Dumb Terminals And Raspberry Pis

October 19, 2016 by Brian Benchoff 17 Comments

Back in the old days, the cool kids didn’t have an Apple II or a Trash-80. The cool kids had jobs, and those jobs had Vaxxen all over the place. The usual way of working with a Vax would have been a terminal, a VT220 at least, or in the case of [Sudos]’ experiments with a Raspberry Pi, A DEC VT510, a single session, text only serial terminal.

Usually, when we see a ‘new hardware stuffed into old tech’ project like this, the idea is simply to find a use for the old hardware. That makes sense; a dumb terminal from the late 90s should be a bit rarer than a Raspberry Pi Zero. This is not the case for [Sudos]’s build. He recently came across a few Raspberry Pi Zeros at Microcenter, and looking for a use for them, he decided to turn a serial terminal into a Real Unix System™.

As you would expect from a serial terminal, connecting a Raspberry Pi and putting some awesome character graphics on the screen is as simple as a Max3232 board picked up from eBay, a WiFi dongle, and an Ethernet adapter. Connect the Pi to the terminal with a serial adapter cable, and you’re off to the races.

While the VT510 serial terminal is just about the end of the line as far as dedicated terminals go, there are classier options. The VT100 terminal, older than most of the Hackaday readership, features a port on its gigantic board, meant to connect to whatever weirdness was coming out of Maynard in the late 70s. You can attach a BeagleBone to this connector, making for a very slick stealth mod.

Teardown A Classic : Tektronix P6042 Current Probe

October 16, 2016 by Gerrit Coetzee 6 Comments

[Paul Rako]’s teardown of his treasured P6042 current probe shows why Tektronix commands so much respect among the old hats of the electronics world.

Built in 1969, the P6042 is pretty sparse transistor-wise when compared a modern sensor. The user would clip the current probe, permanently attached to the case since the circuit was tuned for each one, over a wire and view the change in volts on an oscilloscope. When the voltage division on the oscilloscope was set properly the current in a circuit could be easily seen.

The teardown is of a working unit so it’s not completely disassembled, but it also sits as a nice guide on refurbishing your own P6043, if you manage to snag one from somewhere. Aside from capacitors and oxidized switch contacts there’s not much that can go wrong with this one.

As for how it compares, the linear power supply, analog circuit design, and general excellent engineering has the P6042 coming in with a cleaner signal than some newer models. Not bad for a relic! Do any of you have a favorite old bit of measurement kit?

Blinking An LED – Extreme Edition

October 13, 2016 by Nava Whiteford 57 Comments

This hacker’s video on blinking LEDs never got the recognition it deserves. At the time of writing clocking in at just 61 views, but it is indeed a work of art. Just trust me, scroll to the bottom of the article and watch it, you wont be disappointed.

Not convinced? OK, let me tell you about it and the world it has opened up in the Japanese maker scene. We’ve all blinked an LED. Maybe it was just to test a microcontroller, like the simplest Arduino example.

Or we’ve been a tad more old school and used the classic 555 to do it. Or maybe like me, you went through a phase of hacking together Phase Shift and other oscillators because well… it’s fun!

But [Junichi AKITA] has more extreme tastes, deciding that a custom IC layout is the way to go. [Junichi] designed a ring oscillator composed of flip-flops, then hand laid out each MOSFET placing each layer exactly where it should be fabricated.

The resulting design was then fabricated by an academic shuttle service in Japan (a bit like the well known MOSIS service). The result is a tiny circuit in the top right corner of the IC. Which of course [Junichi] then had to wirebond (check the video for a cool 1980s style Westbond machine which are still hugely popular in Japan).

IC Layout… by hand!

Optical image of the fabricated circuit.

[Junichi] bonded the die directly to a PCB (COB). I assume, purely for irony, a 555, and ATtiny based oscillator were also laid out on the board.

I guess you might have a couple of lingering questions. First you’ll likely bemoan your lack of your own fabrication facility (I’m still eyeing those used 1 micron fab lines that crop up on eBay from time to time). And secondly you might be asking yourself… why?

Both these questions are somewhat answers by the MakeLSI project. This growing project in Japan seems to have opened up semiconductor fabrication to all kinds of projects.

