John Calhoun
@engineersneedart.com
Old Macintosh shareware author. Making things I wish existed when I was a kid.
engineersneedart.com
github.com/EngineersNeedArt
engineersneedart.com
github.com/EngineersNeedArt
I look back at the 3D-printing that I did in 2025, what I learned:
engineersneedart.com/blog/3dprint...
engineersneedart.com/blog/3dprint...
January 17, 2026 at 10:47 PM
I look back at the 3D-printing that I did in 2025, what I learned:
engineersneedart.com/blog/3dprint...
engineersneedart.com/blog/3dprint...
A power module for a breadboard analog computer. On left: prototype board, on right: 1st iteration from JLCPCB.
December 16, 2025 at 6:49 PM
A power module for a breadboard analog computer. On left: prototype board, on right: 1st iteration from JLCPCB.
Analog computer project in progress. Breadboard first. Circuits that are okay move to prototype boards…
Parts get harvested along the way. IC's are easy because they are socketed. (I can't be bothered to harvest sockets). Switches, large caps… (I have a bunch of crap resistors I'm happy to lose.)
Parts get harvested along the way. IC's are easy because they are socketed. (I can't be bothered to harvest sockets). Switches, large caps… (I have a bunch of crap resistors I'm happy to lose.)
December 11, 2025 at 11:47 PM
Analog computer project in progress. Breadboard first. Circuits that are okay move to prototype boards…
Parts get harvested along the way. IC's are easy because they are socketed. (I can't be bothered to harvest sockets). Switches, large caps… (I have a bunch of crap resistors I'm happy to lose.)
Parts get harvested along the way. IC's are easy because they are socketed. (I can't be bothered to harvest sockets). Switches, large caps… (I have a bunch of crap resistors I'm happy to lose.)
Still prototyping analog computing modules. Moving stuff from breadboard to prototyping boards ("ElectroCookies"). (Red & blue "cookie" seen here.)
An article from a 1970's hobbyist electronics magazine inspired the project. I've gone past that circuit now though. (Unsure where I'll land…)
An article from a 1970's hobbyist electronics magazine inspired the project. I've gone past that circuit now though. (Unsure where I'll land…)
December 4, 2025 at 12:22 PM
Still prototyping analog computing modules. Moving stuff from breadboard to prototyping boards ("ElectroCookies"). (Red & blue "cookie" seen here.)
An article from a 1970's hobbyist electronics magazine inspired the project. I've gone past that circuit now though. (Unsure where I'll land…)
An article from a 1970's hobbyist electronics magazine inspired the project. I've gone past that circuit now though. (Unsure where I'll land…)
Playing with analog computing (but digital metering, so sue me).
Last night (after several hours of hair pulling) I learned that a 1% 10 kΩ resistor color bands is indistinguishable from a 1% 120Ω resistor—that is flipped around.
Breadboarding is messy. Will make up a PCB for part of it soon.
Last night (after several hours of hair pulling) I learned that a 1% 10 kΩ resistor color bands is indistinguishable from a 1% 120Ω resistor—that is flipped around.
Breadboarding is messy. Will make up a PCB for part of it soon.
November 26, 2025 at 2:35 PM
Playing with analog computing (but digital metering, so sue me).
Last night (after several hours of hair pulling) I learned that a 1% 10 kΩ resistor color bands is indistinguishable from a 1% 120Ω resistor—that is flipped around.
Breadboarding is messy. Will make up a PCB for part of it soon.
Last night (after several hours of hair pulling) I learned that a 1% 10 kΩ resistor color bands is indistinguishable from a 1% 120Ω resistor—that is flipped around.
Breadboarding is messy. Will make up a PCB for part of it soon.
A second analog (integrator) channel breadboarded (top). Both channels are tapped and displayed on the ESP32 "software meter" in the center (showing two needles at once).
The new channel uses dual op-amps instead of singles. I may make another analog channel and have a go with a quad op-amp.
The new channel uses dual op-amps instead of singles. I may make another analog channel and have a go with a quad op-amp.
November 11, 2025 at 11:10 PM
A second analog (integrator) channel breadboarded (top). Both channels are tapped and displayed on the ESP32 "software meter" in the center (showing two needles at once).
The new channel uses dual op-amps instead of singles. I may make another analog channel and have a go with a quad op-amp.
The new channel uses dual op-amps instead of singles. I may make another analog channel and have a go with a quad op-amp.
From breadboard (left—wires can be bumped loose) to protoboard (right—wires soldered).
One channel of an analog/digital hybrid computer experiment.
An op-amp acts as an analog-computer integrator, 3 more op-amps scale, offset & invert the voltage so it is within 0.0-3.3V range for the ESP32 ADCs.
One channel of an analog/digital hybrid computer experiment.
An op-amp acts as an analog-computer integrator, 3 more op-amps scale, offset & invert the voltage so it is within 0.0-3.3V range for the ESP32 ADCs.
November 10, 2025 at 11:16 PM
From breadboard (left—wires can be bumped loose) to protoboard (right—wires soldered).
One channel of an analog/digital hybrid computer experiment.
An op-amp acts as an analog-computer integrator, 3 more op-amps scale, offset & invert the voltage so it is within 0.0-3.3V range for the ESP32 ADCs.
One channel of an analog/digital hybrid computer experiment.
An op-amp acts as an analog-computer integrator, 3 more op-amps scale, offset & invert the voltage so it is within 0.0-3.3V range for the ESP32 ADCs.
Each year the wife hand-carves a multi-color X-mas card. A destructive process: inking/printing a color before carving for the next color.
This year I suggested she make just one print at each stage (in black ink) for me to scan digitally—print on the Risograph.
Seems to be going well.
