About Windell

Co-founder of Evil Mad Scientist Laboratories.

Using Artist Grade Materials with the WaterColorBot

watercolorbot paints

One of the questions that we’ve had on the WaterColorbot is about its ability to use higher-quality materials. And in particular, can you use it with fine (artists’) watercolor paints?

The WaterColorBot comes with a starter set of Crayola watercolors. This kind of paint set is great for kids and great for learning how to use the WaterColorBot. And in the United States at least, it’s also easy to obtain direct replacements from your local office or art supply store.

But on the other hand, watercolors like these do not offer the depth or range of color nor the archival quality that professional artists expect and require. And, replacement paint sets may not be so easy to find overseas, or even in less urban areas of the US. Fortunately, you can use the WaterColorBot with other paints, and we’re working on expanding the number of different ways that you can.

watercolorbot paints

The first, easiest solution is to note that the Crayola paint set actually comes with (well, in) a perfectly-sized paint palette; simply rinse out the remaining paint with cold water.

The empty Crayola palette can be reused with tube-based watercolor paints, which are available at art supply stores worldwide. Like dry (pan) watercolors, tube based watercolors are available in many grades, from very inexpensive to fine artists’ watercolor, and in a truly impressive range of colors.
watercolorbot paints

While the the empty Crayola palette is perfectly serviceable, it is a bit flimsy, and we are also planning to offer a couple of more durable permanent palettes as optional accessories for the WaterColorBot.

watercolorbot paints

Here is the first of those accessories: A milled plastic palette for use with tube-based watercolor paints. It’s tough and permanent with eight oval wells.

watercolorbot paints

For artists who prefer to paint from pans (dry paint), our second accessory is a palette that cradles up to eight “standard” half pans, which are one of the preferred shapes for artists’ watercolors. The word “standard” is in quotation marks because there is actually quite a range of variation in the size of half pans; this particular palette is sized for Winsor & Newton (and Cotman) watercolors. We also plan to offer other holders to fit half pans from other manufacturers.

And what about paper?

The WaterColorBot is designed to fit 9×12” paper, which is one of the most common sizes for watercolor paper. Heavier and finer grades of paper (140 Lb, 300 Lb) can be used without issue, and standard methods for affixing paper to the board– such as tape and tacks –will work just fine. Larger sheets of paper can be cut down to fit, and smaller paper– including A4 and US letter –can be used, although you may need to pay attention to the margins.

Drink Making Unit 2.1

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DMU 2.1 - 15

While we are better known for other types of art robots (like the Eggbot and now the WaterColorBot), we have also been involved with cocktail robotics for the past few years.

After a half-dozen cocktail robotics event over the past couple of years, we’ve had a chance to refit our famous bar-bot, Drink Making Unit 2.0, with a few well-earned upgrades.  Read on for the gory details!

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Introducing The WaterColorBot

Today we’re thrilled to be launching our newest kit: the WaterColorBot.

The WaterColorBot is a brand-new project from Evil Mad Scientist Laboratories and Super Awesome Sylvia — a friendly art robot that moves a paint brush to paint your digital artwork onto paper, using a set of watercolor paints.

We’ve previously written about how we got started on this project (in a guest post by Sylvia), and about Sylvia’s visit to the White House Science Fair, where she was able to give President Obama a personal demonstration of the WaterColorBot.

And now, you can get one too!  We’re launching the WaterColorBot today on Kickstarter, and we’d like to ask for your support in getting it out there.  The WaterColorBot is an enormously powerful tool for helping to get young people interested in technology:

Beyond simple fun, we think that the WaterColorBot has enormous potential for STEM and STEAM education, especially as a way to get young people engaged with hands-on technology and robotics. We are particularly interested finding ways to inspire young women to pursue careers in science and technology. We cannot imagine any better way to do so, than starting with a robot co-designed by a 12 year old girl.

Perhaps more than anything else that we’ve done, we think that the WaterColorBot really can make the world a better place, one (young) Evil Mad Scientist at a time.

A round up of our “Basics” articles

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Soft Circuit Merit Badge01  g22023

Over the course of the past few years, we’ve been writing occasional “Basics” articles, about introductory topics in electronics and microcontrollers.  In the spirit of making things easy to find, we’ve now tagged them so that you can find them with this link, and we’re collecting them together in this index that will be updated from time to time.

