Smallest Discrete Transistor 555 Timer

May 11, 2021 by Chris Lott 28 Comments

Over at Tiny Transistor labs, [Robo] took it upon himself to reproduce the classic 555 timer in discrete transistor form. For bonus points, he also managed to put it in a package that’s the same basic size, pin compatible with, and a plug-in replacement for the original. The first task was deciding which 555 circuit to implement. He examined a handful of different implementations — and by examined, we mean dissected them and studied the die circuitry under a microscope. In the end, he went with Hans Camenzind’s original circuit, both as a tribute and because it used the fewest transistors — a point which helped manage the final size, which is only a little bit bigger than the IC!

Speaking of sizes, have you ever soldered an EIA 01005 resistor? We agree with [mbedded.ninja] who wrote on a post about standard chip resistor sizes, the 01005 is a “ridiculously small chip package that can barely be seen by the naked eye.” It is 16 thou x 8 thou (0.4 mm x 0.2 mm) in size, and despite its name and placement in the Imperial series, it is not half the size of an 0201. The transistors are your standard 2N3904 / 2N3906, but purchased in a not-so-standard DFN (Dual Flat Pack, No Leads). We might think a 1.0 x 0.6 mm component as small, but compared to its neighboring resistors in this circuit, it’s huge.

[Robo] has done this kind of project before, most recently making a discrete recreation of of the classic 741 op-amp. We covered a similar, but larger, discrete 555 timer project back in 2011. If you want to go really big-scale with your own reproduction project, check out the MOnSter 6502 from five years ago for further inspiration. Thanks to [Lucas] for the tip.

Digital Preservation For Old Batteries

October 22, 2020 by Tom Nardi 22 Comments

The times they are a-changin’. It used to be that no household was complete without a drawer filled with an assortment of different sizes and types of batteries, but today more and more of our gadgets are using integrated rechargeable cells. Whether or not that’s necessarily an improvement is probably up for debate, but the fact of the matter is that some of these old batteries are becoming harder to find as time goes on.

Which is why [Stephen Arsenault] wants to preserve as many of them as possible. Not in some kind of physical battery museum (though that does sound like the sort of place we’d like to visit), but digitally in the form of 3D models and spec sheets. The idea being that if you find yourself in need of an oddball, say the PRAM battery for a Macintosh SE/30, you could devise your own stand-in with a printed shell.

The rather brilliantly named Battery Backups project currently takes the form of a Thingiverse Group, which allows other alkaline aficionados to submit their own digitized cells. The cells that [Stephen] has modeled so far include not only the STL files for 3D printing, but the CAD source files in several different flavors so you can import them into your tool of choice.

Like the efforts to digitally preserve vintage input devices, it’s not immediately clear how many others out there are willing to spend their afternoons modeling up antiquated batteries. But then again, we’ve long since learned not to underestimate the obscure interests of the hacker community.

Vintage Toys Live On Through 3D Printing

December 24, 2018 by Tom Nardi 5 Comments

We all have fond memories of a toy from our younger days. Most of which are still easy enough to get your hands on thanks to eBay or modern reproductions, but what if your childhood fancies weren’t quite as mainstream? What if some of your fondest memories involved playing with 1960’s educational games which are now so rare that they command hundreds of dollars on the second-hand market?

That’s the situation [Mike Gardi] found himself in recently. Seeing that the educational games which helped put him on a long and rewarding career in software development are now nearly unobtainable, he decided to try his hand at recreating them on his 3D printer. With his keen eye for detail and personal love of these incredible toys, he’s preserved them in digital form for future generations to enjoy.

His replica of “The Amazing Dr. Nim” needed to get scaled-down a bit in order to fit on your average desktop 3D printer bed, but otherwise is a faithful reproduction of the original injection molded plastic computer. The biggest difference is that his smaller version uses 10 mm (3/8 inch) steel ball bearings instead of marbles to actuate the three flip-flops and play the ancient game of Nim.

[Mike] has also created a replica of “Think-a-Dot”, another game which makes use of mechanical flip-flops to change the color of eight dots on the front panel. By dropping marbles in the three holes along the top of the game, the player is able to change the color of the dots to create various patterns. The aim of the game is to find the fewest number of marbles required to recreate specific patterns as detailed in the manual.

Speaking of which, [Mike] has included scans of the manuals for both games, and says he personally took them to a local shop to have them professionally printed and bound as they would have been when the games were originally sold. As such, the experience of owning one of these classic “computer” games has now been fully digitized and is ready to be called into corporeal form on demand.

This is really a fascinating way of preserving physical objects, and we’re interested to see if it catches on with other toys and games which otherwise might be lost to time. As storage capacities get higher and our ability to digitize the world around us improve, we suspect more and more of our physical world will get “backed up” onto the Internet.