All posts by Windell Oskay

About Windell Oskay

Co-founder of Evil Mad Scientist Laboratories.

Does this LED sound funny to you?

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flickerLED - 01

flickerLED - 02

At first glance, these might appear to be normal 5 mm (“T-1 3/4”) clear lens ultrabright yellow LEDs. However, they’re actually “candle flicker” LEDs— self-flickering LEDs with a built-in flicker circuit that emulates the seemingly-random behavior of a candle flame.

In the close-up photo above, you can actually make out the glowing LED die on the left side, and a corresponding-but-not-glowing block on the right: the flicker circuit itself. In what follows, we’ll take a much closer look, and even use that little flicker chip to drive larger circuitry. Continue reading Does this LED sound funny to you? →

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Peggy2LE Light Painting

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Trazo de Colores / Colors Track

One of the joys of designing electronics is seeing the unexpected things that people do with your designs. Here’s one of them: Wulfrano Moreno sent us these fascinating light paintings that he made with a Peggy 2LE with an interesting pattern of LEDs installed.


1er Trazo Peggy

Here, you can begin to see some interesting interplay between the fast refresh cycles on the screen and the motion of the board. One might imagine that there’s still a lot of yet-unexplored potential there– with those red/green/blue/yellow/white stripes and high speed digital control, you could make almost anything.

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A Diamond Engraving Tool for Eggbot

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Driver board with pen arm

 

What is it? It’s a most useful little thing: a low-cost diamond engraving attachment for the Eggbot.

 

This turns a humble pen-plotting Eggbot into a full-on CNC-driven vibrated-tip diamond-point engraving tool, capable of light-duty marking and engraving on hard materials like glass, stone, and ceramic. Wooo!

Clear glass engraving Continue reading A Diamond Engraving Tool for Eggbot →

This entry was posted in CNC, Eggbot, EMSL Projects, Evil Mad Scientist Shop and tagged , , . Bookmark the Permalink.

A video introduction to the Digi-Comp II

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Several weeks ago, we talked about bringing our giant Digi-Comp II to Maker Faire. But now we’re back, and we wanted to show everyone how it works– not just the many folks who came by to see it at Maker Faire.

For those of you just joining us: The Digi-Comp II is a classic 1960’s educational computer kit– an automatic binary digital mechanical computer, capable of conducting basic operations like adding, multiplying, subtracting, dividing, counting, and so forth. These operations are all conducted by the action of marbles rolling down a slope, directed by mechanical switches and flip flops that act as logic gates. Our version is a modern, larger-than life remake. A functional clone, but sized up to use billiard balls instead of small marbles.

(The video is embedded here; if you can’t see it, click through to view it on YouTube.)

Full size

The machine is big at roughly 4×8 feet, and somewhat difficult to video or photograph. To get the overhead view for our video, we ended up moving the machine out to our loading dock and standing above it. The overview shot above required the further assistance of a ladder perched above the edge of the loading dock.

Digi-Comp II - 01

You can find additional photos of our giant Digi-Comp II in this flickr photo set.

See also our prior blog post about this machine, and, of course, digi-compii.com for future updates.

This entry was posted in Education, EMSL Projects and tagged . Bookmark the Permalink.

Advanced servo hacking: The one-ton linear servo motor

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One Ton Servo A

Hobby servo motors are the little wonders that make radio-control boats, airplanes, cars, hovercrafts, helicopters, submarines and robots work. And they are excellent devices for hacking.


Hobby servo motors each contain a little motor, which (through a set of gears) turns the output shaft, which is connected to a potentiometer, which provides position feedback to the controller chip inside the servo, which commands the motor to move until the output shaft reaches the desired position.
We’ve seen all kinds of crazy and wonderful servo modding– from the standard continuous rotation mod to the simple electronic speed controller, to full-on (servo) brain transplants.


Some time ago, I wrote up an article an article in Make Magazine, about how to modify a hobby servo motor to precisely control a one-ton scissor jack. The resulting sub-$100, one-ton linear servo motor can be used for any number of CNC and robotics projects. (For our own use, this was the Z-axis lift motor of the CandyFab 4000.)


We are now pleased to report that this project has just been released to the public over at Make Projects, where they have released a step-by-step version of the magazine article. (So go take a look!) One note: be sure to download the two PDF documents listed under “Files” — you’ll need those diagrams to follow along with the project.

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ISP Shield Kit, version 2.0

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ISP Shield 2.0

Earlier this spring, we released our open-source ISP Shield for Arduino. After using them for a while, we’ve found a few ways to improve the design, so today we’re releasing version 2.0.

