![How to use a Quadrature Rotary Encoder with an Altera MAX CPLD?…& Jurassic Park? [#66] @BehindTheCode_wGerry](https://i.ytimg.com/vi/rHK6jUrP6DA/maxresdefault.jpg)
Uploaded January 2026 | Updated September 2026, 2 weeks ago
In this video I show you how to interface a Quadrature Rotary Encoder to an Altera MAX EPM7128SLC84 CPLD logic device from 1998. We implement a Quadrature decoder circuit within the CPLD using the Graphical design entry form. Once the circuit is built, we perform a practical test on an Altera PLDT-2 development board and read the logic pulses generated by two separate rotary encoders. We then display the counted pulses on a dual 7-segment display housed on the dev board.
Now I intentionally changed my circuit slightly in Quartus compared to the practical demo. This change would alter the displayed maximum number. Can you spot what I changed? Hehe! A Fantastic interfacing project. :)D
I also talk about a Digital apparatus that was built for the film Jurassic Park in the early 90's by members of ILM, Tippett Studios and Pixar. This device was called the D.I.D. or "Dinosaur Input Device". This was a puppet motion capture system, and it used the same type of Quadrature rotary encoders as we were testing in this video. (Bourns Rotary encoders)
bourns.com/docs/Product-Datasheets/ENC1J.pdf
The electronics and computer interface for the "D.I.D." was built by Craig Hayes of Tippett Studio's. You can read an amazing in depth article on the Dinosaur Input Device at the link below:
vfxblog.com/dinosaurinputdevice
===========================================================
Image Credits are listed below:
Craig Hayes Full Scale ED-209 Robot - Robocop Film (1987)
vfxvoice.com/robocop-crashes-30-ed-209-still-a-stop-motion-hero
D.I.D. Full Article:
vfxblog.com/dinosaurinputdevice
Softimage Interface:
https://cupoftea.social/@jon/110868667871329721
Mark Dippé, Eric Armstrong and Steve Williams(Spaz) with Muren in the Pitt at ILM: theasc.com/articles/dennis-muren-asc
Jurassic Park 1993 Movie Cover:
gatewayfilmcenter.org/movies/jurassic-park-1993
Dinosaur Input Device Photos - Sean Charlesworth Dynamics:
https://x.com/CworthDynamics/status/1240753527489572864?s=20
Dinosaur Input Device - Academy Museum of Motion Pictures
academymuseum.org/en/collection/stop-motion-capture-device
Phil Tippett Online Auction - Dinosaur Input Device and Terminal
propstore.com/product/jurassic-park-1993/dinosaur-input-device-and-terminal
==========================================================
Want to help support my work?
Become one of my dedicated Supporters:
behindthecode.ca/become-a-supporter
Follow me here:
https://linktr.ee/BehindTheCode_wGerry
******************************************************************************
Thanks for visiting Behind The Code with Gerry!
******************************************************************************
#electronics #engineering #cpld #altera #fpga #retrogaming #gamedev #flashcart #nintendo #gamedevelopment #videogames
In this video I show you how to interface a Quadrature Rotary Encoder to an Altera MAX EPM7128SLC84 CPLD logic device from 1998. We implement a Quadrature decoder circuit within the CPLD using the Graphical design entry form. Once the circuit is built, we perform a practical test on an Altera PLDT-2 development board and read the logic pulses generated by two separate rotary encoders. We then display the counted pulses on a dual 7-segment display housed on the dev board.
Now I intentionally changed my circuit slightly in Quartus compared to the practical demo. This change would alter the displayed maximum number. Can you spot what I changed? Hehe! A Fantastic interfacing project. :)D
I also talk about a Digital apparatus that was built for the film Jurassic Park in the early 90's by members of ILM, Tippett Studios and Pixar. This device was called the D.I.D. or "Dinosaur Input Device". This was a puppet motion capture system, and it used the same type of Quadrature rotary encoders as we were testing in this video. (Bourns Rotary encoders)
bourns.com/docs/Product-Datasheets/ENC1J.pdf
The electronics and computer interface for the "D.I.D." was built by Craig Hayes of Tippett Studio's. You can read an amazing in depth article on the Dinosaur Input Device at the link below:
vfxblog.com/dinosaurinputdevice
===========================================================
Image Credits are listed below:
Craig Hayes Full Scale ED-209 Robot - Robocop Film (1987)
vfxvoice.com/robocop-crashes-30-ed-209-still-a-stop-motion-hero
D.I.D. Full Article:
vfxblog.com/dinosaurinputdevice
Softimage Interface:
https://cupoftea.social/@jon/110868667871329721
Mark Dippé, Eric Armstrong and Steve Williams(Spaz) with Muren in the Pitt at ILM: theasc.com/articles/dennis-muren-asc
Jurassic Park 1993 Movie Cover:
gatewayfilmcenter.org/movies/jurassic-park-1993
Dinosaur Input Device Photos - Sean Charlesworth Dynamics:
https://x.com/CworthDynamics/status/1240753527489572864?s=20
Dinosaur Input Device - Academy Museum of Motion Pictures
academymuseum.org/en/collection/stop-motion-capture-device
Phil Tippett Online Auction - Dinosaur Input Device and Terminal
propstore.com/product/jurassic-park-1993/dinosaur-input-device-and-terminal
==========================================================
Want to help support my work?
