Mark J. Koch
@markjkoch.bsky.social
Retired Digital Alchemist. Cyber Monk. Technologist. Containment Specialist at -redacted-. Sun Microsystems Labs Alumni. Former SFX specialist at Blue Man Group. Hobbies: Game Design in Java/JavaFX, Analog Synth, PCB design, Robots, Gardening, Cooking.
A nice way to end the week! Got my #synth module working. Based on an open source design by Hagiwo. #RasPi #Pico2 based and using Arduino libraries, generates waves from tables or math. I added OLED and UI code. I think the PCB components need work as the output looks a little funky. #asmr-synth
October 4, 2025 at 1:20 AM
A nice way to end the week! Got my #synth module working. Based on an open source design by Hagiwo. #RasPi #Pico2 based and using Arduino libraries, generates waves from tables or math. I added OLED and UI code. I think the PCB components need work as the output looks a little funky. #asmr-synth
#synth rack progress! One regulator wouldn't start up, so it took a deeper read into the data sheet to realize I'd missed some components needed for voltages above 5V (a zener and cap). #Zener ended up being a stack of Zeners to achieve desired value. Not my prettiest fix. #pcb #kicad #electronics
September 27, 2025 at 10:17 PM
#synth rack progress! One regulator wouldn't start up, so it took a deeper read into the data sheet to realize I'd missed some components needed for voltages above 5V (a zener and cap). #Zener ended up being a stack of Zeners to achieve desired value. Not my prettiest fix. #pcb #kicad #electronics
I don’t have a #Mouser parts purchasing problem! I can stop any time I want. #kicad #pcb #engineering
September 24, 2025 at 3:05 AM
I don’t have a #Mouser parts purchasing problem! I can stop any time I want. #kicad #pcb #engineering
My #JLCPCB bounty included my prototype #PCB s for a new type of rack #synth that I am thinking about. Think #eurorack but dragged into the new millennium. Backplane has two #I2C busses, slot detection, and 32 negotiated patch signals. Slightly larger such that old ER modules can nest inside.
September 16, 2025 at 8:11 PM
Yay! The main #PCB for my MOS #KIM-1 replica arrived today from #JLCPCB! The sub-boards seem to fit. Bringup will take awhile since there's a gross chip-pin-numbering error on one of the smaller boards and I'll have to re-fab it. But I'll be able to partially assemble it and test a few things.
September 16, 2025 at 7:51 PM
When your latest #PCB uses a #PCI connector (super dirt cheap) and you want the customer to know that they should not even be tempted to plug it into a PC. I used the connector but the pinout and voltages are nowhere near those of PC Cards. At least the warning will be entertaining. #KiCAD
September 8, 2025 at 4:38 AM
It's alive! Keypad/Display #PCB module for my #kim-1 replica is working! Mostly based on the original 1970s #schematic, using modern parts. I wrote a PCB test fixture using Arduino and #rp2040 #raspberrypipico module from #adafruit. My first time using a rp2040 was mostly painless. #65C02
August 28, 2025 at 9:20 PM
It's alive! Keypad/Display #PCB module for my #kim-1 replica is working! Mostly based on the original 1970s #schematic, using modern parts. I wrote a PCB test fixture using Arduino and #rp2040 #raspberrypipico module from #adafruit. My first time using a rp2040 was mostly painless. #65C02
Tracking the person delivering my #UPS package. This individual should get a job in professional gerrymandering. Has driven past my neighborhood twice already and returned to multiple places they were before. Package is also an hour after the original delivery window. This is performance art.
August 25, 2025 at 11:51 PM
Tracking the person delivering my #UPS package. This individual should get a job in professional gerrymandering. Has driven past my neighborhood twice already and returned to multiple places they were before. Package is also an hour after the original delivery window. This is performance art.
When a billionaire/celebrity/philanthropist looks at your profile on LinkedIn and you’re not sure if you should be elated or worried.
August 24, 2025 at 1:21 AM
When a billionaire/celebrity/philanthropist looks at your profile on LinkedIn and you’re not sure if you should be elated or worried.
