Category Archives: Open Hardware

Open Source Beehives

The Open Source Beehives project is currently running a crowdfunding campaign with the goal of gathering information from sensor equipped hives throughout the world to help solve bee population problems like colony collapse syndrome. The sensors can also be used by individual beekeepers to monitor the health of their hive.

Even without the sensors and the citizen science, their hive designs are beautiful.

Basics: AVR Target Boards and Arduino Compatibility

Gary writes:

I have fallen in love with your Diavolinos – thank you!
My question: does the “Simple target board” allow for the 6-pin FTDI Friend hookup to upload sketches? This is quick and easy with the Diavolino. I’m new to reading circuits and stuff, and I cannot tell looking at the target board. It says to use in-system programmer, but I prefer to not buy another interface. Thanks!

Excellent question! It is certainly possible, but not as quick and easy.  Both the Diavolino and our ATmegaXX8 target boards boards use the same chip, usually the ATmega328P.  But, one might say that our ATmegaXX8 board is a simple AVR target board optimized for use with an AVR ISP programmer (like the USBtinyISP), whereas the Diavolino is a simple target board optimized for use with the FTDI interface.

XX8 Target Board

Versus a “bare” target board (with just the chip and power), there are four things that you would normally add, in order to use the FTDI interface to upload a sketch from within the Arduino environment:

Continue reading Basics: AVR Target Boards and Arduino Compatibility

MakerBeam Comes of Age

makerbeam pieces

Back in 2009, we helped support the launch on Kickstarter of MakerBeam, a miniature open source aluminum T-slot profile construction set. Just a few months later, we wrote about receiving our first batch of MakerBeam parts.  And while there were some good things that might be said about those first-batch parts, there were some not-so-good things as well. For example, custom screws that couldn’t really be tightened and fastening plates made of too-brittle plastic. With some improvement — stainless steel brackets — MakerBeam eventually found limited distribution in 2011 at Sparkfun in the USA and at, but on the whole, it seemed to be fizzling out of existence.

But, things change, sometimes for the better.  In 2012, Terence Tam’s excellent OpenBeam (a slightly larger T-slot profile, also currently sold by came roaring out of the gate, reminding us of what great things one can build out of extrusion profiles.  Meanwhile, the folks from took hold of MakerBeam and began to run with it — turning a languishing project into an open source hardware success story. They recently sent us a starter kit to review, and we have to say— we were blown away.

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To begin with, they redesigned the profile itself.  The basic proportions are still the same (10 mm across), but the new shape has a thicker solid core that improves strength, and now allows the ends to be tapped. (The hole does not go all the way through.)  They also started having their profiles anodized, providing a harder outer surface, and tapping the ends.

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Next up: Nicely made stainless steel angle brackets and fastening plates.  Rock solid when bolted down, although (things being small) you may need to use several of them to get the kind of rigidity that you need for certain applications. We already had some of these shapes from the original MakerBeam makers.

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Silly: Some of the fastening plates (the ones designed by the original MakerBeam team) are inscribed with the angle in fractions of Tau, as in τ/4 instead of 90°.  Our guess: it’s certain to please many fewer people than it annoys.


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And, most important: A fastening system that really works.  These stainless steel M3 screws with modified pyramid-shaped button socket cap heads are simply fantastic.  They slide easily into and out of the MakerBeam slots, and lock into place perfectly with a simple hex nut on the exterior.

There are arguments to be said for and against putting screw heads in the channels, but if you’re going to do it, you had damn well better do it right. And, finally, someone is doing it right.  You can read about the evolution of the fasteners on the blog, here, here, here, here, and here.


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Old components, Left side:  MakerBeam profile 1.0, old-style screws, machined ABS fastening plate.
New components, Right side: MakerBeam profile 2.0, new screws, stainless steel fastening plates.

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So, after nearly five years, MakerBeam has come of age, and finally fulfilled its promise of being a really nice miniature construction set.  Our congratulations and thanks to for doing such a great job of this, and especially for making these sets available for everyone else.

Hackerspace Field Trip

Photo by David Prewitt

From the Lenoir News-Topic, middle school students got to build Egg-Bot derivatives at their local hackerspace:

“I think this is one of the best field trips I’ve ever been on,” one of the sixth-graders said, unprompted by any of the adults (or reporters) in the room. “This one, you actually build something.”

The Winch Cutting Jig

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In our recent article, The Making of the WaterColorBot, we walked through the manufacturing process of the WaterColorBot, in which we make use of a number of specialized jigs, with varying levels of complexity.  We also left a teaser:

“The winch is also assembled from laser-cut wooden parts. The lower part has the shaft collar that mounts to the motor shaft, and the upper part has two halves that disassemble for cord management. It turns out that the winding-drum part of the winch needs to be quite round and concentric with the motor shaft for smooth operation– smoother than we can get with the laser. We solve this with our very-most-complicated assembly jig….”

