Color Computer Projects

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7/11/2000 - Welcome to the projects page. Here you'll find hardware projects of varying degrees of difficulty and usefulness. Some things I plan to include: schematics of the Tandy hi-res adapter, joystick selector switchbox, lots of 'repack' info, much more...


Repack Page

My CoCo 3 in an AT case.

CoCo3P

My portable CoCo 3 with internal floppy. Runs off 12vdc

How to power your CoCo3 with 12 volts DC


Marty Goodman's DC Modem Pak to RS-232 Pak conversion.

Convert the Tandy Direct Connect Modem Pak into an RS-232 Pak. Thanks to Ray watts for the Rainbow scans!


CoCo Turbo Light

See when your CoCo is operating at high speed.


CoCo1 composite video

Add composite output to your CoCo1.
PC board shown 'pretty close to actual size'.
Dark gray circles are holes for zip-tie to hold co-axial cables to the board.


CoCo repack adapter

joystick, cassette, RS-232



Disk Drive power LED

click for larger image

I don't know how many times I forgot to turn off my CoCo and/or the external drive bay, leaving them cooking over night. A power LED was one of the first things I added to my CoCo after the warranty expired.

I'm a big fan of making things look as professional as possible... making it look like it came from the factory that way... so when it came to adding a power indicator to the external drive bay, I didn't want to drill any holes in the case. I had some 2-color LED's in my parts bin and figured out a beautiful solution. A green LED to indicate power, which turns red when the drive is in use.

The first thing you'll need is a 2-color LED that physically matches the LED in your floppy drive. Mine was a standard T-1 3/4, very easy to locate. You'll also need a 7404 inverter. I put mine on a small circuit board which fit neatly on the back of my floppy drive. A 330 ohm ¼ watt resistor, some wire (the wire-wrapping kind works well) and some small heat-shrink tubing complete the list

Carefully disassemble the floppy drive to the extent necessary to extract the original LED. If you don't want to desolder it, you can cut the leads. One lead of the original LED is the control line, which needs to be wired to the circuit. Since floppy drives are not all the same, you may have to try them one at a time to get the right one. If you can access the LED with a voltmeter while accessing the floppy drive, you will see that one side of the LED stays constant and the other side changes voltage. This is the line that controls our 2 color LED.

Now put the 2 color LED in place of the original and run wires from the LED leads and the control line from the floppy drive back to the inverter chip. Make sure all the leads are insulated... wouldn't want to short anything out. Connect the wires to the circuit in accordance with the schematic. You can get the +5v and GND from right behind the power connector.

Reassemble everything and you're ready for a 'smoke' test. If you turn it on and no smoke comes out, you done good. If everything works right, you done great!
If your LED is red and turns green when the drive is accessed, reverse the LED's connections to the inverter.
If you have a three prong LED, the common lead goes to the resistor to ground and the other two leads go to the inverter.

Another great use for one of your unused inverters is to let you invert the Side-Select line and use a switch to toggle between normal and inverted signal. This basically lets you flip your disk over without removing it from the drive. Great for 2-disk games like Carmen SanDiego or Microscopic Mission. Also great because it works regardless of OS!


Atari/Commodore joystick adapter

Here's a fun and easy project I've loved using with my CoCo. This adapter was designed to interface an Atari(or C64) style joystick to you CoCo. This is great for games like Zaxxon or Ghana Bwana, where analog controllers are sometimes too sensitive. I left the Atari connector out of the schematic so you can also easily convert a dusty PC gamepad or nearly any "digital" (meaning on/off switches as opposed to analog 0-5v) joystick. I attached an Atari joystick cable to an old Nintendo gamepad, plugged into this circuit to plug into my CoCo. Talk about a Frankenstein setup!

click for larger image

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~~~Stay tuned!~~~last updated 12/13/02