My #analytical brain, every time I touch something and get a #shock: "I've been sitting still for five minutes! Why am I loosing so many #electrons so quickly? Is there something I can do about it?" #zap
August 18, 2025 at 6:34 PM
My #analytical brain, every time I touch something and get a #shock: "I've been sitting still for five minutes! Why am I loosing so many #electrons so quickly? Is there something I can do about it?" #zap
This is a public service announcement for you to support your local PBS station! #PBS #RickSteves
August 15, 2025 at 4:04 PM
This is a public service announcement for you to support your local PBS station! #PBS #RickSteves
My @oshpark.bsky.social PCBs arrived. They are part of my #kicad project to create a #KIM-1 #65c02 computer replica, with a twist. I started with the original schematic but broke it into SMT modules. Each module is a castellated #PCB "stamp" for a larger main board that I'm finishing up.
August 9, 2025 at 9:14 PM
My @oshpark.bsky.social PCBs arrived. They are part of my #kicad project to create a #KIM-1 #65c02 computer replica, with a twist. I started with the original schematic but broke it into SMT modules. Each module is a castellated #PCB "stamp" for a larger main board that I'm finishing up.
If they ever reboot "Back to the Future", they should use the #CyberTruck. Except, on this new set of movies, to activate time travel, you'd have to rear-end the CyberTruck using a different vehicle at 88MPH. It would help add one more metaphor to the "Back" part of the name in the title.
July 22, 2025 at 8:42 PM
If they ever reboot "Back to the Future", they should use the #CyberTruck. Except, on this new set of movies, to activate time travel, you'd have to rear-end the CyberTruck using a different vehicle at 88MPH. It would help add one more metaphor to the "Back" part of the name in the title.
Me repeatedly asking my partner if they want to go to Sushi: "I don't know. Maybe next week."
Me asking my partner once about attending a ham radio meetup: "Yes! Let's go!"
Someday little nigiri, some day soon.
Me asking my partner once about attending a ham radio meetup: "Yes! Let's go!"
Someday little nigiri, some day soon.
June 26, 2025 at 7:46 PM
Me repeatedly asking my partner if they want to go to Sushi: "I don't know. Maybe next week."
Me asking my partner once about attending a ham radio meetup: "Yes! Let's go!"
Someday little nigiri, some day soon.
Me asking my partner once about attending a ham radio meetup: "Yes! Let's go!"
Someday little nigiri, some day soon.
I am so screwed…
Never trust anyone online whose icon appears to be a photograph of a human being.
June 24, 2025 at 11:08 PM
I am so screwed…
Ughhh! That 2 degree twist on the audio jack. Thanks #kicad! And thus I kick off the official open source version of my custom "tuned" KiCAD library. I can't be that harsh since #EagleCAD included libraries were full of this kind of anomalous shenanigans that gave me trust issues. #PCB
June 24, 2025 at 10:30 PM
Reposted by Mark J. Koch
Engineers have opinions about coordinate spaces.
June 5, 2025 at 10:12 PM
Engineers have opinions about coordinate spaces.
Managed to finish this #STEAM project today. "Matrix Flowers 1", based on cheap #LED segment modules from #Amazon with an added custom @oshpark.bsky.social PCB using a #ATmega328p
GitHub: github.com/CircuitMonke... #electronics #flowers #LEDs #arduino #microcontroller
youtu.be/2mtg5pHPPw4?...
GitHub: github.com/CircuitMonke... #electronics #flowers #LEDs #arduino #microcontroller
youtu.be/2mtg5pHPPw4?...
Matrix Flowers 1
YouTube video by Mark Koch
youtu.be
May 16, 2025 at 12:24 AM
Managed to finish this #STEAM project today. "Matrix Flowers 1", based on cheap #LED segment modules from #Amazon with an added custom @oshpark.bsky.social PCB using a #ATmega328p
GitHub: github.com/CircuitMonke... #electronics #flowers #LEDs #arduino #microcontroller
youtu.be/2mtg5pHPPw4?...
GitHub: github.com/CircuitMonke... #electronics #flowers #LEDs #arduino #microcontroller
youtu.be/2mtg5pHPPw4?...
Reposted by Mark J. Koch
May 10, 2025 at 1:46 AM
Wrapping up my week by getting some good results from my current project. I got a #Adafruit Qualia #ESP32 dev board which is made for interfacing to the newer IPS LCD displays. It has a touch screen as well! Had to crash learn some #CircuitPython and was able to code a working GUI Widget set.
May 9, 2025 at 5:49 PM
Wrapping up my week by getting some good results from my current project. I got a #Adafruit Qualia #ESP32 dev board which is made for interfacing to the newer IPS LCD displays. It has a touch screen as well! Had to crash learn some #CircuitPython and was able to code a working GUI Widget set.