Lightly edited copy of the original blog post from when I was in high school:

This is the PropComp in all its current glory. Future versions will have all this contained in a case under the keyboard, kind of like the Commodore 64, except this will include the screen. The whole computer up and running, although missing it's nice large speakers. Don't SparkFun boxes make the most beautiful cases for any electronics project? They are sturdy and easy to modify, my first choice when prototyping any new creation.

After I received the Parallax Propeller Demo Board for a recent birthday, I've realized that my dream of a mini computer with the look and feel of an early computer from the 90s is easily attainable without the hassle of completing the original CS Project. This micro controller allows code to be extremely rapidly developed and put in place in a hardware system. The original CS Project is currently slowed, but it hasn't been stopped completely. I still want the satisfaction of designing and building a computer from the ground up, this just scratches my itch for a functional retro computer. The following is the plan for this new Prop-based computer:


The basic idea behind my computer that makes it more useful and cool than any other personal device that you can buy today is its versatility. I am in the process of writing software that allows this computer to operate in any way you feel like using it. Don't have a screen? That's fine, just use the keyboard and listen to music and navigate with sound prompts. Don't have a keyboard? The software works with mouse-only.

Any way that you care to configure it, the PropComp can be useful to you. All the software is open-source, so if you have a little time and some programming experience you can customize it to your heart's desire. If I can get developers interested and if I receive enough money in donations it may be possible to start a library of free applications similar to what the iPhone has. But to get that working I need my own domain and money to make the computer as cheap as possible, so head over to the donations section and give me some money (please) :D.


The hardware is very basic at this point. It centers around the Propeller Demo Board, with a simple module for SD Cards. The SD Card module supports almost all available cards and gives more than enough space for apps, music, videos, and documents. Sometime in the future when I have the software developed enough and I have enough money I'll get a dedicated PCB with everything I want built in, but at the moment I am stuck with the demo board. The final product will let me bring the controls out to different spots in the case, the demo board doesn't allow me to do it because all it's input, output, and controls are hardwired with no extra ports to solder to. It is also prohibitively expensive if I started selling these computers to raise money for projects.



To get the apps that are on the SD card into RAM to be executed I need a boot loader that sits in EEPROM and runs every time the computer is turned on. There is already an available project called PropDOS that does this, so I am currently using that. The final version of the computer will have an overhauled version of this bootloader, which is already in development. This new bootloader will have a more intuitive and fast interface for getting apps loaded, while still keeping the features it has that make it so nice.

Feature Applications

Without programs to make it useful the PropComp would be just another development platform and not really worth anything to an average person. That is why I am creating some applications that are built into the computer and make it useful from the start. With these, the usefulness of the computer will already be established and because everything is open-source it will be inherently easy for third-party developers to write apps for it.  Hopefully this will give my computer a competitive edge to make up for abilities that rank far lower than the average cell phone nowadays.

This is the list of the applications that I have planned right now:

  • Calculator: Every computer needs a calculator. The PropCalc is now at version 1.5.
  • Calendar: People like having something that remembers stuff for them. The PropCalendar does this with ease. It is currently at version 1.1.
  • Paint: Back in the early days of computers, when you got bored you whipped out MS paint and drew a picture. PropPaint is now working in VGA mode at version 0.7.
  • Music Player: I have found that the setup of the two music players in PropDOS are not easily used. The HMU player is OK, but you have to type in a command and a long file name each time you want to change the song. The wav player is almost unusable because it has to play the whole file through from start to finish before anything can be accomplished. I am going to make a dedicated music player with a nicer interface using the code from the two music players in PropDOS. Development has currently not begun on this feature.
  • Printer Interface: A text editor already exists, a method of printing out text on a standard printer does not. Development has currently not begun on this feature.
  • Internet Browser: People have shown that it is possible to connect a Propeller to the internet. Hopefully one of these people will let me use their code so I can get a real text-based internet browser working for the PropComp. Development has currently not begun on this feature.
  • Speech Synthesizer: I want the computer to talk. Using a special code object called VocalTract I have accomplished this. It is still basic, but it works. It is version 0.3. Drop any other application suggestions at the provided email, or IM at (handle withheld to protect the innocent).


The Guts!

You can see the Parallax Propeller Demo Board with a semi-crudely taped on and soldered SD module attached to an SD card breakout board from SparkFun and a nice 256MB SD card.

This picture is of the PropComp running PropDOS. I have many programs on the SD card that are in development, and some that I pulled off the internet, along with HMU and WAV type music for my 32 bit listening pleasure.

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