schematics

15 Articles

Apollo-era PCB Reverse Engineering To KiCad

November 25, 2024 by 24 Comments

Earlier this year [Skyhawkson] got ahold of an Apollo-era printed circuit board which he believes was used in a NASA test stand. He took high quality photos of both sides of the board and superimposed them atop each other. After digging into a few obsolete parts from the 1960s, he was able to trace out the connections. I ran across the project just after making schematics for the Supercon badge and petal matrix. Being on a roll, I decided to take [Skyhawkson]’s work as a starting point and create KiCad schematics. Hopefully we can figure out what this circuit board does along the way.

The board is pretty simple:

  • approximately 6.5 x 4.5 inches
  • 22 circuit edge connector 0.156 in pitch
  • 31 ea two-terminal parts ( resistors, diodes )
  • 3 ea trimmer potentiometers
  • 7 ea transistors
  • parts arranged in 4 columns

Continue reading “Apollo-era PCB Reverse Engineering To KiCad” →

Supercon 2024 SAO Petal KiCad Redrawing Project

November 19, 2024 by 4 Comments

Last week I completed the SAO flower badge redrawing task, making a complete KiCad project. Most of the SAO petals are already released as KiCad projects, except for the Petal Matrix. The design features 56 LEDs arranged in eight spiral arms radiating from the center. What it does not feature are straight lines, right angles, nor parts placed on a regular grid.

Importing into KiCad

Circuit Notes for LEDs, Thanks to [spereinabox]
I followed the same procedures as the main flower badge with no major hiccups. This design didn’t have any released schematics, but backing out the circuits was straightforward. It also helped that user [sphereinabox] over on the Hackaday Discord server had rung out the LED matrix connections and gave me his notes.

Grep Those Positons

I first wanted to only read the data from the LEDs for analysis, and I didn’t need the full Kicad + Python scripting for that. Using grep on the PCB file, you get a text file that can be easily parsed to get the numbers. I confirmed that the LED placements were truly as irregular as they looked.

My biggest worry was how obtain and re-apply the positions and angles of the LEDs, given the irregular layout of the spiral arms. Just like the random angles of six SAO connector on the badge board, [Voja] doesn’t disappoint on this board, either. I fired up Python and used Matplotlib to get a visual perspective of the randomness of the placements, as one does. Due to the overall shape of the arms, there is a general trend to the numbers. But no obvious equation is discernable.

Continue reading “Supercon 2024 SAO Petal KiCad Redrawing Project” →

Supercon 2024 Flower SAO Badge Redrawing In KiCad

October 31, 2024 by 12 Comments

Out of curiosity, I redrew the Supercon Vectorscope badge schematics in KiCad last year. As you might suspect, going from PCB to schematic is opposite to the normal design flow of KiCad and most other PCB design tools. As a result, the schematics and PCB of the Vectorscope project were not really linked. I decided to try it again this year, but with the added goal of making a complete KiCad project. As usual, [Voja] provided a well drawn schematic diagram in PDF and CorelDRAW formats, and a PCB design using Altium’s Circuit Maker format (CSPcbDoc file). And for reference, this year I’m using KiCad v8 versus v7 last year.

Importing into KiCad

This went smoothly. KiCad imports Altium files, as I discovered last year. Converting the graphic lines to traces was easier than before, since the graphical lines are deleted in the conversion process. There was a file organizational quirk, however. I made a new, empty project and imported the Circuit Maker PCB file. It wasn’t obvious at first, but the importing action didn’t make use the new project I had just made. Instead, it created a completely new project in the directory holding the imported Circuit Maker file. This caused a lot of head scratching when I was editing the symbol and footprint library table files, and couldn’t figure out why my edits weren’t being seen by KiCad.  I’m not sure what the logic of this is, was an easy fix once you know what’s going on. I simply copied everything from the imported project and pasted it in my new, empty project. Continue reading “Supercon 2024 Flower SAO Badge Redrawing In KiCad” →

Hack All The Things, Get All The Schematics

July 8, 2024 by 32 Comments

When I was growing up, about 4 or 5 years old, I had an unorthodox favourite type of reading material: service manuals for my dad’s audio equipment. This got to the point that I kept asking my parents for more service manuals, and it became a running joke in our family for a bit. Since then, I’ve spent time repairing tech and laptops in particular as a way of earning money, hanging out at a flea market in the tech section, then spending tons of time at our hackerspace. Nowadays, I’m active in online hacker groups, and I have built series of projects closely interlinked with modern-day consumer-facing tech.