Become one of my dedicated Supporters:
behindthecode.ca/become-a-supporter
Follow me here:
https://linktr.ee/BehindTheCode_wGerry
******************************************************************************
Thanks for visiting Behind The Code with Gerry!
******************************************************************************
#electronics #engineering #cpld #altera #fpga #retrogaming #gamedev #flashcart #nintendo #gamedevelopment #videogames
![How to use a Quadrature Rotary Encoder with an Altera MAX CPLD?…& Jurassic Park? [#66]](https://i.ytimg.com/vi/rHK6jUrP6DA/mqdefault.jpg "How to use a Quadrature Rotary Encoder with an Altera MAX CPLD?…& Jurassic Park? [#66]
In this video I show you how to interface a Quadrature Rotary Encoder to an Altera MAX EPM7128SLC84 CPLD logic device from 1998. We implement a Quadrature decoder circuit within the CPLD using the Graphical design entry form. Once the circuit is built, we perform a practical test on an Altera PLDT-2 development board and read the logic pulses generated by two separate rotary encoders. We then display the counted pulses on a dual 7-segment display housed on the dev board.
Now I intentionally changed my circuit slightly in Quartus compared to the practical demo. This change would alter the displayed maximum number. Can you spot what I changed? Hehe! A Fantastic interfacing project. :)D
I also talk about a Digital apparatus that was built for the film Jurassic Park in the early 90s by members of ILM, Tippett Studios and Pixar. This device was called the D.I.D. or Dinosaur Input Device. This was a puppet motion capture system, and it used the same type of Quadrature rotary encoders as we were testing in this video. (Bourns Rotary encoders)
https://www.bourns.com/docs/Product-Datasheets/ENC1J.pdf
The electronics and computer interface for the D.I.D. was built by Craig Hayes of Tippett Studios. You can read an amazing in depth article on the Dinosaur Input Device at the link below:
https://vfxblog.com/dinosaurinputdevice/
Image Credits are listed below:
Craig Hayes Full Scale ED-209 Robot - Robocop Film (1987)
https://vfxvoice.com/robocop-crashes-30-ed-209-still-a-stop-motion-hero/
D.I.D. Full Article:
https://vfxblog.com/dinosaurinputdevice/
Softimage Interface:
https://cupoftea.social/@jon/110868667871329721
Mark Dippé, Eric Armstrong and Steve Williams(Spaz) with Muren in the Pitt at ILM: https://theasc.com/articles/dennis-muren-asc
Jurassic Park 1993 Movie Cover:
https://gatewayfilmcenter.org/movies/jurassic-park-1993/
Dinosaur Input Device Photos - Sean Charlesworth Dynamics:
https://x.com/CworthDynamics/status/1240753527489572864?s=20
Dinosaur Input Device - Academy Museum of Motion Pictures
https://www.academymuseum.org/en/collection/stop-motion-capture-device
Phil Tippett Online Auction - Dinosaur Input Device and Terminal
https://propstore.com/product/jurassic-park-1993/dinosaur-input-device-and-terminal/
Want to help support my work?
Become one of my dedicated Supporters:
https://www.behindthecode.ca/become-a-supporter/
Follow me here:
https://linktr.ee/BehindTheCode_wGerry
******************************************************************************
Thanks for visiting Behind The Code with Gerry!
******************************************************************************
#electronics #engineering #cpld #altera #fpga #retrogaming #gamedev #flashcart #nintendo #gamedevelopment #videogames")
![Connecting my N64 Console to an FPGA over the Joystick Port [#6]](https://i.ytimg.com/vi/rKU0B4scPDM/mqdefault.jpg "Connecting my N64 Console to an FPGA over the Joystick Port [#6]
NOTE: This Video was re-uploaded due to a re-edit.
In this Video, I explain and give a demo on an N64 interfacing project which I worked on many years ago.
I wrote some FPGA code in VHDL that receives the serial signals from an N64 console, from one of the Joystick ports. (Port#4 for my Project) It then translates this N64 Serial protocol into ASCII Hex Data. The data can then be sent to an LCD display, or potentially to an RS-232 computer Serial Port, and displayed on an MS-DOS Hyper-terminal session using a program like PUTTY.
