drive and the other twelve are triaged among the hardware by the microprocessor. But for the results heard in the video you’ll need to code your MIDI files by hand.

Bonus points to the video editor for the Phantom’s floppy-laden appearance in the video… it’s good to laugh!

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Punch Tape Musical Synth

February 16, 2011 by Mike Nathan 26 Comments

synthanola

[Jeri Ellsworth] sent over a 555 design contest entry that struck her as particularly interesting. The Synthanola is a three-channel music synthesizer that accepts input from an old Heathkit paper tape reader. While this hack might seem overly retro, it’s actually an extremely appropriate use of technology, as the Heathkit H-10 and the 555 timer were both popular tech in the 70’s. This retro-focused synth uses fourteen 555 timers, twelve of which are dedicated to synthesizing audio. If this entry does not win the contest, it certainly must be a strong contender for most 555 timers used.

[Thrashbarg] gives a detailed explanation of the logic used to drive the music playback from the punch tape, as well as full circuit diagrams for his entry. So far he has encoded MP3s of Bach’s Invention and Fugue in D Minor to tape, with hopefully more to come. In order to truly appreciate his efforts, the Synthanola should be seen as well as heard. Stick around for a pair of videos of the synth in action.

If you’re interested in seeing more 555 contest entries, be sure to check out some of our previously featured projects.

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LED Dog Collar, Christmas Edition

February 11, 2011 by Caleb Kraft 11 Comments

[Aaron] says in our comments that he also made an LED dog collar. This Christmas themed dog collar uses an ATTiny13a and a hand full of red and green LEDs (28?). While the animations aren’t as complex as the collar we posted earlier today, we though you might enjoy this one as well. From the description, we think that the LEDs simply fade back and forth between red and green. We think that [Aaron] did a great job. He has included the source code and schematic on his site, but sadly there’s no video of this collar in action.

Logisim: Open Source Digital Logic Simulator

February 9, 2011 by Mike Szczys 28 Comments

[Spi Waterwing] wrote in to make sure that we were aware of Logisim, a Java-based open source digital logic simulator. We’ve used Atanua quite a bit in the past but hadn’t heard of this program. It seems to have a pretty big educational following and right off the bat it’s got a feature we’ve always wanted, the ability to build your own ‘black box’ logic devices. That is to say you can build your own circuit out of logic gates and then package it into a part to be plopped into your next design. What it doesn’t have is the series logic chips that we’re used to with Atanua, but you can build your own with the black box feature if you really need that kind of functionality.

So grab a copy and try building that binary calculator project from last month.

Animating An LED Matrix Without A Microcontroller

February 9, 2011 by Mike Szczys 20 Comments

[Konstantin] had some extra 27C256 EPROMS lying around and decided to use them to animate an 8×8 LED matrix. He’s not only using them to store data, but driving the display with them as well. The chip holds 32 kilobytes of data which equates to 4096 frames of animation. A 32 kHz clock circuit works with some ripple counters to scroll through each byte of stored data, turning on the columns while sinking the proper row. Of course current protection is a must so there is a ULN2308A darlington driver and some 2N2907 transistors at work, but you won’t find a programmable microcontroller. Neat!

Yep, you read that right. The picture above shows an EPROM chip that requires a UV light source to erase the data.

[Thanks Kopfkopfkopfaffe]

DIY Clapper

February 7, 2011 by Kevin Dady 11 Comments

[Patrick’s] latest Instructable walks us though making a clap clap on / clap clap off type of switching circuit, similar in use to that sometimes popular commercial product seen on TV. He does this by using a standard electret microphone, half of an LM324 op amp, a voltage comparator and a PIC micro controller.

The operation of the device is as simple as its wiring, the microphone picks up sound and produces a signal, that signal is stripped of its DC component and fed into the op amp, after 2 stages of amplification the signal passes though a voltage comparator, and if the sound was loud enough a timer is triggered on the pic. Two claps within the specified amount of time, the micro then switches on a relay which can toggle your outside appliance (keeping the load in mind).

On the last page [Patrick] also gives a rough outline of how to make a single clap on / off variant using a 555 timer and some flip flops. Join us for a quick video after the break, and be sure to check this one out.

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Analog Computer Does Math

February 4, 2011 by Mike Szczys 14 Comments

This analog computer can multiply, divide, square numbers, and find square roots. It has a maximum result of ten billion with an average precision of 2-3%. [Miroslav’s] build recreates something he saw in a Popular Electronics magazine. It uses a resistor network made up of three potentiometers with a digital multimeter is an integral part of the machine. To multiply a number you set the needles on the first two knobs to the numbers on which you are operating. To find the result turn the third knob until the multimeter has been zeroed out and read the value that knob is pointing to. It seems much more simple than some of the discrete logic computers we’ve seen, yet it’s just as interesting.