Making A Core Rope Read-only Memory

October 9, 2013 by 30 Comments

[Kos] tipped us about an article he made presenting his experiences in designing and implementing a core rope memory. This magnetic read-only memory (ROM), contrary to ordinary coincident-current magnetic core memories (used for RAM), uses the ferrite cores as transformers. If you look at the picture above, you’ll count 7 of them. This sets the memory word size (7bits).  A new word is added to the memory by passing (or not) a wire through the ferrite holes. If you then pass an alternating current through this wire, a current will be induced (or not) in the other wire turned 30 times around the ferrite (alias transformer secondary).

In [Kos]’s setup, an input pulse of 5V generates output pulses of 15V. For demonstration purposes, he “wrote” a simple program that lights up digits in a seven segment display. Therefore, different numbers will light up depending on which wire he uses to pass the AC current.

These days core memory hacks are few and far between. But looking at this one, and the one we saw in August, makes want more. If you know of any others don’t hesitate to send us a tip.

SCARA Arm Becomes Enormous 3D Printer

October 9, 2013 by 17 Comments

SCARA

When you find an old, disused 80s-era SCARA arm in a lab, there’s really not much more you can do than make a giant 3D printer with it.

The last time we saw [Dane]’s salvaged SCARA arm, he had reconstructed the electronics by building his own servo motor controllers and feedback sensors. There were a few initial test prints, but the new upgrades to this printer make it much more useful, make it look even more kludged together, and made the prints even more accurate.

The largest upgrade to the new machine is an updated heated build plate. The previous plate used six 30W resistors. Good enough, but with two additional 245W membrane heaters, [Dane] can now keep his build plate at a constant 65 degrees C. Keeping such a large area warm requires a heated build chamber, so [Dane] came up with a giant semi-hexagonal box of warm made from aluminum extrusion, laser-cut parts, and acrylic frames.

Compared to earlier prints, the SCARA arm is printing some very nice parts including a battery holder for 40 LiFePO4 cells, and a beautiful propeller for a 3D printed boat. It’s an impressive build, made even more so by the fact this robotic arm was found during a lab cleanup.

3D Printering: You Want UV Resin?

October 9, 2013 by 56 Comments

printering

Just a few short months ago, 3D printing with stereolithography was an uncommon and very expensive proposition. Consumer-oriented SLA machines such as the Form1 and the B9Creator are as expensive as the upper echelons of squirting plastic printers and the community behind these machines isn’t even as diverse as the forums for the fly-by-night printers featured on Kickstarter every week.

This may be about to change with last month’s reveal of the Peachy Printer, a remarkably clever stereolithography printer that requires no special equipment, hardly any electronics, and costs $100. Even if the folks behind Peachy never ship a single unit, their clever engineering ensures that stereolithography will be a staple in the makers toolbox in the near future.

There is, of course, the problem of material. While plastic filament can be bought  just about everywhere, UV curing resin is a little harder to come by and much more expensive per kilogram or liter. Where then does the stereolithography experimenter get their hands on some of this magical material from the future?

Before we get to the article…

I’ve been writing a 3D Printing column once a week for a few months now, and I’m running out of ideas. If you have something in the 3D printer world you’d like to see covered in a little more depth than the standard Hackaday post, send in a tip. I’ll send you a few Hackaday stickers if it’s a good idea.

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A Motherboard For A WiFi Enabled SD Card

October 9, 2013 by 14 Comments

Over the last few months, a few very capable hackers have had a hand in cracking open a Transcend WiFi-enable SD card that just happens to be running a small Linux system inside. The possibilities for a wireless Linux device you can lose in your pocket are immense, but so far no one has gotten any IO enabled on this neat piece of hardware. [CNLohr] just did us all a favor with his motherboard for these Transcend WiFi SD cards, allowing the small Linux systems to communicate with I2C devices.