I also programmed a custom N64 ROM that runs on an N64 Flashcart to drive the serial signals I want, out to the serial Joystick ports. (AKA JOYBUS ports). This is implemented using DMA transfers to load HEX data into ram, and then writing directly to the N64 PIF chip registers. This allows us to Send/Receive signals to and from the N64 Joystick ports.
I hope you all can enjoy this old N64 interfacing project of mine. This was loads of fun.
NOTE:
*************************************************************************************
JOIN the N64 Development Chat Group N64Brew on Discord at the Link below:
https://discord.gg/nHjbc9d *************************************************************************************
Want to help support the work I am doing?
Say Thanks: https://paypal.me/ThanksGerry
or
Become one of my dedicated SUPPORTERS
https://www.behindthecode.ca/become-a-supporter/
*************************************************
Thanks for visiting Behind The Code with Gerry!
*************************************************
#n64 #gamedev #fpga #vhdl #retrogaming #electronics #computerscience #engineering #computer #nintendo")
![Sega Genesis Development Flash cartridge REV D by Western Technologies - Game DevKit [#29]](https://i.ytimg.com/vi/sZF-Q0_HCXU/mqdefault.jpg "Sega Genesis Development Flash cartridge REV D by Western Technologies - Game DevKit [#29]
In this video I provide a Full in-depth hardware and software DEMO of a 32Mbit Sega Genesis/Mega Drive development Card REV D released by the company Western Technologies Inc. In 1993. I go over a Simple ROM loader program, as well as a Software Debugger. I then review some Sega Genesis source code for a simple Hello World demo program and go over the compiling process using the SIERRA C cross-compiler using a DOS batchfile.
This development cartridge allowed developers to load Sega ROMS under development into the SRAM memory of the cartridge, using an LPT Parallel Printer cable connected to an IBM PC compatible computer.
A simple DOS based command line tool was provided to load ROM files directly from the Development PC. The unit also came with a Full blown SEGA branded 68K software Debugger, which also ran under MS-DOS. It provided a Disassembly window, memory Dump to view HEX data, as well as a Register view section. You could even set Breakpoints and access specialized VDP Register and RAM memory controls.
This unit was quite sophisticated for its time, and is for sure a fantastic development tool for developers and Hobbyists writing their own Homebrew.
This is definitely a Rare and unique item that is highly sought after by collectors.
Hope you all enjoyed this Hardware Demo Folks!
Cheers!
Gerry
Want to help support the work I am doing?
Say Thanks: https://paypal.me/ThanksGerry
or
Become one of my dedicated SUPPORTERS
https://www.behindthecode.ca/become-a-supporter/
******************************************************************************
Thanks for visiting Behind The Code with Gerry!
******************************************************************************
#sega #gamedev #retrogaming #megadrive #genesis #electronics #computerscience #fpga #engineering")
![NEW Game Development Kit pickup +Gameboy Botball +Project Ideas (Dinosaur Input Device) [#46]](https://i.ytimg.com/vi/tTrxtn1a3aE/mqdefault.jpg "NEW Game Development Kit pickup +Gameboy Botball +Project Ideas (Dinosaur Input Device) [#46]
In this video I give a brief Show-N-Tell of a new Game development kit I recently acquired. An SNK Neo Geo Pocket development kit, as well as some rather unusual videogame related hardware. (A Gameboy Advance XBC -XPORT custom cartridge for robotics Botball competitions & a Super Nintendo Gateway game controller.)
I also talk about an upcoming video series I plan on posting here on my channel for all of the Nintendo 3DS related development hardware I have acquired...and my plans to demo both the hardware and software.
Lastly I talk about a very interesting device called a Dinosaur Input Device or D.I.D. This device was custom made by the company ILM for the film Jurassic Park back in the early 90s. I talk about the hardware and plans to build a very simplified version of this device to demo here on my channel.
Want to help support the work I am doing?
Say Thanks: https://paypal.me/ThanksGerry
or
Become one of my dedicated SUPPORTERS
https://www.behindthecode.ca/become-a-supporter/
******************************************************************************
Thanks for visiting Behind The Code with Gerry!
******************************************************************************
#NeoGeo #retrogaming #gamedev #flashcart #nintendo #gamedevelopment #videogames #electronics #engineering")
![How I Turned My Electronics Lab Completely Upside down! [#70]](https://i.ytimg.com/vi/tavqzo39Ty0/mqdefault.jpg "How I Turned My Electronics Lab Completely Upside down! [#70]
The lab is a complete disaster! and I wasnt sure I was going to be able to make a video for you all this week. However, I decided that I may as well bring you all along on this endeavor I decided to tackle today.
