— Ryan Jenkins (@ryanejenkins) August 20, 2015
There’s nothing quite like the sound of a robot duet— a stepper motor quartet.
Super Awesome Sylvia has posted a video report from this year’s RoboGames. Highlights include a couple of combat matches, one of Sylvia’s LEGO competitions, WaterColorBot receiving a medal, and Sylvia completely geeking out after Grant Imahara interviewed her in the audience. (For extra fun, watch the raw footage of the interview from RoboGames.) Our STEAM shirt makes a cameo, too.
JK Brickworks made this amazing “pick and place” style Lego Mosaic Printer:
It is built entirely using LEGO parts. It first uses the EV3 colour sensor to scan the source image and save the data on the Mindstorms unit. It can then print multiple copies from the saved image data. The 1×1 plates used for ‘printing’ the mosaic are supplied using a gravity feed system and the printing head is simply a 1×1 round plate that can pick up and place the 1×1 plates.
More information about this project can be found at JK Brickworks.
3D printing is a common maker topic, and MakerCon brought a few different twists to it. Above is Gael demonstrating InMoov, an open source 3D printed humanoid robot. There was also an incredibly inspiring talk about applications for medical 3D printing by Dr. Glenn Green.
3D printing can be whimsical as well, as demonstrated by this “25 mm” drill bit by Gigabot.
The folks from Strawbees had built a quadcopter rotor cage with a clever servo actuator for flapping sculptural wings.
I enjoyed seeing this attractive laser cut living hinge at the BotFactory demo.
Rogue Rovers are electric semi-autonomous ATVs designed for agricultural use to reduce farm injuries and pollution.
More pictures from the event are in my flickr album.
Congratulations to our friend RobotGrrl, who took home a gold medal in the Best of Show category.
From the White House Office of Science and Technology Policy blog post, An Egg-straordinary Day of Science and Technology:
Interacting with EggBot, an art robot that can paint very intricate and precise designs on eggs. EggBot taught students about digital design, computer numerically controlled machines and robotics. This was also a fun way to celebrate National Robotics Week!
We’re excited to be attending and helping to judge robots at RoboGames this year. This epic competition includes not just combat, but also sumo, soccer, firefighting, and so many more. The event is April 3-5 and tickets are on sale now. Evil Mad Scientist readers can get $5 off with coupon code EMSL.
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.
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.