And here it is.
Continue reading The Winch Cutting Jig

Decorating Christmas Ornaments with the Eggbot


Despite what you might guess from the name, our Egg-Bot kit is not just for eggs.  In fact, it turns out to be a pretty freaking amazing machine for decorating and personalizing your own Christmas ornaments!

Today we’re releasing the “Eggbot Holiday Super Pak” — a set of Eggbot-ready holiday ornament designs to give you a head start.  The set includes the designs above and many more.  It’s free, available for download as part of our EggBot Example set (on our GitHub releases page), and will be periodically updated as we add more designs.

Read on for some additional tips and tricks for using ornaments in the Eggbot!

Continue reading Decorating Christmas Ornaments with the Eggbot

WaterColorBot Software and Documentation

We’re wrapping up this week’s updates on the WaterColorBot project with some notes about software and documentation.


Our guides for setting up and using the WaterColorBot are already extensive, and still growing. You can find them at the Evil Mad Scientist wiki, or get there with a shortcut:

getting started booklet
Getting Started with WaterColorBot
One of the most important parts of the WaterColorBot’s documentation is our booklet “Getting Started with WaterColorBot.” The booklet covers the process of assembling the WaterColorBot kit, basic usage, an overview of software options, and a host of tips and tricks. It’s available on our documentation site in PDF format.
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Assembly video
We’ve put together a setup video, walking through the steps of putting together the WaterColorBot kit. The video is strictly optional, and covers much of the same ground that the booklet does. You can watch it at, or find it linked from our documentation page.



There are, at present, three primary applications that you can use to control the WaterColorBot, each of which has unique advantages.

RoboPaint RT
RoboPaint RT
The simplest of the three programs is RoboPaint RT, which is the one that we featured in our Kickstarter video. RoboPaint RT is a “real time” application that allows you to paint with the WaterColorBot. It’s straightforward and manual: Click on a color in the paint palette to change to that color, click on the water to dip the brush in the water, and drag the brush to paint on your paper.

With RoboPaint RT, you can also replay your drawing to make multiple copies, and save the file to open up and print again later. This program can be a lot of fun to play with and is a great way to get acquainted with the WaterColorBot. For those with good artistic skill, it can also be a remarkably powerful program.


Next up is RoboPaint, another stand-alone application written by the WaterColorBot team. In RoboPaint, you can open existing artwork in SVG format, snap the colors to your paint palette, and paint the document. It also has a rudimentary edit mode that lets you create new drawings to print. If you’re starting with existing SVG artwork, RoboPaint is generally the best of the three programs to use for a few different reasons. Most importantly, it’s good at automatically filling in large solid regions of a painting.


Inkscape drawing
Inkscape, with extensions
The third primary application is Inkscape, a superb, free vector graphics editor, for which we have written an extension (a plugin) to control the WaterColorBot. Our extension provides fine grain control over exactly what will be painted, but more-or-less requires that you create the artwork within Inkscape to take full advantage of the features.

Above, the drawing used to make the Robo-painted thank you cards that we wrote about earlier this week.

Inkscape is also capable of importing artwork in PDF format (as well as tracing bitmap graphics to some extent), and saving as SVG graphics that can be used with RoboPaint. If you’ve ever used an Eggbot (and its Inkscape based driver) you might want to start here, before trying the other apps.

And if you like to code…
For developers (and people who just like to tinker with code), there are additional options:

– Rolling your own, starting with our examples. RoboPaint RT is written in Java/Processing, RoboPaint is written in JavaScript, and the Inkscape extensions are written in Python. These can provide a nice starting place, in a few different environments.

– Direct serial control. The “EBB” motor controller board used on the WaterColorBot can be independently controlled from any environment that can send serial data to your USB ports.  Its command set documentation is here.

– The RESTful API. RoboPaint includes the “CNCserver” API for WaterColorBot, documented here. You can use this interface to control the robot locally (from your computer) or remotely (from anywhere on the internet, if you enable the remote option within RoboPaint and tell the other computer what your IP address is). Currently this is a low-level API; we are working on a higher level version where you can simply send an SVG file for RoboPaint to process and paint.


WaterColorBot kits are shipping now, and we are still taking pre-orders for December shipment. 

The Making of the WaterColorBot

What goes into making a WaterColorBot?  A lot, it turns out.

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It all starts with a 4×8 foot sheet of Oregon-made maple-faced hardwood plywood. We mount the sheet on CNC router for a process that involves five tools (ranging from 0.086″ to .375″ in diameter) and about 2 1/2 hours of cutting time. We can fit 20 WaterColorBot frames, complete with their feet, on a single sheet of wood — efficiently tiled with very little waste.  It’s also time efficient: Just under 8 minutes per frame.

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The parts are held into the sheet by little tabs, so that they don’t go flying out during the machining process.  We chisel them out of the sheet and inspect them prior to sanding.  At this point the parts are carefully shaped and detailed but still rough to the touch around the edges.

