LED Metronome

After seeing our Larson Scanner kit, Martin shared this LED metronome project with us. Martin says:

It was designed as a “Visual Metronome”  So a learning music student could help see the timing by watching the green light.  There was to be an optional clicking sound  by using a small solenoid for the ticking – I chose that in place of a speaker for a more authentic sound.

The timing is a standard 555 timer which is fed to 7442 BCD to DECIMAL counter.  Next chip is a 74193 UP/DOWN counter.  When the count hits the last number, it sends a pulse to reverse the count or start over – depending on the toggle switch on the side.

There is also a pot on the 555 to control the speed.  All this was made in one night while I was working the graveyard shift.

The entire LED display was hand wired using a manual wire-wrap tool.

The chip pin labels on the back of the perf board are a particularly awesome relic of a different era of electronics assembly. Thanks for sharing your project photos and video with us!

DIY Snowflake Chocolate Molds with the Othermill

Our friends at Other Machine Co. have put out a mold making kit for the Othermill and posted an instructable for making snowflake chocolates using the online Snowflake Generator that Paul Kaplan of Inventables ported from our Vector Snowflake Application.

The process involves milling a wax positive for making a silicon mold. The beautiful two-tone chocolates are made by putting white couverture chocolate into the details of the mold, and then filling the rest of the mold with dark.

One more technique we could have used for Operation: CNC Snowflake!

Introducing WaterColorBot 2.0

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.

Mega Menorah 9000!


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.


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.


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.

CNC Dragonfly Barrette

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!

The DIYIC Protoboard

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.

Linkdump: November 2014

Ostrich EggBot 2.0

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.