This year I suggested she make just one print at each stage (in black ink) for me to scan digitally—print on the Risograph.
Seems to be going well.
November 10, 2025 at 3:38 PM
Each year the wife hand-carves a multi-color X-mas card. A destructive process: inking/printing a color before carving for the next color.
This year I suggested she make just one print at each stage (in black ink) for me to scan digitally—print on the Risograph.
Seems to be going well.
This year I suggested she make just one print at each stage (in black ink) for me to scan digitally—print on the Risograph.
Seems to be going well.
Mac Plus. I still have it (and it functions—needed recapping and reflowing the solder on the main connector on the mobo).
November 2, 2025 at 1:28 PM
Mac Plus. I still have it (and it functions—needed recapping and reflowing the solder on the main connector on the mobo).
Just having some fun at Pioneer's expense, I guess.
#SpacetoberChallenge #sciart #spaceart #illustration
#SpacetoberChallenge #sciart #spaceart #illustration
October 26, 2025 at 3:14 AM
Just having some fun at Pioneer's expense, I guess.
#SpacetoberChallenge #sciart #spaceart #illustration
#SpacetoberChallenge #sciart #spaceart #illustration
Sweep meter is better. (Here it is responding to potentiometer acting as a voltage divider.)
October 23, 2025 at 5:23 PM
Sweep meter is better. (Here it is responding to potentiometer acting as a voltage divider.)
Working on an "analog" voltage meter for a project. (This slide-rule version will not make the cut.)
October 23, 2025 at 2:07 PM
Working on an "analog" voltage meter for a project. (This slide-rule version will not make the cut.)
After all this iteration, I placed an order for (I hope) the final board. Finishing up the instruction manual as well. I should have the boards for sale on Tindie in November. They're a kind of "breadboard helper" for playing with (learning about) transistor logic circuits.
October 18, 2025 at 3:04 PM
After all this iteration, I placed an order for (I hope) the final board. Finishing up the instruction manual as well. I should have the boards for sale on Tindie in November. They're a kind of "breadboard helper" for playing with (learning about) transistor logic circuits.
Prototyping my first learning-electronics project kit is winding down (I am finishing up the manual as well). Top is through-hole, bottom my first go at surface-mount (I learned a few things and have changed it some).
(Hard to find a domain name these days. Went with CircuitPixies.)
(Hard to find a domain name these days. Went with CircuitPixies.)
October 2, 2025 at 2:07 PM
Prototyping my first learning-electronics project kit is winding down (I am finishing up the manual as well). Top is through-hole, bottom my first go at surface-mount (I learned a few things and have changed it some).
(Hard to find a domain name these days. Went with CircuitPixies.)
(Hard to find a domain name these days. Went with CircuitPixies.)
Getting a "Buc-ee's" vibe from Wallys.
I started a project to create modern road trip place-mats. Here is I-80 across Iowa:
I started a project to create modern road trip place-mats. Here is I-80 across Iowa:
September 29, 2025 at 2:37 PM
Getting a "Buc-ee's" vibe from Wallys.
I started a project to create modern road trip place-mats. Here is I-80 across Iowa:
I started a project to create modern road trip place-mats. Here is I-80 across Iowa:
September 20, 2025 at 12:35 AM
My oldest daughter and I each have refurb'ed Riso machines. But she has a blue ink drum and I do not. With her visiting for a few days, she brought her drums and I was able to test a few Riso ideas out.
#riso
#risograph
#riso
#risograph
September 17, 2025 at 5:35 PM
My oldest daughter and I each have refurb'ed Riso machines. But she has a blue ink drum and I do not. With her visiting for a few days, she brought her drums and I was able to test a few Riso ideas out.
#riso
#risograph
#riso
#risograph
Thanks, @ronscompvids.bsky.social for your midwest hospitality at #vcfmw this year. (And so many Mac laptops!) See you next year.
September 15, 2025 at 2:54 AM
Thanks, @ronscompvids.bsky.social for your midwest hospitality at #vcfmw this year. (And so many Mac laptops!) See you next year.
The process of prototyping an electronic project/PCB (from top to bottom). (I'm finishing up the project book now.)
September 7, 2025 at 9:45 PM
The process of prototyping an electronic project/PCB (from top to bottom). (I'm finishing up the project book now.)
So a guy (Daniel Valcanover) has spent 25 years trying to find a boxed version of the original Glider for Windows has tracked one down.
Apparently he'll post the binary on MobyGames soon. Maybe here: www.mobygames.com/game/3998/gl...
Even a photo of the box was unobtainium — until now of course.
Apparently he'll post the binary on MobyGames soon. Maybe here: www.mobygames.com/game/3998/gl...
Even a photo of the box was unobtainium — until now of course.
June 4, 2025 at 6:14 PM
So a guy (Daniel Valcanover) has spent 25 years trying to find a boxed version of the original Glider for Windows has tracked one down.
Apparently he'll post the binary on MobyGames soon. Maybe here: www.mobygames.com/game/3998/gl...
Even a photo of the box was unobtainium — until now of course.
Apparently he'll post the binary on MobyGames soon. Maybe here: www.mobygames.com/game/3998/gl...
Even a photo of the box was unobtainium — until now of course.
I'm not sure I ever received the floppy disk, but I have the box and manual for the (rare?) Japanese version of Glider 4.0.
Maybe someone can track down the binary.
#VintageMac #RetroGaming
Maybe someone can track down the binary.
#VintageMac #RetroGaming
May 18, 2025 at 3:00 AM
I'm not sure I ever received the floppy disk, but I have the box and manual for the (rare?) Japanese version of Glider 4.0.
Maybe someone can track down the binary.
#VintageMac #RetroGaming
Maybe someone can track down the binary.
#VintageMac #RetroGaming