Alvaro Prieto makes great use of “After Dark” in this digital clock project:

Reloj: 7400 Series Digital Clock

This project was inspired by my dad’s university digital systems project from the late 1970’s. I found the writeup and schematic and decided to try and re-create it. You can see the results of the breadboard reproduction and explanations in this twitter thread.

After a while, I figured it would be fun to make a soldering kit out of it, which resulted in this.

The design is fairly close to the original, but with the addition of a crystal-backed alternate clock source. The 555 timer cock source works, but drifts like crazy, so if you want to use it as an actual clock, you still can with the alt source.

If you want to take a look at the actual paper, you can see the scanned version here.

Design Files

You can get the latest files in the github releases.

For v1.2, you can use my OSHPark shared project or by grabbing the gerbers from the release.

Assembly Instructions

You can find semi-detailed assembly instructions here.

Tom Fleet writes on Hackster:

Are You Shelling Out Too Much on ATE? Has a Few Tricks to Help You Claw Back Some Margins!

Anyone of us can build something.

Fewer of us, myself included, excel at building a great number of something, and when it comes to scaling a design to any level of volume production, it quickly becomes obvious that in order to save your sanity, the only sensible option is to outsource the onerous process of production to an OEM, or similar set of subcontracted companies, that can handle the production of your products.

Some of them make designing the board seem like the easy bit. You’ll need a clear and concise build pack, not only with the PCB data supplied in the preferred format of your fab house, but also preferably with clear supporting documents to illustrate any quirks of the design that might need explaining.

The BoM must be complete and well sourced, backup suppliers and all. And providing you can get a well assembled set of PCBA out the end of your subcontracted process, you then have the not insignificant task of verifying the work that has been done — you need to test, and program if required — this box of boards that you have been delivered.

The type of testng that you might apply to these boards is going to be dictated by what they do. For something such as a simple SAO, that might mean poking a bit of pin header, attached to a coin cell battery, into the required pins.

For a more complex board, such as the OrangeCrab FPGA development board, things can quickly start to get a bit more involved… There is a whole suite of functionality to validate — from the basics of bringing up the power supplies,to ascertaining the analog inputs, and finally booting a bit-stream, there’s a fair amount of functionality that needs that “final test” check mark.

ToorCamp 2020 was originally scheduled for June 23rd-28th, 2020 but due to the COVID-19 Pandemic, it’s been postponed until July 14-18th 2021. Instead, we’ve decided to host VirtualToor the weekend of June 27-28th as a self-organized event with talks, village hangouts, contests, and project collaborations to help ToorCampers build up momentum on research and projects for the event next year.

If you have ideas for talks, projects, contests, or other virtual events, please go ahead and post to this wiki. We’ll follow up if there’s any conflicts or issues with the self-organized content.

Find out more!