This past week we introduced our “Three Fives” discrete 555 timer kit, which comes with a set of “legs” to make it look like a (DIP packaged) integrated circuit. In that introduction, we mentioned that the legs are machined and formed from PVC foam. But what exactly does that mean? Here (in gory step by step detail) is how we make them!
We’re pleased to announce our newest kit, the “Three Fives” Kit, a kit to build your own 555 timer circuit out of discrete components. Here’s a way to re-create one of the most classic, popular, and all-around useful chips of all time.
The kit is a faithful and functional transistor-scale replica of the classic NE555 timer integrated circuit, one of the most classic, popular, and all-around useful chips of all time. The kit was designed and developed as a collaboration with Eric Schlaepfer, based on a previous version (pictured here), and adapted from the equivalent schematic in the original datasheets for the device. There have been a few other examples of circuits like these (such as the one that we featured in our article about the 555 contest), but we really like how this one has come together.
The kit is designed to resemble an (overgrown) integrated circuit, based around an extra-thick matte-finish printed circuit board. The stand— which gives the circuit board eight legs in the shape of DIP-packaged integrated circuit pins —is made from machined and formed semi-rigid PVC foam.
To actually hook up to the giant 555, there are the usual solder connection points, but there are also thumbscrew terminal posts that you can use with bare wires, solder lugs, or alligator clips.
One of the really cool things about having a
unintegrated disintegrated discrete circuit like this is that you can actually hook up probes and monitor what happens at different places inside the circuit.
So that’s our new “Three Fives” Kit (shown above with an original NE555 for scale). It’s not quite as big as our 555 footstool, nor as tasty as our edible version, but it’s a great little circuit, and it’s got legs.
We’ve put together a roundup of our simplest LED projects; easy things to put together mostly with a bare LED and a coin cell.
Pictured above, Basics: Simple LED Pumpkins
Each of the paper segments is moved in or out by a servo motor to make the mechanical digital display. The whole thing is run off of an Arduino with a servo controller board and a clock module.
A low power CO2 laser cutter (like the one that we use) is fantastic for cutting and engraving wood, fabric, paper, and plastics. It’s also great for engraving painted or otherwise surface coated metal, like anodized aluminum (for example, making the labels on a Maglite).
However, with only a few exceptions, a laser like this generally falls down flat if you want to cut or engrave a chunk of bare metal. One exception is that you can actually cut through metal if it’s thin enough. Another is that you can make dark marks on metal with the help of a ceramic coating compound like CerMark. CerMark is sprayed on metal, then blasted with the laser so that it fuses to the surface, leaving a dark, permanent mark. Unfortunately, a spray can of CerMark costs $60, and as it is a specialty item, it may not be easily available when you happen to need it. So what do you do if you need something like this and you don’t have it?
Over at ZeptoBars, they have an incredibly detailed “take-apart” post on what’s inside the ULN2003 seven channel Darlington driver chip. The ULN2003 is commonly used for driving LED displays—you can find it, for example, in our Mignonette game.
We often receive comments that while out microchip photos are beautiful and interesting, it is completely unclear how integrated circuit implements basic elements and form larger circuit. Of course it is impossible to do a detailed review of an 1’000’000 transistor chip, so we’ve found simpler example: ULN2003 – array of Darlington transistors.
They’ve stripped off the outer housing and put it under the microscope. They then analyzed the photos to show you what parts make up the individual transistors, resistors and diodes inside the chip.
The first problem that we encounter when developing useful and practical educational resources for stent design is that every design we might want to use as an example is proprietary! That leaves us without much to talk about… So to solve this problem, the first step was to create a design to use as an example. The Open Stent is designed to be completely generic, but also realistic, and relatively easy to modify and extend to be useful for whatever purpose a designer intends.
In addition to publishing their draft of Open Stent Design, which they call “a practical guide and resource for design and analysis of a generic Nitinol stent,” NDC has provided extensive calculation tools and CAD files as well, to help others evaluate and create derivatives of the design.
The project is a fascinating open source hardware use case, where creating an open design provides a platform for education and discussion where none existed before. It’s also very exciting to recognize this as an early example of open source hardware in the field of medical devices— one of the places where open hardware can potentially make a very big difference in the world.