Tuesday, October 5, 2021

Lego Lighting braindump (for Rochester Maker Faire 2021)

For this year's Rochester Maker Faire, I'm going to be showing off a couple things related to lighting up Lego stuff.  This post is just meant to show where I am with the two things (for now) that I'll be showing off and what's left to do.  This year, I will be showing off stuff in the "dark room". I've wanted to do something back there for a while, and without Interlock or RLUG exhibiting this year, and at Dan's suggestion, it seemed like a perfect time to do it!

Spaceship Earth lit with LEDs

This one is setting up an "SS Micro" Arduino (my favorite 'ardy form factor) to drive a handful of tiny neopixels to simulate the nighttime illumination of Spaceship Earth in EPCOT.  This is based on @BenBuildsLego's EPCOT design.  Buy his instructions, they're great!

Currently, I have everything as seen above.  The model is essentially complete, and the arduino code is written with a LED strand "scene" concept.  I've started to add a few transitions to go between scenes, randomize them, etc.  Here's the current TODO list for it:

  • Add illumination for Mickey
  • Add illumination (and update the baseplates) for the fountain to be lit up
  • More decoration around SSE
  • Redo the wiring to be less conspicuous - replace the servo wiring with kynar/wire wrap wire
  • New version of the light mounts?
Now, that all said, everything as it is now is sufficient to be exhibited, the above are all icing. :D

Projection Mapping on the Mini Disney Castle

After seeing this done with the fullsized castle, I had to do it for myself on my "Mini Disney Castle", set #40478.  I tried it with the same source video, and it has promising results. There are a few issues with it that I can fix by Maker Faire.
  • The proportions differ a little from the real Cinderella castle slightly, and do not include the side walls.  
    • I need to buy a second MDC and use it for parts to adjust the model to fit the one in the video properly.
    • Until they're back in stock, I can mock up the additions using Lego elements I already have.
  • Video needs to be edited
    • about 70% through, there's a slight jostling where everything shifts by a few pixels
    • There is no fadeout at the end, so that needs to be done
    • or remove the fadein from the beginning so it just runs forever.
  • Playback device needs to be figured out. 
    • Perhaps a Pi connected directly to the DLP, that launches OMXPlayer or VLC on boot, with looping?
  • Need to figure out a good tabletop + back screen system that's easily reproducable rather than the quick test seen in the photo above.  
    • I need to be able to just plop everything down at MakerFaire without needing to spend lots of time to tweak things endlessly.
    • The geometries need to be 100% figured out and perfected before then.
  • Try my other DLPs for best fit
    • The above is with my Dell Short-Throw projector, which means it can be closer, and the background will be larger, which is really nice
    • The BenQ projectors might have better results though and need to be tested.
    • Perhaps figure out all of the geometries for both projectors and bring one as a backup, since they're all self-refurbed anyway.  (leave the backup(s) in the car)

Saturday, October 2, 2021

RetroChallenge 2021-10 intentions (RC2014 Projects Braindump)

Hi all.  So I've decided to settle on working on various RC2014-based projects for this RetroChallenge.  I have a few related projects that I'm kind of in the middle of and have set aside for various reasons... the primary of which being my "ooh... shiny!" reason, where I get pulled off existing projects to start something else thanks to my brain.  ;)

Most of my RC2014 projects are all intertwined so it makes sense to kinda work on all or each of them simultaneously...

Anyway, here's a few things I'd like to work on this month:

"Lego Brick" RC2014

This is my main RC2014 system.  The display on it somehow developed a weird glitch on it that looks like Lichtenberg lightning print.  
I have a spare LCD panel that I can swap into place, i just haven't done it yet.  

Llama Vampire-Storage system (LLVS)

This is my "storage over serial" system that I started working on in the past.  It basically uses something like ANSI escape sequences over your serial console to do disk accesses. It could eventually be used for other devices as well like network and printer access, reatime clock, GPIO, etc.

Eventually, it would be great to have the LLVS "type in" a BASIC program that is a simple bootloader that will load in a custom CP/M kernel with  LLVS routines, so that a super cheap (and slow) CP/M system can be booted without boot roms, CF card module, or any of that expensive stuff.  

Also to be included with this are tools that natively talk the LLVS protocol so that you can retrieve and store content to your host machine from "standard" CP/M systems.

Obviously this also requires a host/terminal side of things too, which is being implemented in python currently, but could easily be reimplemented in C/C++ to be compiled in with the Pi Zero Serial Terminal module, so that you can use the Pi Zero's SD card as your CP/M storage device.

RC2014 Pro Build

I have most of an RC2014 Pro kit around, and I'd like to build up the various parts of it including the backplane, compact flash storage, and so on, so that I can finally do a native CP/M boot up.  This could be combined with the LLVS above to allow for easy transfers to and from the CP/M system and your "host" system.

I have a few modules that I want to build up and test and experiment with... i've just never really dug in to work on it.


Llichen-80 is a CP/M kernel-based system that takes my LLVS-based system a step further, and adds in the TMS-9918A video card as its main graphics display.  This could be used simultaneously with the standard terminal, or as a replacement to it.  I haven't quite figured all of that out yet.  

I plan on making a few CP/M programs that configure the TMS and download files from the mass storage device into it, for loading fonts, graphics, etc.  Or just to use it for console output.

For use with a single composite display, I also have an hardware video switcher (simply two relays with a digital gpio input) that could be connected to a digital out from the RC2014 or as a GPIO line from the Pi Zero on the Pi Zero Serial Terminal card.

I have some of the basics of this working, but nothing really solidified.

The Llichen-80 system consists of an RC2014 CPU, Clock, Pi Zero Serial Terminal cards, along with the TMS9918A video card.  The Pi Zero Serial card is set up with a PiZero W, and is not running the standard PiGfx kernel, but instead running linux, so that it can run my python terminal application, so that i can add in all of the LLVS code

RC2014 Mini / Micro Mods for CP/M

It's well known that by removing some components on these boards, you can use them as a standard CPU module when upgrading to a CP/M system... replacing the fixed RAM/ROM for the switchable RAM/ROM and so on.  But it would be nice to be able to simplify this so that the RAM/ROM on the RC2014 Mini or RC2014 Micro could be made to be switchable using a simple jumper to connect to the logic needed to do the switching.  Not sure that this even makes sense being that the Mini CP/M upgrade exists, but I'll be thinking about it...

RC2014 Peripheral and IO Switcher Traffic Cop Thing

This one is more of a musing about a new Z80 system architecture, but it could be prototyped using lightly modified  RC2014 modules.

I feel like a peripheral manager type of card might be useful for a new system... one board that has ALL of the logic for peripherals, to switch them on and off, so that peripheral cards needn't have this logic repeated on all of them.  Then it could be vastly simplified for chip count.  It could handle catching bus requests for reading/writing memory or port based io, and work it out to be a single enable/disable line to be run to your peripherals.  That way peripheral cards could be made much simpler, and more easily moved around in the RC2014 memory and IO space... perhaps even live while the system is running.  It would be easy to make it such that any peripheral could be moved to any address, enabled, disabled, etc. Hmm...