Circuit Bent Toy Keyboard is MIDI Controlled

tymkrsKeyboard
The [Tymkrs] crew has come up with a pretty neat circuit bent toy keyboard hack. It’s been a while since we’ve seen a good circuit bending hack. This project started as a way to demo the [Tymkrs] “MIDI In Me” kit. A cheap toy keyboard was sacrificed for its sound generator board. Like many cheap mass-produced toys, this board is based upon a COB (chip on board) package. The silicon die of the main ASIC is placed directly on the PCB and bonded out to pads. A round epoxy blob keeps everything protected.

The [Tymkrs] found a number of the chip’s pads were unused in their keyboard. The inputs appeared to trigger drums, possibly for use in a different toy. These inputs, coupled with the ‘demo song’ buttons turned out to be the basis of this hack. MIDI input is sent to a Parallax Propeller. The prop runs a program that will set its I/O pins based upon MIDI Note On/Off commands. The I/O pins then drive transistors which inject signals into the button inputs of the keyboard.

The [Tymkrs] even went so far as to use a voltage divider on the main clock circuit of the keyboard. Changing the main clock causes a sort of pitch bend effect often heard with circuit bent toys. As with the buttons, a MIDI signal commands the prop to enable or disable oscillator signal injection. A potentiometer is used to tweak the oscillator frequency.

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Rekindling Forth with a Propeller Jupiter Ace

Jupiter

The Jupiter Ace was a small membrane keyboard, cassette tape drive computer akin to the ZX Spectrum released in 1982. Priced at £90, it was a little more expensive than its home computer contemporaries, but had a very interesting feature: instead of BASIC, the Ace ran Forth. This interpreted stack-based language is far more capable than the BASIC variants found on home computers of the day, but unfortunately the Ace failed simply because Forth was so foreign to most consumers.

Not wanting to let a good idea die, [prof_braino] is bringing Forth back into the modern age. He’s using a Parallax Propeller to emulate a simple home computer running Forth. Instead of a book-sized computer, the new Propeller version runs on a single chip, with 8 CPU cores running 24 times faster than the original, with 32 times more RAM and an SD card for basically unlimited storage.

Programming a Propeller on an ARM

[Stefan] uses a small ARM-powered netbook for his development work, so when he tried to play around with the Parallax Propeller he ran into a few problems. The official tools from Parallax are Windows only, and the available 3rd party dev tools are only compiled for x86. After a lot of futzing about, [Stefan] was able to develop on his ARM netbook and wrote in to tell us how it’s done.

Luckily, Parallax released a GCC port for the Propeller, but unfortunately isn’t completely portable to ARM. The Propeller loader for this architecture ambivalent build uses a little bit of SPIN code, which can only be compiled on Intel machines.

To get around this problem, [Stefan] wrote an installer script to gather all the necessary bits of code to his computer. His ARM/Linux toolchain consists of the Propeller GCC, an open source SPIN compiler, and a Python script used to load code [Stefan] found on the Propeller forums.

Now that [Stefan] has a complete toolchain for programming the Propeller on an ARM device, it’s possible to develop for this very cool multi-core microcontroller on his netbook or even the Raspberry Pi.

Propeller turned into chiptune player with a software SID

If there wasn’t reason enough to love the Parallax Propeller, now you can listen to chiptunes with your own pocket SID audio player.

This chiptune audio player uses the very unusual and very cool eight-core Parallax Propeller microcontroller. After soldering a few caps and resistors to a Propeller dev board to allow for audio out, the only thing necessary to play SID music files is a bit of code and an SD card breakout.

The key piece of code for this build would be the SIDcog object written by [Johannes Ahlebrand] this piece of code turns one of the eight cores in the Propeller into a virtual version of the classic Commodore 64 sound chip.

Since the SIDcog object only takes up one core on the eight core Propeller, it could be possible to turn this SID player into an all-inclusive chiptune audio source; the addition of an Atari POKEY or FM synthesis cog would allow for just about any conceivable chiptune sound to be carried around in a pocket.

