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We added some new M3 screw lengths to our catalog: 6 mm, 10 mm, 12 mm, 14 mm, 16 mm, and 20 mm. (We already had 5 mm, 8 mm, 25 mm screws, and M3 nuts.) Along with the general usefulness of a large selection of hardware, this greater variety of available lengths will help make it easier to mount accessories to your new Balboa 32U4 balancing robot’s M3-compatible mounting points.

Balboa 32U4 Balancing Robot with 80×10mm wheels and 3D-printed arms.

Balboa 32U4 Balancing Robot with 80×10mm wheels and arms made from LEGO blocks.

Customer Mike McGurrin made this animatronic talking skull that uses Amazon Alexa for interactive voice control. The central part of the project is a Lindberg 3-axis animatronic skull and audio servo controller, which makes the jaw movements follow the audio voice. In this project, the nod, turn, tilt, and eye movements of the skull are controlled by a 12-channel Maestro servo controller running a custom Maestro script that uses one of the channels as an input that is triggered by the Raspberry Pi. The Amazon Alexa integration is handled by AlexaPi.

More details including a parts list and the Maestro Script are available on the project page.

Forum user DrGFreeman has been posting about his custom Mini Sumo robot. He designed the chassis in CAD and 3D printed it; the model is available on Thingiverse. An A-Star 32U4 robot controller reads the QTR-1RC reflectance and Sharp GP2Y0A60SZLF analog distance sensors while powering the motors with its dual onboard motor drivers. DrGFreeman plans to build two copies of the robot: one with 75:1 micro metal gearmotors and one with 50:1 micro metal gearmotors so he can pit them against each other and figure out whether more speed or torque does better. This video shows the behavior he’s programmed so far:

The whole build log along with more pictures and discussion is in the forum post.

At Pololu we maintain around thirty open-source Arduino libraries, and we keep adding new ones whenever we make a new carrier board or Arduino shield. People typically use these libraries with Arduino-compatible boards, such as our A-Star programmable controllers or Arduinos. We also have Arduino libraries for our user-programmable robot kits like the Romi 32U4 robot, Balboa 32U4 robot and Zumo 32U4 robot.

Sometimes we need to make changes to a lot of libraries at once, like when we wanted to add all of our libraries to the Arduino Library Manager. For us, library manager compatibility requires changing the directory layout, but doesn’t require changing the library or example code. With this many libraries to change, there is a risk of potentially breaking a working library by misspelling or moving a file incorrectly. Fortunately, customer Walt Sorensen introduced us to PlatformIO and Travis CI, which let us test compiling Arduino libraries every time they are pushed to GitHub.

Setting this up is easy enough that we encourage you to do it on your Arduino libraries! First, sign up for Travis CI (a testing service, free for open-source projects) and enable it for the GitHub repository you want to test. Now, every time you push new code to your repository, Travis CI will try to see if there is a .travis.yml file in the top level with instructions for running tests.

If your project has the structure of an Arduino Library Manager project and you have at least one example sketch, our short .travis.yml file should work. This file instructs Travis CI to compile the library and its examples against all the supported Arduino boards (specified in the “env” list of the .travis.yml file). The results can be seen on Travis CI’s website (for example, here is Pololu’s Travis CI page). The Arduino compiler is provided by PlatformIO, an open source ecosystem for internet-of-things development, which supports a long list of Arduino-compatible boards.

You can share your Travis CI build status by embedding a badge into your GitHub readme page:

Of course, for most library changes, we still have to test on actual hardware, but now every time we update our libraries (or a contributor submits a pull request), we can be sure they will at least compile on every supported board.

Congratulations to the Bohlebots teams for winning all four open categories of the West German Robocup soccer 2017! Robocup soccer is a competition where two autonomous robots on each side play soccer in a walled arena. We covered them winning multiple times in the past on this blog. Their robots use Pololu 20D mm metal gearmotors and VNH5019 motor driver carriers.

Bohlebots junior team winning West German Robocup 2017 soccer open 1v1.

One of our customers, Jochen Alt, built a robot that balances on top of a ball by driving around on it with omni-wheels. Even better, he very thoroughly documented the project on GitHub! The robot uses a number of parts from Pololu including 37D mm metal gearmotors with encoders, stamped aluminum L-brackets for 37D mm metal gearmotors, and three VNH2SP30 motor driver carriers.

A good overview of the robot and the control system are on his Hackaday project page.

Last week, I wrote about our new distributors in the Americas. We’ve also added three new distributors in Asia and Australia since our last round of new distributor introductions:

ToolParts is an online store in Seoul, South Korea, bringing our total number of distributors in Korea to five! They carry a selection of Pololu products including voltage regulators, motor drivers, and sensors.

Tronixlabs Australia is an online store located near Melbourne. They offer $5 flat rate shipping for all of Australia, and they do same-day shipping (a service we are also proud to offer at Pololu). They join our six other Australian distributors. Visit their Pololu products category to see what they carry.

Fab.to.Lab is an online retailer of hobbyist and prototyping electronics based in Bangalore, India. They sell a variety of Pololu products including robots, sensors, gearmotors, and motor drivers. Pololu now has six distributors in India.

See the full list of over 200 distributors to find one in your area.

A technical paper about hydrofoil design by members of the Cedarville University Solar Boat Team won a $1,000 Honorable Mention in the 2016 Mandles Prize for Hydrofoil Excellence from the International Hydrofoil Society. The boat they’ve been building uses a few Pololu Jrk 12v12 USB motor controllers to drive linear actuators that control the hydrofoil angle of attack which controls the boat’s flight. (Yes, flight: a hydrofoil boat uses wing-like hydrofoils that lift up the hull as they “fly” through the water.) They plan to enter this boat in the “Top Class” of the Dutch Solar Challenge. The “Top Class” provides entrants the opportunity to design every aspect of their solar-powered boat, which they will use in a series of sprint and endurance races over the course of five days. They also plan on racing in the Solar1 Solar Boat World Championship at the Yacht Club de Monaco.

Congratulations to Matthew Siracusa and William Rule who placed first in the Robot Arm competition of the Science Olympiad SE PA Regional Tournament last Wednesday! They used our custom laser cutting service to cut the base and structural components of the robot arm out of black ABS. We wrote about another one of Matthew’s projects on this blog when he made a 6-string banjo (that has a frame we also laser cut) as part of the 2014 Science Olympiad.

The Science Olympiad website has more information about the Robot Arm competition.