While my Japanese isn’t good enough to fully understand what’s happening it’s clear there are many awesome projects going on. Including joys such as IC layouts designed in vector graphics packages (Inkscape) and die images packed with interesting layouts, anime characters and QR codes.

For more awesome images and information (unfortunately all in Japanese) you can check them out on Facebook or on their homepage.

Continue reading “Blinking An LED – Extreme Edition” →

Measuring capacitance with wax dielectric

How To Measure The Dielectric Constant For DIY Capacitors

October 12, 2016 by Steven Dufresne 7 Comments

Every now and then you need to make your own capacitor. That includes choosing a dielectric for it, the insulating material that goes between the plates. One dielectric material that I use a lot is paraffin wax which can be found in art stores and is normally used for making candles. Another is resin, the easiest to find being automotive resin used for automotive body repairs.

The problem is that you sometimes need to do the calculations for the capacitor dimensions ahead of time, rather than just throwing something together. And that means you need to know the dielectric constant of the dielectric material. That’s something that the manufacturer of the paraffin wax that makes it for art stores won’t know, nor will the manufacturers of automotive body repair resin. The intended customers just don’t care.

It’s therefore left up to you to measure the dielectric constant yourself, and here I’ll talk about the method I use for doing that.

Continue reading “How To Measure The Dielectric Constant For DIY Capacitors” →

Resurrecting The Retro-futuristic Poly-1

October 11, 2016 by Nava Whiteford 11 Comments

[Tez] has acquired and resurrected a piece of New Zealand computing history, the Poly-1. To anyone who went to school in 1980s Britain, the Poly-1 appears to be a cooler, mirror universe version of Acorn’s BBC Micro. Like the humble Beeb, the Poly-1 was designed primarily for educational use. It also used a related, but superior, microprocessor (the Motorola 6809).

However while the legacy of Acorn lives on in the ARM architecture, only a few thousand Poly-1s were ever sold and it appears to have been largely forgotten.

The Poly-1’s demise was likely in part due to its high price tag — around $5,000 USD — its lack of support within New Zealand, and the difficulty that the small New Zealand company had breaking into international markets: issues which eventually killed off many similar 1980s computer companies in the UK, Japan and elsewhere.

But it’s still fascinating to look back, not just in nostalgia, but in admiration of the intrepid 1980s hackers who created these beautiful machines and the dream of a world that might have been.

[NE555]’s SMD Prototyping Is A Work Of Art

October 10, 2016 by Nava Whiteford 104 Comments

ne555_20yearsold — One of [NE555]’s boards from the 90s.

Over on twitter [NE555] has been posting beautiful SMD prototypes.

Back in the 90s when surface mount components gained widespread adoption, the quick and cheap PCB prototyping services of today were unavailable. This led many to develop their own approaches. In Japan a particularly novel and beautiful approach was, and still is, somewhat popular. [NE555]’s work is a excellent example of this technique using a fine enameled wire (you can find this on eBay as “magnet wire”), wirewrap board, and careful hand soldering. [NE555] has made a great video on the process (which you can watch below).

Continue reading “[NE555]’s SMD Prototyping Is A Work Of Art” →

Slide Viewer Upgrade Is A Bright Idea

October 9, 2016 by Kristina Panos 6 Comments

[cunningfellow] has been putting LEDs in everything lately. That’s understandable. Most recently, he used them to drastically upgrade his father’s super-cool mid-century slide viewer.

The slide viewer used to use a flashlight bulb, but it didn’t light evenly at all. Not only that, it produced a dim, orange-ish light. [cunningfellow] happened to have an old Nokia N93 lying around and decided to cannibalize that strange, beautiful, swiveling flip phone for its backlight circuitry. Unfortunately, the 4 LEDs aren’t going to run on a pair of C cells like the flashlight bulb did. [cunningfellow] needed some kind of boost converter.

He found one in the form of a Nokia E73 LCD driver board created by [Andy Brown]. The LEDs are way brighter than that old incandescent bulb, and they draw about 10mA less to boot. We think [cunningfellow]’s father will be happy with the result.

If you have an old slide viewer and no slides, try using it as a project case. If this post makes you miss your View-Master (also understandable), you can always turn your phone into a stereopticon.