Our “Basics” articles about electronics in general:

Additional “Basics” articles about working with AVR microcontrollers:

Bullet Time Fireworks with a GoPro and a Ceiling Fan


Just in time for the Fourth of July, Jeremiah Warren created an incredible relatively low-budget “bullet time” rig— with a 240 fps GoPro camera mounted to a ceiling fan —to photograph fireworks. He posted a full writeup showing how to build it on his web site.



The clever hack about using the GoPro on the ceiling fan is thanks to Mark Rober, who showed how to do it back in May, mostly with smaller-scale subjects.  But Jeremiah has taken the idea and run with it, adapting it for larger-scale photography.

And as you can see, the results are simply fantastic.You can find more videos and the full how-to on Jeremiah’s site.

Open Discussion: Does Solder Expire?

Solder 4

When we recently wrote about looking at solder paste up close, we happened to mention that it has a shelf life— something that you might expect to be uncontroversial considering that there is an expiration date, printed right there on the jar.

But, our reader Trav commented

Very nice pics. What happens to solder paste when it expires? does it taste funny? Do the balls go flat?

I assume the paste rather gets runny and doesn’t hold the solder in place or it gets thick and won’t spread evenly.

I’ve heard of it expiring, but never knew how. I’ve had a tube of flux for 20 years now. When it gets too thick, I put in a couple drops of alcohol and it seems to work good as new.

We like the “balls go flat” theory!  But seriously, we presume that they wouldn’t label paste with a short shelf life— typically 4-12 months, when kept refrigerated, depending on the type of paste —unless there were a reason (and hopefully, a good reason) to do so.

A blog post on the Indium Corporation web site offers a little insight.  It turns out that the “activator” chemicals within the flux, which serve to clean oxides off of the surfaces that will be soldered, also interact with the microscopic solder balls, gradually scouring off their surface oxides.  When the solder particles are clean enough, they can actually cold-weld together, resulting in increased effective grain size and viscosity.  As Trav notes, adding a little alcohol can reduce the viscosity of flux, but we can see how increased grain size and other factors (such as having used up some of the activators) could affect performance in other ways.

But in any case, it sounds like there are a range of experiences out there, and we would like to open the question for discussion: What has your experience been with out-of-date solder paste? Has it worked just fine? And if not, what was the failure mode?


Solder 2
Separately, what about (flux-cored) solder wire?

Kester has this to say, in their policy about shelf life:

Flux cored solder wire has a limited shelf life determined by the alloy used in the wire. For alloys containing more than 70% lead, the shelf life is two years from date of manufacture. Other alloys have a shelf life of three years from date of manufacture.

So, our spool of lead-free solder pictured above, with date of manufacture 3/16/05 expired five years ago in 2008.  Presumably one reason for a stated expiration date is that the flux becomes less active over time as it interacts with the solder metal.

But in our personal experience, this kind of solder seems to generally work just fine, even many years past its nominal shelf life.

Solder 3

Many others seem to have had a similar experience with solder wire.

When we wrote about assembling a vintage Heathkit, we mentioned that it came with solder.  It actually came with two little packets of solder, specifically 60/40 rosin-core, cheerfully labeled “Made Expressly For Heathkit by Alpha Metals, Inc.”

Seeing as (1) the kit and solder date back nearly 40 years, (2) Alpha Metals also uses the three-year figure for shelf life, and (3) we already had a fresh, open spool of Alpha Metals 60/40 rosin-core solder in the lab, we opted to use the fresh spool and save the vintage solder packets for a rainy day.  Were we wrong to do so?   Certainly, some of our readers thought so:

Solder shelf life? Are you sure about that? Solder paste has a shelf life but I’ve never heard of a shelf life for a real coil of 60/40 rosin core solder. I’ve used some pretty old stuff myself, a quick Google search for solder shelf life found me a discussion where a guy is talking about using solder from the 60s with no problem on the first click!

So what has your experience been? Have you used “old” solder, and if so, how well did it work?

The 2013 Open Hardware Summit: Call for Papers Extended

OHS 2012

Good news if you’re still working on— or haven’t yet started —your proposal for this year’s Open Hardware Summit: The call for papers has been extended, so you’ve got another week to fine tune your talk, poster, or demo proposal.

Submissions are now due by JUNE 28, 2013.

The Open Hardware Summit is the world’s first comprehensive conference on open hardware; a venue to discuss and draw attention to the rapidly growing Open Source Hardware movement.  This year’s summit takes place on September 6 at MIT.


Previously: The 2013 Open Hardware Summit: Call for Papers,
The 2013 Open Hardware Summit: Tickets Now Available

Photo credit: Open Hardware Summit on Flickr.