Building a Keyboard Adapter for an Atari 2600 (and writing BASIC too!)

In this video, I demonstrate and build a small microcontroller device that allows us to use a modern keyboard with an Atari 2600. I show schematics and walk through the build process, as well as discussing some mistakes I made during my design and build. I also give a brief overview of the firmware and present some short demos of the keyboard driving "BASIC Programming" on the Atari 2600!

During final review, I noticed some audio distortion in certain segments only when using a Bluetooth headset at a high volume. I apologize if this is irritating you, but I wasn't able to filter out the noise or identify the cause.

This is a lengthy and technical video, so please feel free to use the timecode links below to skip to areas of interest.

0:00 Intro
2:23 Keyboard controller schematic and operation
3:25 AND gate and decoder implementation
5:37 MCU-only implementation
6:46 Overview and limitations of components
12:37 Close-up view of and purpose of mini-boards
14:13 Assembly montage
18:33 Disclosure of design errors and corrections
22:17 Rationale of MCU pin selection
23:20 Assembled hardware
24:14 Firmware summary
31:00 Demo: Writing a program with a proper keyboard
33:50 Remaining issues with implementation and fixes
37:54 Closing remarks

Github for documents and source code referenced in this video:
https://git.io/JZcZx

"Building a Universal Atari 2600 12-button 'Star Raiders' Controller"
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"Exploring BASIC Programming for the Atari 2600 - Part 1"
   • Exploring BASIC Programming for the A...  

"Exploring BASIC Programming for the Atari 2600 - Part 2"
   • Exploring BASIC Programming for the A...  

General 7805 Voltage Regulator Datasheet:
https://www.electroschematics.com/780...


Music:
"Disco Factory" by Steven Diemer (1991 Action)
http://deepsid.chordian.net/?file=/MU...

Sound Effects:
"The Transformers", Marvel Productions and Sunbow Productions (1984)
https://w.wiki/3Ts$

Schematics and Atari Keyboard Controller Photo from AtariAge
https://www.atariage.com

Arduino Nano Image from Fritzing software
https://fritzing.org

Keyboard Image from Summer Rain
http://getdrawings.com/get-drawing#co...


Products and components used in this video:

Atmega328p Arduino Nano Microcontroller
https://ebay.us/ZISfvs

DB9 Atari/Sega/Commodore Extension Cable
https://ebay.us/pkXT2o

Electronics Project Box
https://ebay.us/hfCkCL

PG7 Cable Gland
https://ebay.us/575eY7

5x7cm Protoboard
https://ebay.us/LTBHqj

DB9 Female-Female Gender Changer
https://ebay.us/juy81Y

Mini Din-6 Female Connector
https://ebay.us/YMTdu4

Male-Female DuPoint Cables
https://ebay.us/dEIRJM