No Hackaday post about chiptunes or SIDs would be complete without an audio demo, so you can check out the Propeller-powered SID after the break.

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Reliving the BBS days with a Propeller

Back before the world wide web, self-proclaimed geeks would get our compute on by dialing in to bulletin board systems. In their heyday, these BBSes were filled with interesting people and warez to fill the most capacious 10 Megabyte hard drive. In an attempt to relive the days of the Internet before the Eternal September, [Jeff Ledger] whipped up a tutorial for dialing up BBSes with an updated classic computer.

Instead of doing this tutorial with a C64 or an Apple II, [Jeff] used the Propeller powered Pocket Mini Computer he designed. This computer features 32Kb of RAM inside an eight-core Parallax Propeller along with a BASIC interpreter to run your own programs.

This Mini Computer can connect to BBS systems, but seeing as how acoustically coupled modems are rare as hen’s teeth these days, [Jeff] thought it would be a good idea to log in to the many Internet connected BBS servers using his desktop as a bridge between the Propeller and the Internet.

After [Jeff] got his Propeller computer up and running on a BBS, he was free to play Trade Wars or slay grues in one of the many MUDs still running. Not bad for a demonstration of the Internet of old, and made even better by the use of a Propeller.

Hackaday Links: June 12, 2012

Amazing 3D rendering in real-time

Ah, the 90s. A much simpler time when the presenters on Bad Influence! were amazed by the 3D rendering capabilities of the SGI Onyx RealityEngine2. This giant machine cost £250,000 back in the day, an amazing sum but then again we’re getting nostalgic for old SGI hardware.

Well, Mega is taken… let’s call it Grande

[John Park] needed to put something together for last month’s Maker Faire. A comically large, fully functional Arduino was the obvious choice. If you didn’t catch the demo last month, you can grab all the files over on Thingiverse.

Is that an atomic clock in your pocket or… oh, I see.

Here’s the world’s smallest atomic clock. It’s made for military hardware, so don’t expect this thing to show up at Sparkfun anytime soon; we can’t even fathom how much this thing actually costs. Still, it’ll be awesome when this technology trickles down to consumers in 10 or 20 years.

Converting a TRS-80 keyboard to USB

[Karl] is working on an awesome project – putting a Raspberry Pi inside an old TRS-80. The first part of the project – converting a TRS-80 keyboard to USB – is already complete. We can’t wait to see this build finished.

 A DIY Propeller dev board

Last week we complained about the dearth of builds using the Parallax Propeller. A few noble tinkerers answered our call and sent in a few awesome builds using this really unique micro. [Stefan]‘s Propeller One is the latest, and looking at the schematics it should be possible to etch a single-sided board for this project. Awesome work and thanks for giving us a weekend project, [Stefan].

Talking resistor calculator speaks component values

If there’s one thing that will surely blind us, its reading resistor color bands. It doesn’t help that red looks exactly like orange, brown and black are indistinguishable, and different component manufacturers – for some reason – don’t use identical paints for coding their resistors. [Jeff] over at Gadget Gangster has been having the same problem, so he built a talking resistor calculator to speak resistor values to him.

The electronics part of the build is extremely simple with just an MCP3208 ADC providing 12 bits of resolution. The software side is where this project really shines. [Jeff] used a Gadget Gangster QuickStart board housing a Parallax Propeller. With 8 cores running in parallel the Propeller is more than enough to run [Phil Pilgrim]‘s software speech synthesizer. When a resistor is connected to the two alligator leads, the Propeller goes through a lookup table and finds a resistor value matching the number coming from the ADC. From there, it’s just sending a string of phonetic text to the speech synthesizer object.

Even though text-to-speech chips have been around for decades now, [Jeff] chose to build his speech synthesis tool with software. It may just be a testament to the power in the Propeller microcontroller, but anything that keeps us from squinting at resistor color bands is alright by us.

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