Speech Synthesizing Valentine From 1991

February 18, 2013 by 21 Comments

Internals

Back in 1991, a young [Backwoods Engineer] and his new wife went to a Valentines day get together. One of the conditions of the shindig was having the guys make – not buy – a Valentines day card. Go big or go home, he though, and after a few days he had a talking Valentines day card that would become one of his wife’s most treasured possessions.

The early 90s were a different time; in case you haven’t yet been made to feel very old yet today, 1991 is closer to 1970 than 2013 is to 1991. Likewise, the circuitry inside this heartfelt talking token of appreciation bears more resemblance to something from a 1970s electronics magazine than an Arduino project of today.

The project is powered by an old Intel MCS-48 microcontroller attached to one of the old speech synthesis chips Radio Shack used to sell. These are, in turn, connected to a programmable logic chip and a masked ROM that translates English words into phonemes for the speech synthesizer.

The entire device is constructed on a hacked up piece of perf board and a few wire wrap sockets; sturdy construction, even if the battery compartment has been replaced a few times.

As for what the talking valentine says? “”OK!  Hello, I am a Talking Valentine Card.  “Love Is A Many-Splendored Thing” and in this case also needs batteries!” You can check that out after the break.

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Building A Six-channel Floppy Drive Synth From Start To Finish

February 13, 2013 by 27 Comments

floppy

We’ve seen scores of floppy drives play music, but never before have we seen a project as clean as [Rupert]’s Moppyduino. It’s an Arduino-based board that controls the stepper motors in six separate floppy drives, coaxing them in to playing music from a MIDI file.

The Moppyduino is more than just a convenient way to control the stepper motors in six floppy drives. It’s also a great example of what can be done with home PCB fabrication; the entire project was designed and constructed in [Rupert]’s workshop.

After designing the circuit, [Rupert] printed it out on a laser printer onto a plastic transparency sheet. This was transferred over to a copper clad board, etched, and drilled. After assembly, [Rupert] attached a USB FTDI controller to receive data converted from MIDI data with a Java app.

The end result – housed in a custom Corian enclosure – is one of the best looking floppy drive synths we’ve ever seen. You can check out the process of building this awesome instrument after the break.

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Build A $360 Synthetic Aperture Radar With MIT’s OpenCourseware

December 18, 2012 by 38 Comments

A few profs from MIT’s Lincoln Lab are giving those poor MIT undergrads something to do over winter break: they’re teaching a three-week course on building a laptop-powered radar system capable of radar ranging, doppler, and synthetic aperture imaging. Interestingly, the radar system that teams will build for the class has a BOM totaling $360, and they’re also putting the entire class online if you’d like to follow along and build your own.

From the lecture notes from the course, the radio system is made out of an off-the-shelf  LNA, oscillator, and  splitter. By connecting two coffee can ‘cantennas’, it’s possible to record a .WAV file from the signal coming from the radar and use MATLAB to turn that audio signal into a doppler radar.

It’s a very ambitious project that goes deep down the rabbit hole of RF and analog design. One of the lecturers made a YouTube demo of the radar in ranging mode; you can check that out after the break.

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Atari Punk Stick Puts A Synth In A Joystick

November 7, 2012 by 8 Comments

[youtube=http://www.youtube.com/watch?v=ngXrTd-8jf4&w=470]

The Atari Punk Console, a tiny synthesizer based on the ubiquitous 555 timer chip, is the first build de rigueur for any budding electronic wizard wanting to build musical devices. With just a handful of caps, resistors, and a pair of pots, the APC is a fabulously fun and easy build made even cooler by [Pat]’s addition of a joystick.

The circuit of the Atari Punk Console consists of a 556 chip – basically two 555s put into the same package – and a pair of potentiometers to control the frequency and output of this very basic synth. Since most joysticks are just two pots arranged on an X-Y mount, [Pat] thought it would be cool to control his APC without twiddling knobs, and instead sweeping a joystick around.

After acquiring an old Microsoft joystick from his local Goodwill, [Pat] wired up his Atari Punk Console to the joystick, using the ‘fire’ button to turn the output on and off. The result is everything between a low machine gun-like tone to a nasal square wave that will hopefully keep pace with your chip-based audiophile friends.

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ATmega1284 As An 8-voice 32 KHz Synthesizer

November 2, 2012 by 10 Comments

A couple of things strike us about this 8-voice 32 kHz synthesizer. First is the cleanliness of the prototype. As you can see, each part has plenty of room on its own board and all are interconnected by 10-pin IDC ribbon connectors. But you’ll have to see the video after the break to enjoy the impressive sound that this puts out. You’ll hear it play the Super Mario Bros. theme; it does it with passion!

To get audio from the digital microcontroller [Mike] built his own R2R digital to analog converter. The resistor ladder is built from sixteen resistors, which feed a rail-to-rail amplifier. The sound is mono but the playback is polyphonic thanks to the work done by the ATmega1284. It is reading MIDI commands coming in from an external controller (we assume it’s the computer on which the hardware is sitting). The chip’s 128 KB of Flash memory leave plenty of room to store samples, which are selected from a lookup table based on the MIDI data. If more than one sample is to be played the chip averages the data and sets the 8-bit output port accordingly.

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Creating A MIDI Synth From A Commodore SID

October 18, 2012 by 24 Comments

The Commodore SID was the audio chip in the venerable Commodore 64 and in the 30 years since release has attained classic status and become one of the best ways to get your chiptune on. Designed by famous synthesizer designer [Bob Yannes], it was only a matter of time before we saw a real, homebrew MIDI synth based on the Commodore SID.

Because real SID chips are rare as hen’s teeth nowadays, [Jeff Ledger] built his SID synth around an emulated system running on a Pocket Mini Computer. This very cool microcontroller platform runs on the Parallax Propeller. An emulated SID runs in one of the Propeller’s 8 cores, with the remaining cores kept open for reading MIDI notes and displaying info on a display.

The hardware portion of this build is amazingly simple; just an optoisolater, a few resistors, and a diode connect a MIDI keyboard to the Pocket Mini Computer. The buttons and dials on [Jeff]’s MIDI keyboard control the waveforms, filters, and envelope controls. A very neat setup if we do say so ourselves, and just perfect if you’re needing more chiptunes in your life.

You can check out [Jeff]’s video after the break.

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Nebulophone Microcontroller Synthesizer Project Sounds Great

October 17, 2012 by 11 Comments

Judging from the video (found after the break) the Nebulophone is one of the best sounding DIY synthesizers we’ve seen. Especially when you consider the simplicity of the hardware design. It uses an AVR chip and an OpAmp. The rest of the parts are just a few handfuls of inexpensive components.

The device was developed by Bleep Labs, and they sell the synthesizer kit seen on the left. But since it’s an open source project you can follow their design to fabricate your own, which is what [BlinkyBlinky] did with his offering seen to the right.

An ATmega328 drives the device, which is the chip often used in the Arduino Duemilanove. The keyboard is a set of traces hooked to the microcontroller. These are tinned pads on the kit PCB, but the DIY version simply uses some adhesive copper foil with a jumper wire soldered to it. The keys are played with a probe that makes the electrical connection, a common practice on these stylophone type designs. Chances are you have everything on hand to make this happen so keep it in mind for that next cold winter weekend that’s making everyone a bit stir crazy.

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