I decided to relocate my main computer workstation up to the main floor in my home. Doing this would provide me with more room in the workshop/Lab to work on hardware and projects. It will be a huge improvement and Im sure it will help with my overall day to day progress!!
Other Links mentioned in this Video:
Robots from 1996 used Quadrature Encoders? [#67]
https://youtu.be/1fNEkP3bPI8
Visit Gerrys MERCH page:
https://www.behindthecode.ca/merch-collection/
Want to help support my work?
Visit the Link below:
https://www.behindthecode.ca/become-a-supporter/
Follow me here:
https://linktr.ee/BehindTheCode_wGerry
******************************************************************************
Thanks for visiting Behind The Code with Gerry!
******************************************************************************
#electronics #engineering #programming #maker #microcontrollers #FPGA #CPLD #altera #embeddedsystems #retrogaming #gamedev #videogames")
![N64 Programming PRIMER - PART-5 - THREADS (SDK Lights DEMO) Tutorial [#21]](https://i.ytimg.com/vi/top_rmHZ0UY/mqdefault.jpg "N64 Programming PRIMER - PART-5 - THREADS (SDK Lights DEMO) Tutorial [#21]
NOTE: This Video was re-uploaded due to a re-edit.
********************** ATTENTION **************************
This is PART#5 of my overall N64 Programming Primer Series...however it is
Part-2 of us covering the LIGHTS Demo. I will make this clearer in future Demos.
Apologies for the confusion.
*************************************************************
(Lights DEMO Part #2)
In this video tutorial we are going over one of the LibUltra SDK Demos...that being the LIGHTS demo. In this part two, we talk about n64s use of what they call THREADS and how they help prioritize function execution in your game. This is make sure all data being processed for your game, like graphics and audio etc.. is ready for when the N64 processors require it.
For further reading on the topic of THREADS check out the online N64 manual at the link below:
https://ultra64.ca/files/documentation/online-manuals/man/kantan/step2/index1.html
If you need some help installing the N64 SDK and Libraries onto your Windows PC, there is a Video on YouTube you can watch that will guide you through this process....but read this note below first:
NOTE: Use this disk image link posted below instead of the one in the video. Reason to use this one is because it includes all the updated bells and whistles like demos and other assets. So special Thanks to the Folks over at N64Brew Discord channel for putting this image together:
https://mega.nz/#!AOYDkSxA!MuAqt8iRBk0GGbaqaXVYB9tfZxsquKg5QkbCRL3VOLM
Installing the N64 SDK - VIDEO LINK:
https://youtu.be/84wk0mZ8gfM
*************************************************************************************
Please JOIN the N64 Development Chat Group N64Brew on Discord at the Link below:https://discord.gg/nHjbc9d
*************************************************************************************
Want to help support the work I am doing?
Say Thanks: https://paypal.me/ThanksGerry
or
Become one of my dedicated SUPPORTERS
https://www.behindthecode.ca/become-a-supporter/
Want to help support the work I am doing?
Become one of my dedicated SUPPORTERS
https://www.behindthecode.ca/become-a-supporter/
******************************************************************************
Thanks for visiting Behind The Code with Gerry!
******************************************************************************
#N64 #gamedevelopment #gamedev #retrogaming #megadrive #genesis #electronics #computerscience #fpga #nintendo #computer #computers #PARTNERN64 #N64Dev")
![Want a Grand Tour of my New Electronics LAB? [#43]](https://i.ytimg.com/vi/u80AXA3nvjo/mqdefault.jpg "Want a Grand Tour of my New Electronics LAB? [#43]
In this video I give you a Tour of my New Electronics Lab.
I start off with a brief update on my reverse Engineering work for the Acclaim ArtSend development cartridge used with N64 game development. (Primarily the TUROK series of Games.) This was a proprietary dev cart that used a SCSI interface port, and was designed to be interfaced with the DrV64 backup units released by BUNG Enterprises.
I then move on and show some of the different filming equipment I use, as well as show off the many Work benches in the Lab.
We also get to see a programming Demo of my CRS Plus A250 Robotic arm unit. Following this, we get a look at some of the Game Dev hardware on my bench. I finally close off the video with a look at my Soldering/Test station.
An SGI ONYX Super computer also makes a brief appearance at the tail end of the video. :P
END
Want to help support the work I am doing?
Say Thanks: https://paypal.me/ThanksGerry
or
Become one of my dedicated SUPPORTERS
https://www.behindthecode.ca/become-a-supporter/
******************************************************************************
Thanks for visiting Behind The Code with Gerry!
******************************************************************************
#SGI #retrogaming #gamedev #SEGA #flashcart #nintendo #gamedevelopment #videogames #electronics #engineering #software #SGI")
