The Evil Mad Scientist Thanksgiving Sale is running now through Monday. Coupon code TURKEY will get you 10% off sitewide, and we have a list of kits on additional discount on our specials page. Thanks for being our awesome readers and customers!
You’re invited to our annual open house!
When: Thursday, November 19, 5 pm ? 9 pm
Where: Evil Mad Scientist Laboratories
175 San Lazaro Ave, Suite 150
Sunnyvale, CA, 94086
We’ve just finished a major update to our store, giving it a much needed facelift and now much more mobile friendly. Woo!
This tiny little thing is a new EggBot accessory that we call the Wax Coupler. Not because it’s made of wax (it’s CNC machined aluminum) but because you can use it to attach an egg to the motor that turns it, using wax, like so:
Aside: why is the base of the egg black? We’ll get to that below.
Once the egg is attached to the Wax Coupler, it provides a rigid attachment point that provides secure coupling between the egg and the motor. More importantly, the coupler+egg assembly can be removed from the motor and put back in place, without losing registration. In machine tool terms, you might describe this as the process of attaching an egg to a rigid mandrel.
Wait– why would you want to do that?
Let’s go back a few steps. Last spring we introduced our Electro-Kistka for EggBot. A kistka is a hot-wax pen used in the traditional wax-resist and dye (batik) method to produce colorful eggs in the fashion of Ukranian pysanky, and this one is designed to work with a computer-controlled EggBot.
At the time, we noted that this process introduces a new problem, that of re-indexing the egg within the EggBot, after taking it out for dyeing:
It is harder than it looks. While two-tone eggs are straightforward, we have found it to be challenging to precisely reposition an egg after removing it for dyeing. Thus, it takes considerable patience and experience to produce multicolor eggs with good registration between subsequent color layers. We’d be interested in exploring better ways to do this.
One method that we tried (shown above) was to dye the egg in place, by brushing it without removing it. The results were mediocre: it worked, but the dye layers were subdued and blotchy. We also looked into a somewhat wackier method of dying the egg in place, by standing the EggBot on end, and using a collapsable bag of dye.
Which brings us to the proper solution: To attach the egg rigidly to a repositionable coupler with beeswax. Doing so allows us to take out the egg and dye it (coupler and all) and then easily index it back into the EggBot.
In October, we released our Solderless Flickery Flame project, based on a tiny breadboard with six red and yellow candle-flicker LEDs, to give a fun and semi-realistic flame effect. Today, we’re releasing two new Flickery Flame Soldering Kits along the same lines, each of which has 6 candle-flicker LEDs, a little circuit board, and a battery holder.
The Yellow/Red kit has the same mix of yellow and red candle-flicker LEDs that works so well in the breadboard kit. This one will look great in a jack-o-lantern, luminaria, or scale-model fireplace.
On the other hand, the White/Warm White kit has a mixture of (cool) white and warm white LEDs that give a modern wintery flame effect that has at least as much charm, but won’t be mistaken for a natural fire. This one will look great in all kinds of winter holiday decorations, luminarias, and props.
Both the Yellow/Red and White/Warm White kits are fun, low-cost, self-contained, and easy soldering kits, which will be right at home both as stocking stuffers and as bite-size first projects for soldering workshops.
The Exploratorium is holding their annual member holiday party and shopping night on Sunday, December 7 from 6-9 p.m. We’re excited to be there to show off some of our kits, including the EggBot, which will be available for sale. You must be a member to attend (need an excuse to become a member?), and RSVP by December 4.
We are very pleased to introduce something that we’ve been working on for most of this year: WaterColorBot version 2.0!
The WaterColorBot is our collaboration with 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.
Version 2.0 brings it to the next level with some greatly improved hardware. First and foremost, the carriage that holds the brush has been completely redesigned:
The carriage on the original WaterColorBot was made from laser-cut plywood, with nylon bushings and two simple delrin strips that formed the vertical flexure translation stage. (You can read more about the original carriage here and here.)
The new carriage consists mainly of two pieces of metal. The center block of anodized aluminum is CNC milled, and houses crossed linear roller bearings. Wrapped around that is a laser-cut and formed aluminum part that mounts the brush-lift motor, cable guide, and the flexure stage.
