Category Archives: Engineering

Introducing WaterColorBot 2.0

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WaterColorBot 2.0

We are very pleased to introduce something that we’ve been working on for most of this year: WaterColorBot version 2.0!

WaterColorBot 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:

WaterColorBot 2.0

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.

WaterColorBot 2.0

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.

WaterColorBot 2.0

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.

WaterColorBot 2.0

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.

WaterColorBot 2.0

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.

WaterColorBot 2.0

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.

This entry was posted in CNC, Electronics, EMSL Projects, Engineering, Evil Mad Scientist Shop, Microcontrollers, Open Hardware, Robotics, WaterColorBot. Bookmark the Permalink.

How Computers Compute

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The Digi-Comp II we made for MIT is featured in this outreach video from MIT+K12 Videos by Jamie Teherani about how computers work. The mechanical switches on the Digi-Comp II are compared to first to light switches and then to transistors. Regarding manufacturing computers with transistors, Jamie says, “We can make them over a billion times faster than the Digi-Comp!”

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Mega Menorah 9000!

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MM9k

MM9k  MM9k

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.

MM9k

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.

MM9k  MM9k

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.

MM9k

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.

This entry was posted in Art, Electronics, EMSL Projects, Engineering, Evil Mad Scientist Shop, Microcontrollers and tagged , , , , , . Bookmark the Permalink.

CNC Dragonfly Barrette

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Dragonfly Barrette

When I saw Simone from Othermill running her machine this weekend, I told her about an idea I had for a metal dragonfly hair clip. She quickly grabbed the file from Sam DeRose’s Light-up PCB Pins tutorial. After carving the texture and doing the cutout, the only other tools needed to complete the project were a pair of pliers to bend the wings and some glue to affix it to a clip. It turned out great!

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The DIYIC Protoboard

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Introducing our new kit, DIYIC, which stands for “Do-It-Yourself Integrated Circuit!” This breadboard-style solderable proto board is shaped like a giant integrated circuit. It’s a freeform complement to our 555 and 741 “dis-integrated circuit” kits. Make your own custom 8-pin integrated circuit, use it as a giant connectorized breakout board for smaller components, or however you see fit.

Fine labeling

The matte-black circuit board is extra thick and has subtle white markings including an alphanumeric grid and pin number labels.

reverse side of PCB

The wiring pattern — that of classic breadboards — is easy to see by looking at the exposed traces on bottom of the board. Connections to the 8 terminal posts are through the three-position strips on the PCB; each is labeled with the corresponding pin number.

The DIYIC is available either as a bare circuit board or in a full kit, complete with the “Integrated Circuit Leg” stand and 8 color coded thumbscrew terminal posts.

This entry was posted in Electronics, Engineering, Evil Mad Scientist Shop and tagged . Bookmark the Permalink.

Ostrich EggBot 2.0

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Ostrich EggBot
Ostrich EggBot

We’ve just released version 2.0 of our Ostrich EggBot kit!  This is the giant size EggBot. Like the smaller models, it’s a machine capable of drawing on the surface of all kinds of spherical and egg-shaped objects up to 6.25 inches (15 cm) in diameter, including large ostrich eggs.

This chassis of the new version is CNC machined from melamine-faced MDF, and laser engraved with markings and calibration scales. (The previous version was made of plywood; you can read about it here.) We’ve also updated the graphics, and rolled in a number of subtle improvements based on user suggestions and our own extensive experience with the machine and other members of the EggBot family.

Ostrich EggBot Ostrich EggBot

With a relatively large chicken egg chucked into the holders, you can get a better sense of scale. (An ostrich egg is a terrible object to suggest a sense of size!)

The tailstock (the sliding portion of the right hand side) has been slightly redesigned for higher stiffness and better ease of use. The bulk of the stiffness in the directions that we care about (that is, in the directions where the chassis material is not strong) derives from the steel angle brackets, and the new tailstock helps to reinforce that for better overall rigidity.

Ostrich EggBot

One of the best things about the new chassis material is that it laser engraves particularly well, giving high-contrast, highly readable adjustment scales on the sides. And that makes it all easier to use in practice. All considered, this has turned out to be quite a nice little upgrade.

