Shared Projects

CC2-32K-EPROM-CARTRIDGE-Version-1-Revision-A-01.06.2013 is a 32K EPROM Cartridge for the Tandy Radio Shack TRS-80 Color Computer 1, 2, 3 and Dragon Data Dragon computers. Notes: The CoCo 1, 2 and Dragon can only access the first 16K. The CoCo 3 can access the entire 32K, minus the 0xFFnn I/O and Vector page. Many other similar (but much improved) cartridges are forthcoming. There are much better designs in my possession and I intend to post them all, in no particular order. There is a GitHub Page here: https://github.com/TheLittleEngineers/CoCoDragon-CC2-32KEC-V1RA - PLEASE NOTE: THIS VERSION HAS NOT YET BEEN TESTED.

Please note: This is derived from an original design by “Little” John Eric and/or his father “Big” John Robert (J.R.) by “Uncle” Robert Allen. It should be thoroughly scrutinized and verified prior to actual use of any kind. DISCLAIMER: The following article is provided for informational purposes only. Any attempt to modify your computer without the proper skills to do so may void your computer. Any attempt to modify your computer without unplugging it first may void you. This Information is provided “as-is” with no guarantee of fitness for any purpose, either explicit or implied. We disclaim any and all responsibility for losses incurred through the use of this information. By using this information, you are deemed to have accepted these conditions of use, and you agree NOT to sue us. CLARIFICATION: The above disclaimer states as plainly as possible that if you decide to make use of any of the information contained within this document that you do so at your own risk. Designing hardware for the CoCo (ColorComputer) and other vintage hardware is a hobby of ours and is not motivated by any desire of profits. As this is a not for profit venture, obviously we can’t afford not to disclaim the use of this information.

CC2-32K-EPROM-CARTRIDGE-2012-Version-1-Revision-A-07.02.2012 is a 32K EPROM Cartridge for the Tandy Radio Shack TRS-80 Color Computer 1, 2, 3 and Dragon Data Dragon computers. Notes: The CoCo 1, 2 and Dragon can only access the first 16K. The CoCo 3 can access the entire 32K, minus the 0xFFnn I/O and Vector page. Many other similar (but much improved) cartridges are forthcoming. There are much better designs in my possession and I intend to post them all, in no particular order. There is a GitHub Page here: https://github.com/TheLittleEngineers/CoCoDragon-CC2-32K-EPROM-CARTRIDGE-2012-V1RA - PLEASE NOTE: THIS VERSION HAS NOT YET BEEN TESTED.

Please note: This is derived from an original design by “Little” John Eric and/or his father “Big” John Robert (J.R.) by “Uncle” Robert Allen. It should be thoroughly scrutinized and verified prior to actual use of any kind. DISCLAIMER: The following article is provided for informational purposes only. Any attempt to modify your computer without the proper skills to do so may void your computer. Any attempt to modify your computer without unplugging it first may void you. This Information is provided “as-is” with no guarantee of fitness for any purpose, either explicit or implied. We disclaim any and all responsibility for losses incurred through the use of this information. By using this information, you are deemed to have accepted these conditions of use, and you agree NOT to sue us. CLARIFICATION: The above disclaimer states as plainly as possible that if you decide to make use of any of the information contained within this document that you do so at your own risk. Designing hardware for the CoCo (ColorComputer) and other vintage hardware is a hobby of ours and is not motivated by any desire of profits. As this is a not for profit venture, obviously we can’t afford not to disclaim the use of this information.

This is a 512K RAM Upgrade for the Tandy Radio Shack TRS-80 Color Computer 3 that features battery backup. There is a GitHub Page Here: https://github.com/TheLittleEngineers/CC3-512KSRAM-V1R03 - PLEASE NOTE: THIS VERSION HAS NOT YET BEEN TESTED.

Please note: This DESIGN should be thoroughly scrutinized and verified prior to actual use of any kind. DISCLAIMER: The following article is provided for informational purposes only. Any attempt to modify your computer without the proper skills to do so may void your computer. Any attempt to modify your computer without unplugging it first may void you. This Information is provided “as-is” with no guarantee of fitness for any purpose, either explicit or implied. We disclaim any and all responsibility for losses incurred through the use of this information. By using this information, you are deemed to have accepted these conditions of use, and you agree NOT to sue us. CLARIFICATION: The above disclaimer states as plainly as possible that if you decide to make use of any of the information contained within this document that you do so at your own risk. Designing hardware for the CoCo (ColorComputer) and other vintage hardware is a hobby of ours and is not motivated by any desire of profits. As this is a not for profit venture, obviously we can’t afford not to disclaim the use of this information.

The “CC3-MPI-26-3124-Satellite-Board-CoCo-3-Upgrade-2009-V1RA” is a clone of the “Part # AXX-7119 Satellite Board for 26-3124” Multi-Pak Interface CoCo 3 upgrade with the additional feature of being switchable between CoCo 1, 2 or 3 mode. Installation instructions are available at the GitHub Page: https://github.com/TheLittleEngineers/CC3-MPI-26-3124-Satellite-Board - PLEASE NOTE: THIS VERSION HAS NOT YET BEEN TESTED.

Please note: This is derived from an original design by “Little” John Eric and/or his father “Big” John Robert (J.R.) by “Uncle” Robert Allen. It should be thoroughly scrutinized and verified prior to actual use of any kind. DISCLAIMER: The following article is provided for informational purposes only. Any attempt to modify your computer without the proper skills to do so may void your computer. Any attempt to modify your computer without unplugging it first may void you. This Information is provided “as-is” with no guarantee of fitness for any purpose, either explicit or implied. We disclaim any and all responsibility for losses incurred through the use of this information. By using this information, you are deemed to have accepted these conditions of use, and you agree NOT to sue us. CLARIFICATION: The above disclaimer states as plainly as possible that if you decide to make use of any of the information contained within this document that you do so at your own risk. Designing hardware for the CoCo (ColorComputer) and other vintage hardware is a hobby of ours and is not motivated by any desire of profits. As this is a not for profit venture, obviously we can’t afford not to disclaim the use of this information.

