Building a Retro Synthesizer with the Pocket Mini Computer by Propellerpowered
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SIDSynth.jpg
Got a MIDI keyboard with a MIDI-OUT jack?  

This Instructable will show you how to create a "retro sounding" synthesizer using your Pocket Mini Computer.



I'm a huge fan of the Commodore 64.  One of it's most memorable characteristics is the sound of it's 3 voice SID chip.   Most Xgeners will recognize it's unique sound from old school videos games like Commando or MULE.   The Pocket Mini Computer has access to an excellent emulation of the SID chip, called SIDcog, used extensively in this project.    

Ready to rock out with a SID Synth?   Read on!

Requirements: 
  • The Pocket Mini Computer (see next page for details)
  • Breadboard or "perf" board.
  • 2 - 220ohm resistors
  • 1 - 4.7k resistors
  • 1 - 6N138 Optocoupler
  • 1 - 1N914 Signal Diode

I've included schematics and links to all sources so you can build and expand on this project to your hearts content.


 
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Step 1: What is the Pocket Mini Computer?

Pocket Computer.jpg
You might be scratching your head at the requirement of a Pocket Mini Computer.

What's a Pocket Mini Computer?    I'm glad you asked!


The Pocket Mini Computer is an open source "mini computer" design which uses the Parallax Propeller microcontroller as it's brain.   The kit from Propellerpowered.com comes pre-loaded with a retro-style BASIC.  The hardware itself is extremely powerful & featured. 

The Pocket Mini Computer hardware specifications:
  • Parallax Propeller Quickstart Board (8 cogs, 32K RAM, 64K EEPROM)
  • Improved VGA Output
  • Stereo R/L Audio Output
  • PS/2 Keyboard/Mouse Input
  • Wii(tm) compatible controller connection
  • Optional microSD adapter connector
  • Optional iR connector
  • Experimenter's port

The Pocket Mini Computer is language compatible with Spin, Assembly (PASM), C, and BASIC.

COLOR BASIC features:
  • 4094 available bytes free
  • 64 colors
  • 1 "SIDlike" audio channel
  • 127 character re-programmable character set
  • plot, line, and box graphics commands
  • I/O access commands
  • 95+ BASIC Commands, operators, and functions
  • SD operating system
  • Full screen editor (requires a microSD card.)
  • Ability to execute non-basic binary programs
  • Extended memory features (requires a 23K256 SRAM chip)

More details about the Pocket Mini Computer can be found on this Wiki. 
Schematics and Souce Code are avaible for anyone who wants to "roll their own".





poofrabbit says: Nov 29, 2012. 8:42 PM
Congratulations on being a finalist in the DIY Audio Contest!! Good luck to you!
sonicase says: Oct 20, 2012. 2:56 AM
pretty cool

i found it a little commercial-ish but the project is still pretty good
and the kit is reasonably priced considering it includes the quickstart board
.. very tempting to buy

if i'm not mistaken, i think this could be done with just the quickstart board and midi optoisolator circuit right? you would just have to load the sidsynth on before hand... or am i wrong? i haven't worked with the board.
Propellerpowered (author) says: Oct 20, 2012. 8:26 AM
Using the Pocket Mini Computer in this project makes it easier to use the right/left channel audio circuit also used for audio output on this project.
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