Christopher Mitchell
@kermmartian.z80.me
Director of Geospatial AI @nbcuniversal.com, CS Ph.D., founder @Cemetech, hardware and software hacker, distributed systems guru, lover of trains. Opinions are my own.
I think it's that time again.
November 10, 2025 at 2:21 AM
I think it's that time again.
August 31, 2025 at 3:24 PM
A Tail of Two Kitties.
August 8, 2025 at 1:58 PM
A Tail of Two Kitties.
A very accurate summary of my day today. #GreatestGathering #SoManyTrains
August 2, 2025 at 11:12 PM
A very accurate summary of my day today. #GreatestGathering #SoManyTrains
It may just be cardboard, but physical prototyping of my Class 80x train simulator at 1:1 scale has been very helpful in figuring out if I've gotten the size and layout right, not to mention reasonable for my desk: z80.me/blog/tsc-das...
August 1, 2025 at 9:33 AM
It may just be cardboard, but physical prototyping of my Class 80x train simulator at 1:1 scale has been very helpful in figuring out if I've gotten the size and layout right, not to mention reasonable for my desk: z80.me/blog/tsc-das...
In another project completed recently, I added UK-style horn controls to my burgeoning train simulator. 🔊 Thanks to my reusable CAN bus controller, it took an afternoon, mostly of soldering and crimping: z80.me/blog/tsc-hor...
June 22, 2025 at 3:51 PM
In another project completed recently, I added UK-style horn controls to my burgeoning train simulator. 🔊 Thanks to my reusable CAN bus controller, it took an afternoon, mostly of soldering and crimping: z80.me/blog/tsc-hor...
I've been writing 3D graphing programs for assorted graphing calculators since at least 2003. Now, after starting a 3D grapher for the TI-84 Plus CE and then pausing for eight years (coincidentally roughly the time since @geopipe.ai was founded), I've released it: www.cemetech.net/forum/viewto...
June 21, 2025 at 2:09 PM
I've been writing 3D graphing programs for assorted graphing calculators since at least 2003. Now, after starting a 3D grapher for the TI-84 Plus CE and then pausing for eight years (coincidentally roughly the time since @geopipe.ai was founded), I've released it: www.cemetech.net/forum/viewto...
Achievement unlocked: realized I've actually been to today's Worldle, quite a few years ago for an academic conference.
May 15, 2025 at 1:09 AM
Achievement unlocked: realized I've actually been to today's Worldle, quite a few years ago for an academic conference.
I'm loving it so far. It's great for one of the main reasons I wanted it, a nearly-life-sized train simulator "windscreen". Also good for media, and with Windows' PowerToys, reasonably good for spreading ~five applications across, like my old five-monitor setup.
March 18, 2025 at 7:25 PM
I'm loving it so far. It's great for one of the main reasons I wanted it, a nearly-life-sized train simulator "windscreen". Also good for media, and with Windows' PowerToys, reasonably good for spreading ~five applications across, like my old five-monitor setup.
What do you do when you want to build a train dashboard, but you don't have a train to measure? You figure out how to parse an obscure 3D model format, derive the planes the buttons lie in, and build a papercraft prototype. z80.me/blog/tsc-das...
February 1, 2025 at 3:07 PM
What do you do when you want to build a train dashboard, but you don't have a train to measure? You figure out how to parse an obscure 3D model format, derive the planes the buttons lie in, and build a papercraft prototype. z80.me/blog/tsc-das...
Okay, that works, and the RS-422 interface spits out...something. Now how do I talk to you?
January 27, 2025 at 5:47 PM
Okay, that works, and the RS-422 interface spits out...something. Now how do I talk to you?
Am I taking crazy pills?
January 9, 2025 at 3:34 PM
Am I taking crazy pills?
No thank you, we don't do that here.
January 1, 2025 at 1:42 AM
No thank you, we don't do that here.
Caturday: the more shy of our two void kittens briefly being social (on a graphing calculator pillow).
December 29, 2024 at 2:11 AM
Caturday: the more shy of our two void kittens briefly being social (on a graphing calculator pillow).
My new monitor has arrived...
December 12, 2024 at 3:37 PM
My new monitor has arrived...
Including my Graph3DC! Great job to the programmers and hackers of the graphing calculator community for another productive month.
November 27, 2024 at 8:22 PM
Including my Graph3DC! Great job to the programmers and hackers of the graphing calculator community for another productive month.
Thanks to the DC chapter of the National Railroad Historical Society, I enjoyed an in-depth tour of Amtrak's Ivy City maintenance facility. I was particularly struck by the pride the folks there expressed in the quality and speed of their work and its importance in keeping the railroad running.
November 18, 2024 at 5:31 PM
Thanks to the DC chapter of the National Railroad Historical Society, I enjoyed an in-depth tour of Amtrak's Ivy City maintenance facility. I was particularly struck by the pride the folks there expressed in the quality and speed of their work and its importance in keeping the railroad running.
The rest of the world to the US, probably.
November 5, 2024 at 1:43 PM
The rest of the world to the US, probably.
I'm porting a 3D graphing program I wrote for another platform to the ez80 TI-84 Plus CE; among today's progress was switching graph color themes to palette-swapping. Recalculating per-point RGB values and converting to RGB332 is now an instant change.
October 25, 2024 at 4:37 AM
I'm porting a 3D graphing program I wrote for another platform to the ez80 TI-84 Plus CE; among today's progress was switching graph color themes to palette-swapping. Recalculating per-point RGB values and converting to RGB332 is now an instant change.
Metro North kindly opened up their Croton Harmon facility for a great open house yesterday, a previously annual event of which I have fond childhood memories. #trains #metronorth
October 6, 2024 at 2:44 PM
Metro North kindly opened up their Croton Harmon facility for a great open house yesterday, a previously annual event of which I have fond childhood memories. #trains #metronorth
Today in rare #calculators that have joined my collection: a TI-Nspire CAS+ prototype, similar to the TI-Nspire CAS that was released in 2007. I'm glad they reworked the center "joystick". www.datamath.org/Graphing/NSp...
August 29, 2024 at 7:22 PM
Today in rare #calculators that have joined my collection: a TI-Nspire CAS+ prototype, similar to the TI-Nspire CAS that was released in 2007. I'm glad they reworked the center "joystick". www.datamath.org/Graphing/NSp...