The new flexure stage is built with two custom flex circuit boards, used in this case as mechanical flexures. Each board consists of a very thin (0.1 mm, 4 mil) Kapton sheet with a thin fiberglass (G10/FR4) stiffener on its center section. With the two ends of each sheet clamped rigidly and the stiffener in the center, each flex circuit is to flex only along two well-defined lines. And with two boards, it forms a neat parallelogram linkage, without the slop that one might encounter in multi-part hinges. The net effect is that this new flexure stage has remarkable stiffness compared to the old design.
That stiffness, combined with the improved performance of the linear ball bearings makes this a more precise WaterColorBot. Not that you could even detect the improvement with a fat brush and watercolor paints, but things are looking quite good even with using ultra-fine point drawing pens, as you can see above.
The second major change is to the system of Spectra cords that the stepper motors control in order to move the carriage. Previously, the cords were guided around 11 plain bearings (stainless steel solid rivets) and 3 ball bearings. We’ve simplified this into an arrangement of just 8 ball bearings— four for each motor. The ball bearing pulleys have also been updated to use wide V-groove bearings that are easy to wrap the cords around.
Which brings us to the third (and last) major change. Thus far, WaterColorBot kits have shipped “some assembly required” — with all the major components built, but the cord lacing left to the end user. As of 2.0, WaterColorBot kits now come fully assembled and tested. That doesn’t make them any less hackable, but it does mean that you can get up and running faster.
Version 2.0 includes the same CNC machined aluminum winches that we introduced back in August. Tiny detail: we’ve carved a subtle indentation into the wood around the winch that makes them a little easier to turn by hand.
The new WaterColorBot kits will begin to ship right after Thanksgiving. And a bonus present for the holiday season: Version 2.0 is priced the same as the previous version, it’s just a whole lot more awesome per dollar.
Introducing our newest Hanukkah menorah kit: Mega Menorah 9000!
This is a great new easy soldering kit to make a handsome and decently-sized menorah. Once built, it stands just over 6 inches (15 cm) tall, and is 7.5 inches (19 cm) wide.
It’s USB powered, USB programmable with a built-in interface based on the Adafruit Trinket, and features 9 discrete RGB LED “pixels” that can produce all kinds of bright colors. Flickery flame effects built in too, of course.
One of the cool things about this kit is that it has a unique “Trompe-l’œil” circuit board design that gives some illusion of a rounded 3D surface. As you can see above, it’s actually flat as a board.
To make it, we started with a 3D CAD model of what we wanted the circuit board to look like. The outer contours of the model became the outline of the circuit board. We then rendered the CAD model, and used our StippleGen 2 software to convert the resulting image into a vector stipple drawing— one that could eventually be converted into the artwork for the circuit board. All together it’s over 9000 stippled dots of black silkscreen! (To be more specific, there are roughly 17,000 dots on each side.)
MM9k FAQ: OK, but isn’t the name “Mega Menorah 9000” perhaps just slightly on the excessive side?
Yes, we must (grudgingly) admit that it is. It just slipped out when we were trying to come up with a working title for the project — a name that meant “better than deluxe” so as to distinguish this model from our old favorite Deluxe LED Menorah Kits.
Alas, it was funny. And so it stuck. And now, it’s too late.
There are two circuit boards in the kit. The “top” PCB is shaped like a menorah and the components (mainly just the nine WS2812-style LEDs) are for the most part hidden on the back side.
The base circuit board has rubber feet, the control buttons (color, night, reset), an ATtiny85 AVR microcontroller, USB power/programming jack, and a programming indicator LED. The circuit is actually an implementation of the Adafruit Trinket, which allows for reprogramming the microcontroller without requiring any hardware other than a regular USB cable.
MM9k FAQ: Why is there a binder clip there?
It’s an assembly jig that helps to align the parts in place so that it’s easy to build and looks neat. We’ll write more about it later.
And, wow does this thing do colors! The nine WS2812-style individually addressable RGB LEDs in 5 mm packages, look reminiscent of candle flames, but can be tuned to just about any color in the rainbow. From a control standpoint, it’s awfully nice that they’re managed by just a single pin of the microcontroller, and have the built-in ICs to handle colors and dimming.
Mega Menorah 9000 begins shipping this week.