The Hotel Chaos: Spaghetti Hardware! - Page 1
Forum section: electronics / projects

author: richmit
author_rank: Contributor
timestamp: September 12, 2021, 08:49:38 pm
content: It happened the same way spaghetti code usually happens. I started without a plan, and repeatedly added random bits to the thing. Eventually, and it felt quite sudden, the comedic absurdity of it all became overwhelming.It's embarrassing to have constructed this thing. Still, it cracks me up just looking at it, so I figured I would share.It started innocently enough a year ago. I breadboarded the Lorenz strange attractor circuit from "The Art of Electronics". Then I wanted to spin it around, so I got a sin/cos potentiometer on EBay and breadboarded an analog rotation matrix multiplier. Then I wanted to shift the z-axis down, so I breadboarded a shifter. Then I thought, it would be cool to make the rotation angle programmable so the thing would spin under MCU control. I had no breadboard space left! So I moved the rotation circuit to a bit of perfboard. I wired up a an MSP430 EVM, a LCD, a DAC module, and a button module. Nice. Then I added a perfboard with a second rotation matrix. Things were getting messy, so I bolted the perfboards together. Then I added three perfboards with shift & scale circuits -- one for each axis. Then I had such a mess of wires on the bench I couldn't find the button module connected to the MCU, so I attached the buttons and display to another perfboard. Then I added an encoder. Then I thought it would be cool if the scale and shift could be programmable too, so I got a 16 channel DAC and attached it to a bit perfboard, built a new shift & scale perfboard, and put the old ones in a drawer. Then I added another rotation board. Then I decided to mount the remaining bits to yet another bit of perfboard, and bolt it all together... Funny thing is, I'm thinking of adding another board to add a perspective transformation...My wife says it looks like a hotel, so I have named this monstrosity "The Hotel Chaos".I posted the following result from an earlier version of this hardware in the The Rössler attractor challenge thread:At the time it only did rotations -- note the programmed sequence of rotations. In theory, now that I have programmable scale, shift, & rotation I could program flight simulator-like flyovers for strange attractors on my analog scope.

author: rstofer
author_rank: Super Contributor
timestamp: September 12, 2021, 11:47:39 pm
content: That's a magnificent project! Great work!

author: gnavigator1007
author_rank: Unknown
timestamp: September 13, 2021, 01:11:10 am
content: I mean this in the most complimentary way, it looks to me like something the doozers from Fraggle Rock would build if the Jim Henson company ever made an episode where they travel to the future. Nice work

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: September 13, 2021, 01:46:37 am
content: It has got to be hella-annoying trying to read that display and operate that rotary encoder whilst spinning. I like it.

author: gcewing
author_rank: Regular Contributor
timestamp: September 13, 2021, 09:47:23 am
content: Welcome to the Hotel Chaos! You can switch off any time you like, but you can never leave...

author: Old Printer
author_rank: Frequent Contributor
timestamp: September 13, 2021, 12:35:14 pm
content: The question begs.... did you ever have to troubleshoot it?

author: richmit
author_rank: Contributor
timestamp: September 13, 2021, 03:10:29 pm
content: Quote from: Old Printer on September 13, 2021, 12:35:14 pmOh, yes! On the plus side, I'm never in want for a place to attach a scope probe!Seriously. It's three analog signal processing pipelines with discrete steps -- so you know what the signal should look like between each of the steps. Debugging is mostly just checking the signal along the path (i.e. between the boards) till you find the place something looks wonky.