Wire Wrap 101

You might notice that many of my writings start with “Back in the day”. Not wanting to disappoint I will say that back in the day we used to use wire wrap technology when we needed a somewhat solid, somewhat reliably assembly. Given a readable schematic a good tech could return a working or near-working unit in a day or two depending on the completeness and accuracy of the schematic.

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Properly done a wire wrap assembly is capable of fairly high speed and acceptable noise when the alternative option of creating a custom PCB would take too long or not allow enough experimentation.  Wire wrap is also used in several types of production, from telco to NASA, but I am all about the engineer’s point of view on this.

My first wire wrap tool and wire wrap wire came from Radio Shack in the mid 1970’s.  I still have the wire, because frankly its kind of cheap wire and I use it when it’s the only thing I can reach quickly when I need to make a jumper on a PCB. The tool is still around also, given the fact that I can’t find it at the moment the one shown here is my new wire wrap tool which is good for low quantity wrapping, unwrapping and stripping.

ww-tool2The skinny little wrap tool is okay for hobbyist as the wraps are fine with a little practice.  But I do recommend investing in high-quality wire.  A common wire available is Kynar® coated, a fluorinated vinyl that performs well as an insulator.

Before I go too much further, here’s the video walkthrough of wire wrap, its uses, and several demonstration. But make sure you also join me after the break where I cover the rest of the information you need to start on the road to wire wrap master.

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“Zero overhead” Z80 computer focuses on performance

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There’s something quite satisfying about building your own computer. Nowadays, constructing your own desktop PC is relatively easy, so if you really want to get your hands dirty, you have to take a step back in time and give some vintage hardware a spin.

[YT2095] has spent a good portion of the last two months building a computer based on the classic Z80 CPU. His machine, called “Z Eighty Development” or “ZED” for short is an amazing build, and most definitely a labor of love. He has put an estimated 700+ hours into this machine and it’s a beaut! When closed, the machine is pretty unassuming, but once he folds down the keypad, you can see that all of his time has been put to good use.

Most of the board’s components are connected together via wire wrap, including the large 48k memory card he built, as you can see from the link above. The wide array of add on cards all work together to accomplish his goal of “zero overhead” – freeing up the Z80 from having to do any unnecessary processing, such as I/O, etc.

It’s quite an impressive build, and ranks up there with some of the best Z80 based computers we have seen through the years.

Electromechanical computer built from relays

This is Zusie, a computer built out of electromechanical relays. [Fredrik Andersson] picked up a lot of about 100 telephone exchange circuit boards, each with about 16 relays on them. After getting to know a heat gun really well he ended up with 1500 working relays with which to play. The machine runs slowly, it iss noisy, but it definitely works. After the break you can see it running and assembly code program that he wrote.

The instruction set is based on boards running microcode. These store the operational commands for each instruction the processor has available to it and they run in parallel with the rest of the operations.

We’re always surprised to see that these home-built processors work. Mostly because of the complexity involved in assembling them. How hard is it to find a shorting connection or a malfunctioning relay? Those problems aren’t limited to this application either, what do you do if a transistor-logic CPU has a malfunctioning chip?

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Wire-wrapping an LED matrix

Regular reader [Osgeld] built a 1024 LED display matrix. This is a proof-of-concept design and he admittedly has overloaded the components. Most notably, the 595 shift registers (featured over the weekend) are sourcing too much current if all eight pins are active. That’s easy enough to fix in the next design by moving up to cascading LED drivers. Instead of soldering every connection in the display, [Osgeld] soldered the components in place and then used wire wrapping to make the point-to-point connections. This must have saved him a ton of time and frustration. We can’t wait to see what comes out of this first prototype.

Automated guitar pickup winding

[Robert Pickering] shares his automated guitar pickup winder with us. He built it for his senior project at Old Dominion University. Two stepper motors are used to wind the magnet wire around the pickup hardware. The unit is PIC based and about six minutes into the video (embedded after the break) you can see that he used wire wrapping for this build. Curious, one of the comments on our latest Hackaday Links mentioned that wire wrapping was rarely used anymore, but here it is anyway.

We especially like the limiting switches he’s using on the traverse mechanism. There are momentary push buttons on either side of a carriage which are depressed when a drywall screw in the sides of that carriage hits them. This makes for very easy calibration because the screw can be raised or lowered with just a bit of screwdriver work. Well built and documented, we’re sure he’ll get some high marks on this one. Continue reading “Automated guitar pickup winding”

Hackaday links: April 18, 2010

Remote motion control

This project walks though a method of controlling motors with an accelerometer when the two are physically separated. Two Arduinos are used, with the user interface and the motor control connected via Ethernet. This must be useful for something; maybe it should be the next step once you get your accelerometer up and running.

CNC machine build

[Lucassiglo21] is doing a great job documenting his CNC build. The project has been ongoing for several months. He’s seeing some success with milling simple PCBs along with other millwork projects.

Condom starts a fire

Ever needed to start a fire and had nothing on you but a condom? Yeah, we haven’t either but that doesn’t diminish the fun of this whimsical ‘Condom Hack Pack‘ video. See the uses you never thought of for those rubbery package protectors.

Solderless PCB

Print your component locations on a piece of card stock and populate the board without any soldering? This is quick and convenient for a circuit that doesn’t need to last very long. It uses wire wrapping to connect the components, completing the circuit. [Thanks Frogz]

BMOW: a home made cpu

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Building your own CPU sounds like quite a daunting task as it is. Building your own CPU using manual wire wrapping transcends difficult to become an art form. [Steve] has built a CPU by manually wrapping every single wire. That’s 1253 wires, or 2506 wrapped ends. Even if it didn’t work, it would be nice to look at. But it does work, you can see a demo video showing the audio functions after the break. The system is now enclosed in an Acer x-terminal case, so it isn’t as pretty, but its still quite a project. You can follow along as he builds each section, the video, sound, even the keyboard interface. It’s pretty amazing seeing it all broken down to the most basic forms.

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