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Next up, sanding. Sanding removes the tabs and smooths the edges and surfaces to the touch. We use a combination of belt, disc, handheld power sander, and hand sanding for the various surfaces. All told, sanding all of the parts takes a little more than than twice as long as it does to cut them out of the sheet. (That might sound backwards until you watch how fast a CNC router moves compared to a human operating a sander.)

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After sanding, the parts are clean and smooth, ready for engraving.

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A special jig holds the four frame pieces in the laser for engraving. There are two passes, one for the primary markings, and one for the defocussed (blurry, dark) “WaterColorBot!” title text. We also engrave the back side of the top pieces (with a separate jig) with credits and the serial number.

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Stacks and stacks of WaterColorBot frame parts, before and after engraving.

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The surfaces of the WaterColorBot are covered with a number of stainless steel rivets — either bare or with a ball bearing –that guide the Spectra cord around the frame as pulleys. We individually press-fit them into place with a small 1/2 ton arbor press.

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The arrays of the four frame pieces– CNC cut, sanded, laser-engraved, and with their rivets press-fit — are now ready for assembly.

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We use another specialized jig to hold the four frame pieces rigidly in place while screwing them together with a torque-limited electric screwdriver.

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There are two types of “feet” that get mounted to the frame. The two left feet (always a fun term to use!) have holes in them to route the motor wires, while the two right feet do not. The feet are attached with wood glue, with the help of (yet) another specialized jig.

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After that, we mount the back-side cable guide support, and queue the frames up for having their motors attached and final inspection.

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The lower-deck pieces (“spoilboards”) are cut from 3/8″ MDF on the CNC router, in a much, much simpler process. They too are sanded and laser engraved, prior to having their paper clips mounted and being queued for inspection and shipping.

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Next up: The WaterColorBot carriage. The base of the carriage consists of six pieces of laser-cut 1/4″ plywood. We found a very fast process of attaching these together, which is to clamp the box together with two perpendicular sets of thumbscrews and thumb-nuts (color coded as you see), and to wick in cyanoacrylate (super glue) between the surfaces at a few key points. It takes only a minute to assemble one; much faster than we were able to do with fasteners or wood glue.

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After mechanically drilling pilot holes to mount the servo motor, we assemble the rest of the carriage: Four bushings, two flexures that form the vertical linear stage, the servo motor, and the brush holder.

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And then finally the 36″ servo extension cable and a laser-cut delrin cable guide, that prevents the cable from dragging on the paper. All neat and tidy.

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The winch is also assembled from laser-cut wooden parts. The lower part has the shaft collar that mounts to the motor shaft, and the upper part has two halves that disassemble for cord management. It turns out that the winding-drum part of the winch needs to be quite round and concentric with the motor shaft for smooth operation– smoother than we can get with the laser. We solve this with our very-most-complicated assembly jig, which we’ll write about separately, if there’s interest.

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In the kit, the winches come pre-wound with the appropriate length of 100 pound Spectra cord. We actually use an Eggbot as our tool to wind the cord. We mount the “spool” to one of the Eggbot stepper motors, and spin that motor (very quickly) for a set number of full revolutions to wind a fixed amount of cord onto each winch, using a modified version of the WaterColorBot software. Each winch is wound with about 125 inches of cord, in just nine seconds.

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A box full of wound winches, ready to be added to our accessory bags.

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The steel shafts that move the carriage came as 3 foot long rods, in a wooden crate the size of a coffin. We sent them to a local machine shop to be cut to length, after which they looked much neater.

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We ended up purchasing four hundred sets of Crayola Washable Watercolors. After we received our giant drop shipment from Crayola– which was unreasonably fun, in a grade-school sort of a way –we stacked them all on the table to take a photo.

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The paints, along with most of the other WaterColorBot accessories– wound winches, water dropper, velcro straps, power supply, and USB cable –get packed up in a pouch that will go in the shipping box.

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Our “getting started” booklets — printed and stapled. (We’ll be talking more about documentation in our next update.)

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Our shop cat, Zener, has not actually helped out with production whatsoever. She did, however, manage to get her tail caught in the output roller of our (warm and tall) laser printer a couple of days ago, leading to a little down time while printing those booklets. (Cat is OK, less some fur. The printer is still recovering.)

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And then, there’s final inspection. All the parts come together (with a giant checklist) in a padded carrying case with a reinforced handle.

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The carrying case has a silkscreened cover. The metallic silver printing ink that we used for the first two batches looks really cool, but becomes invisible at a certain angle. So, we’re switching to an aqua blue for the next batch.

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The completed WaterColorBot kits go in an outer shipping box, that keeps the carrying case safe for transport. It’s surprising how much of a warehouse you can fill with stacks of boxes!

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WaterColorBot kits are shipping now, and we are still taking pre-orders for December shipment.