Twenty three years later, is it a wonder I have a soft spot in my heart for schematics? You might not realize this if you’re only upcoming in the hardware hacking scene, but device schematics, whichever way you get them, are a goldmine of information you can use to supercharge your projects, whether you’re hacking on the schematic-ed device itself or not. What’s funny is, not every company wants their schematics to be published, but it’s ultimately helpful for the company in question, anyway.

If you think it’s just about repair – it’s that, sure, but there’s also a number of other things you might’ve never imagined you can do. Still, repair is the most popular one.
Continue reading “Hack All The Things, Get All The Schematics” →

Schematics, For A Modern Flagship Phone

February 7, 2024 by 36 Comments

The mobile phone is an expensive and often surprisingly fragile device, whose manufacturers are notorious for making them as difficult to repair as possible. Glued-together cases and unreplaceable batteries abound, and technical information is non-existent. But amongst all that there’s one manufacturer with a different approach — Fairphone. Case in point, they’ve released the full service guide including schematics for their flagship Fairphone 5.

Fairphone’s selling point is the repairability and internal accessibility of their products and of course they’ve made hay with this as a marketing opportunity. But aside from that, it’s a fascinating chance to look in-depth at a modern smartphone from the inside out. We see the next-level PCB layout and how everything is so neatly packed into the minimum space, all without resorting to a heat gun.

It’s great to have another hackable phone, and fair play to Fairphone for releasing all this stuff, but perhaps the most interesting part from where we’re sitting is how and where this phone is being sold. There have been hackable phones before, for many the Pinephone will spring to mind, but they have always been sold to an audience who buy to hack. Here in Europe where this is being written, the Fairphone is being sold as a consumer device. It won’t shake Apple or Samsung from their perches, but for a hackable device to be so generally available to those who wish to do things with it can never be a bad thing.

We took a quick look at Fairphone back in 2015, when they launched.

Vectorscope KiCad Redrawing Project

November 13, 2023 by 23 Comments

When I saw this year’s Supercon Vectorscope badge, I decided that I had to build one for myself. Since I couldn’t attend in-person, I immediately got the PCBs and parts on order. Noting that the GitHub repository only had the KiCad PCB file and not the associated schematics and project file, I assumed this was because everyone was in a rush during the days leading up to Supercon weekend. I later learned, however, that there really wasn’t a KiCad project — the original design was done in Circuit Maker and the PCB was converted into KiCad. I thought, “how hard can this be?” and decided to try my hand at completing the KiCad project.

Fortunately I didn’t have to start from scratch. The PCB schematics were provided, although only as image files. They are nicely laid out and fortunately don’t suffer the scourge of many schematics these days — “visual net lists” that are neither good schematics nor useful net lists. To the contrary, these schematics, while having a slightly unorthodox top to bottom flow, are an example of good schematic design. Continue reading “Vectorscope KiCad Redrawing Project” →

Pocket Radio Powered By Tiny Microcontroller

July 6, 2022 by 33 Comments

Before the days of MP3 players and smartphones, and even before portable CD players, those of us of a certain age remember that our cassette players were about the only way to take music on-the-go. If we were lucky, they also had a built-in radio for when the single tape exhausted both of its sides. Compared to then, it’s much easier to build a portable radio even though cassettes are largely forgotten, as [wagiminator] shows us with this radio design based on an ATtiny.

The build is about as compact as possible, with the aforementioned ATtiny 402/412 as its core, it also makes use of an integrated circuit FM tuner,  an integrated audio amplifier with its own single speaker, and a small OLED display. The unit also boasts its own lithium-polymer battery charger and its user interface consists of only three buttons, plenty for browsing radio stations and controlling volume.

The entire build fits easily in the palm of a hand and is quite capable for a mobile radio, plus all of the schematics and code is available on the project page. While it doesn’t include AM capability, just the fact that FM is this accessible nowadays when a few decades ago it was cutting-edge technology is quite remarkable. If you’re looking for an even smaller FM receiver without some of the bells and whistles of this one, take a look at this project too.