A simple buffer pack for the CoCo/Dragon/Clones. All signals are buffered except for the 5V and 12V Supplies, SND and SLENB*. Designed by: “The R.A.T.” May 21, 2019. LICENSE: CC BY-SA 4.0. I decided that, if I was going to be plugging untested prototypes into my CoCo, I needed to provide at least some protection against frying the poor thing. This is the result of that “protection effort”. - PLEASE NOTE: THIS VERSION HAS NOT YET BEEN TESTED. There is a GitHub Page Here: https://github.com/TheLittleEngineers/CoCoDragonBufferPak-V1R0

Please note: This DESIGN should be thoroughly scrutinized and verified prior to actual use of any kind. DISCLAIMER: The following article is provided for informational purposes only. Any attempt to modify your computer without the proper skills to do so may void your computer. Any attempt to modify your computer without unplugging it first may void you. This Information is provided “as-is” with no guarantee of fitness for any purpose, either explicit or implied. We disclaim any and all responsibility for losses incurred through the use of this information. By using this information, you are deemed to have accepted these conditions of use, and you agree NOT to sue us. CLARIFICATION: The above disclaimer states as plainly as possible that if you decide to make use of any of the information contained within this document that you do so at your own risk. Designing hardware for the CoCo (ColorComputer) and other vintage hardware is a hobby of ours and is not motivated by any desire of profits. As this is a not for profit venture, obviously we can’t afford not to disclaim the use of this information.

CC-FlexiMIDI-V1R1-03.09.2009 - A Hardware M.I.D.I. Interface Program Pak Cartridge for the Tandy Radio Shack TRS-80 Color Computer 1, 2 and 3, including clones and compatibles (Tano Dragon 64, Dragon Data D32, D64 and D200, Tandy Data Products TDP-100, etcetera). There is a GitHub Page Here: https://github.com/TheLittleEngineers/CoCoDragonFlexiMIDI-V1R1 - PLEASE NOTE: THIS VERSION HAS NOT YET BEEN TESTED.

Please note: This is derived from an original design by “Little” John Eric and/or his father “Big” John Robert (J.R.) by “Uncle” Robert Allen. It should be thoroughly scrutinized and verified prior to actual use of any kind. DISCLAIMER: The following article is provided for informational purposes only. Any attempt to modify your computer without the proper skills to do so may void your computer. Any attempt to modify your computer without unplugging it first may void you. This Information is provided “as-is” with no guarantee of fitness for any purpose, either explicit or implied. We disclaim any and all responsibility for losses incurred through the use of this information. By using this information, you are deemed to have accepted these conditions of use, and you agree NOT to sue us. CLARIFICATION: The above disclaimer states as plainly as possible that if you decide to make use of any of the information contained within this document that you do so at your own risk. Designing hardware for the CoCo (ColorComputer) and other vintage hardware is a hobby of ours and is not motivated by any desire of profits. As this is a not for profit venture, obviously we can’t afford not to disclaim the use of this information.

PCB for connect TI TMP117 high precision sensor to Raspberry Pi Zero W. This is part of Open Source project https://github.com/shodanx/LXI-Instruments-DataLogger

Note: Order that board with Flex option!

• Plugs into: B-5971 Nixie Tube SmartLink (Board 2of3)
• Replaces SK-136 Socket (If you don’t have the 14 pin socket)
• Also requires: B-5971 SmartSocket Driver (Board 3of3)
• Project Files: B-5971_SmartSocket.zip
• More Info: Neonixie-L Google Group
• More Info: Smartsockets Yahoo Group

• Plugs into: B-5971 Nixie Tube SmartLink (Board 2of3)
• Accepts SK-136 Socket (If you already have the 14 pin socket)
• Also requires: B-5971 SmartSocket Driver (Board 3of3)
• Project Files: B-5971_SmartSocket.zip
• More Info: Neonixie-L Google Group
• More Info: Smartsockets Yahoo Group

• Plugs into B-5971 SmartSocket Driver (Board 3of3) at 90°
• Also requires:
• • SmartSocket TypeA (Board 1of3) or
• • SmartSocket TypeB (Board 1of3)
• Project Files: B-5971_SmartSocket.zip
• More Info: Neonixie-L Google Group
• More Info: Smartsockets Yahoo Group

• Plugs into: B-5971 SmartSocket SmartLink (Board 2of3)
• Based on B-7971 V2 - Chris/fixitsan2
• PIC16F690 Running SmartSocket Code (in project files)
• Project Files: B-5971_SmartSocket.zip
• More Info: Neonixie-L Google Group
• More Info: Smartsockets Yahoo Group

B-5971 SmartSocket Assembly

LM399AH reference project https://misrv.com/diy-lm399ah/

Low input bias current buffer for Julie Research Labs VDR 106/107. The mounting holes are sized to fit directly on the JRL divider. LTC1052 is first stage, OPA634 provides high output drive. There is JFET protection on the inputs.

Board is powered by +5V, which feeds ADP5071, providing +16V & -8V supplies.

see https://www.eevblog.com/forum/metrology/buffer-for-kelvin-varley-divider-185532/

SociaLite LED Board

Breadboard Coin Cell Adapter, RevA

Modified MCU power and ground connections to get them further away from the edge, note the reduced sizes of unused pins along the board edge