ISP Shield 2.0

The ISP Shield is an Arduino “shield” (daughtercard) that makes it easier to use your Arduino as an AVR ISP programmer. It can be used to burn bootloaders onto new AVR chips, from directly within the Arduino programming environment, either in the on-board ZIF socket or on an external target board. More generally, it can also be used as a general-purpose AVR ISP programmer, using avrdude with the programmer type specified as “avrisp.”

ISP Shield 2.0

One of the tricky things about using the ISP shield is that there is a known incompatibility between Arduino-as-ISP and Arduino boards that have auto-reset capability. Version 2.0 of our ISP shield design fixes this, by adding the ability to temporarily disable auto-reset on the Arduino. Auto-reset override is an optional, jumper-selected feature that can be turned on and off.

(The other jumper shown above allows you to select whether or not the ISP shield provides 5V power over the ISP interface, a handy feature for programming chips on simple target boards.)

ISP Shield 2.0
The ISP Shield 2.0 is also our first printed circuit board to feature the OSHW logo— the first of many, we hope. :)

The ISP shield kit is available at Evil Mad Science, and complete documentation is available at the Evil Mad Science Wiki.

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Digi-Comp II and the 2011 Bay Area Maker Faire

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Digi-Comp II - 02

This weekend is the 2011 Bay Area Maker Faire, one of our favorite events of the year. This is our tenth Maker Faire, and we’ve created something very special to bring to the event: A modern recreation of the Digi-Comp II, in larger-than-life scale.

Digi-Comp II - 08

The Digi-Comp II is a classic 1960’s educational computer kit. It’s a fully functional binary digital mechanical computer, capable of conducting basic operations like adding, multiplying, subtracting, dividing, counting, and so forth.

Coolest of all, these operations are all conducted by the action of marbles rolling down a slope, directed by mechanical switches and flip flops, and all powered by gravity.

Most calculations are semi-automatic. For example, once you enter two numbers that you wish to multiply together (and set the appropriate configuration switches), you pull the start lever to release the first marble. Running the full calculation can take quite a few marbles. But, once the first ball makes its way through to the bottom, it releases the next ball from the top, and so on, until the calculation is complete– at which point it stops.

Digi-Comp II - 10

The original Digi-Comp II used 1/2″ diameter marbles.

For our “larger than life” model at Maker Faire, we’ve scaled it up to use billiard balls (specifically, 2 1/4″ diameter 8-balls). The overall size of the top deck of the machine is just under 4×8 feet. It’s made of CNC-routed plywood, and is sturdy enough that it might make a good museum exhibit someday.

Digi-Comp II - 04

You can see additional photos of the Digi-Comp II in our
photo set on flickr. We’ve also written up another blog post showing a video of our giant Digi-Comp II operating.

We are also pleased to announce that we are now planning to release a new kit version of the Digi-Comp II, at the original tabletop scale, perhaps as soon as this summer. Stay tuned for updates at digi-compii.com.

Some additional links that may be of interest:

  • The Friends of DigiComp group on Yahoo, whose members provided crucial photos and scans of the original Digi-Comp II, along with its documentation. This project would not have been possible without their help.
  • “How can they learn?“, an article by Jack Crenshaw in EEtimes, about the educational value of mechanical computers including the Digi-Comp II
  • “My first computer – the Digi-Comp II“, an article by Joshua S. Levine
  • The Digi-Comp I, predecessor to the Digi-Comp II, available as a reproduction kit from Minds-On Toys.
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Solving an old surplus mystery

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mystery

Several years ago, we came across this interesting artifactat one of our local electronics surplus shops, and couldn’t really make heads or tails of it. But after the passage of the aforementioned several years– along with several dozen interesting suggestions from our readers –we haven’t been able to get much closer to an answer.

But then, at this month’s Electronics Flea Market, we came across what appears to bea related chunk of hardware:

Ampboard - 2
Continue reading Solving an old surplus mystery →

This entry was posted in Electronics, EMSL Projects, Vintage Technology and tagged , . Bookmark the Permalink.

The Open Source Hardware Logo

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open source hardware logo

Following the public vote announced several weeks ago, the design above by Macklin Chaffe was selected as the v 1.0 logo for Open Source Hardware. We hope that this will, in time, become a recognizable mark indicating open source hardware projects and products.

Part of what will help to spur adoption is making the design available in a variety of formats, ready for use in different contexts. Already, we’ve seen versions in OpenSCAD (for 3D fabrication) and KiCad (for circuit board design).

To those examples, we’re adding our own: the OSHW logo, ready to use in gEDA PCB, our favorite software for circuit board design.

open source hardware logo

Here’s how the logo might look on a printed circuit board, as rendered in gEDA PCB.

open source hardware logo

We’ve also rendered it in a few sizes and styles– filled or not, and losing the text as the logos get smaller. You can download this set of examples for gEDA right here ( 82 kB .zip archive).

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