This build is based upon [Dmitry]’s custom kernel for the Transcend WiFiSD card. [CNLohr] did some poking around with this system and found he could use an AVR to speak to the card in its custom 4-bit protocol.

The ‘motherboard’ consists of some sort of ATMega, an AVR programming header, a power supply, and a breakout for the I2C bus. [Lohr] wired up a LED array to the I2C bus and used it to display some configuration settings for the WiFi card before connecting to the card over WiFi and issuing commands directly to the Linux system on the card. The end result was, obviously, a bunch of blinking LEDs.

While this is by far the most complex and overwrought way to blink a LED we’ve ever seen, this is a great proof of concept that makes the Transcend cards extremely interesting for a variety of hardware projects. If you want your own Transcend motherboard, [CNLohr] put all the files up for anyone who wants to etch their own board.

Ask Hackaday: What Is “Home Automation”?

October 9, 2013 by 48 Comments

homeAutomationCollage

We’re not entirely sure what’s become of the term “home automation.” The definition seems to have settled for any user interface in the home—via tablets, phones, handheld remote controls, etc. Some of these devices lack any form of automation and instead require manual input. Even Wikipedia’s home automation article suggests a move toward this trend, offering the following definition (emphasis ours):

It is automation of the home, housework or household activity. Home automation may include centralized control of lighting, HVAC (heating, ventilation and air conditioning), appliances, security locks of gates and doors and other systems, to provide improved convenience, comfort, energy efficiency and security.

Though “automation” is clearly included in the first sentence, one could interpret the bolded potion as meaning either:

  • Truly automated systems may also include centralized control (as a feature).
  • The category of home automation also includes systems that merely provide centralized controls.

So, are automated components optional? Judging by the phrasing of projects submitted to our tips line: yes sir. Truly automated systems exist, but if you browse through any home improvement store’s “home automation” section, you’ll be pummeled by a string of remote-controlled light dimmers and outlets. How many of these are designed to interact with sensors as feedback systems or otherwise function unattended?

Our articles often favor an “automation-optional” categorization. Should we, however, reserve the “automation” label for projects like the light switch based on room occupancy and deny other builds, like the voice-activated lights/outlets system or the RasPi lighting and audio control via web interface? Hit up the comments and help shed some light on how to properly use the terminology.

Troll Physics: 3 LEDs Powered By Hand

October 9, 2013 by 54 Comments

[Henryk] just sent us his latest episode of simple LED circuit puzzles. In front of the camera he solders one pin of each of the 3 LEDs to a different switch. He then puts the three assemblies in his hand and flips each switch to make the corresponding LED come on. We look forward to your explanations in the comments.

You may remember two other videos that [Henryk] made (also embedded after the break). The first video was a simple circuit with a resistor, three switches, and three LEDs in series. When a battery was connected, the LEDs were somehow switched on one at a time.The second video featured the same resistor/switches/LEDs, this time in a parallel circuit. Turning on the first switch made the first LED light up, and the second switch made the second LED light up.

Here are the few other troll physics projects we featured: the original LED circuits post, the super deluxe edition and the amazing solution to the trickery.

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Electric Bicycle Hack Is Hilariously Simple

October 8, 2013 by 40 Comments

Necessity may be the mother of invention, but limited resources give birth to some of the best hacks. [joejoeboom’s] 5-minute electric bike conversion probably can’t drive you into the next town, but it can scoot you around your neighborhood.

[jojoeboom] found a cordless drill at a local hardware store for $15, which he simply zip-tied to the bicycle’s frame. He positioned the drill so the chuck pressed firmly against the side of the bicycle’s rear wheel, creating a simple friction drive system. To create a throttle, [joejoeboom] strapped a spare hand brake to the handlebar and wrapped the brake’s cable around the drill’s trigger. Several carefully placed zip ties hold everything in place and allow the cable to tug at the trigger when the hand brake is squeezed.

Watch the bike poking around in a video below, and for some extreme contrast check out the 102-mph bicycle build from earlier this summer.

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