This entry was posted in Art, CNC, Eggbot, Electronics, EMSL Projects, Engineering, Evil Mad Scientist Shop, Robotics. Bookmark the Permalink.

Robot heart

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For Halloween this year, I went as a robot, wearing a silver dress with a slowly pulsing LED heart glowing visibly under the fabric.

Untitled

The LED is a one watt white LED, which we’re running at about 50 mA. It has a wide viewing angle, and the star-shaped mount lies conveniently flat. The LED is wired up to the PCB with a pair of twisted magnet wires. Magnet wire is flexible and thin, which makes it hardly noticeable under clothing. It is controlled by ATtiny2313 (running the code from our Mac sleep light pumpkin project) and powered by three AAA batteries. The PCB corners were rounded off so it wouldn’t be stabby.

Untitled

The dress was fully lined, which made it very convenient for mounting electronics. I pinned a makeshift pocket onto the liner, and tucked the battery holder and PCB in the pocket. I could feel the battery holder switch and turn it on and off through the fabric.

Untitled

The LED was taped to the dress liner with medical tape to hold it in place. An extra piece or two of tape held the wires to make sure there was appropriate slack for movement. (A note on tape: use the good stuff. The cheap paper tape in the off-brand first aid kit only stuck to itself and the magnet wire. 3M plastic medical tape worked great and came off easily.) This makes it easy to disassemble after Halloween.

LED heart

You can find more costume projects in our Halloween Project Archive.

This entry was posted in Costumes, EMSL Projects, Engineering, Microcontrollers and tagged . Bookmark the Permalink.

Pumpkin Faces for EggBot

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Pumpkin Face

renegade_geek posted a set of Pumpkin Faces on thingiverse for the EggBot. They’re cleverly arranged in layers so that you can hide and show the different eye, nose and mouth options.

A collection of separate eyes, noses and mouths, each set on its own layer, for a customized jack-o-lantern/ghost face to be printed with the Eggbot. These were made to print on ping pong balls. You may need to adjust for eggs and other less regularly shaped items. I have included a “faces menu” PDF so that you can clearly review your choices. This was really helpful in a classroom situation.

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Q and A with NanoBeam

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Nanobeam

When we saw NanoBeam on Kickstarter, we had a hard time comprehending just how small it is. So we asked Hyrum if he could send us some pictures for a better sense of scale, and he obliged. Yes, it fits in a tic-tac box. After seeing just how teeny-tiny a 5 mm beam is (one quarter the cross sectional area of Maker Beam and one ninth of Open Beam), our next question was “What the heck?” So we asked what made him think of making such a tiny beam.

I just wanted some tiny beams to build a small robot. I looked all over the place but couldn’t find what I wanted. After some research, and talking to some extruding companies, I designed a beam that was so small it challenged all the rules of this manufacturing science. I made a few on my cnc mill before I commissioned the die, to be sure it was what I wanted.

Nanobeam

How did you find a factory to work with?

I combed the web and talked to a lot of companies. I finally found one that focused on small extrusions. I saw the amazingly small and precise work they were doing for companies like Boeing and 3M and I knew I found the company I needed.

Nanobeam

What kind of fasteners do you use for something this small?

I used the largest screw I could but they are still small. The size is M1.2; you will find these in some pairs of glasses. I’ve got 3 designs for the nuts, I am waiting on manufacturing samples for the last one before I decide for sure which I will use.

Nanobeam

We asked what he thought NanoBeam would be useful for.

Immediately, I see this making a splash with small robots, quad copters and electronic enclosures.  I also see it being great for diy wearables, scale models and crafts. I recently got feedback from a guy that wanted to use them as a frame, conductor and heat sink for an LED array. I can’t wait to see something like that. I’m going to get some stock without the black coating for this application.

We’re also very interested to see what people do with such a tiny extrusion! Thanks to Hyrum for answering our questions. You can find out more, and check out his designs (Open Source Hardware definition compliant) at the NanoBeam website and the Kickstarter campaign page.

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