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

Chicago Electronic Distributors are a new distributor in—you guessed it— Chicago, USA. They offer a variety of Pololu products for sale on their website and free shipping on US orders over $100. They prefer customers buy directly from their website, but they also have an eBay and Amazon store.

FlexRC is an online store in Canada that specializes in multi-rotor drones. They sell a couple of our voltage regulators alone and as part of kits. Search “pololu” on their website to see all their products with Pololu regulators. They have over 50 quadcopter videos on their YouTube channel.

ElectroStore joins our five other distributors in Ecuador. They are based in Quito and Riobamba, but they ship all over the country. Their product selection is available on their Facebook page, and you can contact them to place an order, or you can order through MercadoLibre Ecuador.

Smart Electronics Projects is an online electronics store in Lima, Peru. They sell a variety of Pololu products including motors drivers, encoders, gearmotors, and wheels. They also offer courses in robotic and electronics design, and provide 3D printing, laser cutting, and design services.

CPIDI Vava – Technologies is an online store also in Lima, Peru, bringing the total number of distributors in Peru to three! They carry a selection of Pololu metal gearmotors, wheels, and other products you can see in their Pololu category.

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

This animated C-3PO replica, made by one of our customers, moves its eyes, arms, head, and—in true C-3PO fashion—tells tasteless jokes. The movements are animated by a Pololu Mini Maestro 18-channel USB servo controller. A Pololu RC switch with relay (controlled by the Maestro, not an RC transmitter) shuts off the power to the head to avoid servo humming noises. (You can achieve a similar result with most servos by not sending RC servo pulses, which a Maestro does when the servo target is zero.)

The customer’s C-3PO web page has more videos and extensive documentation on how the replica was built.

One of our customers, “Bartman” on the dronevibes.com forum, has made a video of himself planning his build and a forum post that explains how he built his quadcopter. He was inspired by the DJI Inspire 1, which raises its struts to get them out of the camera’s way. Bartman proposes a lighter and cheaper arrangement: when flying the quadcopter in its semi-autopilot “carefree” mode, he switches yaw control from the pilot to the camera operator. This gives the camera operator panning (via the entire copter’s yaw motion) without the need for a separate panning mechanism. He uses a Pololu RC multiplexer to achieve the control switching.

A close-up of the RC mux on Bartman’s multi-rotor.

More details and discussion are in the forum thread.

It only took two years but finally the automatic monitor is PERFECT pic.twitter.com/NTG5CiShqT

— Raph Koster (@raphkoster) February 19, 2017

Customer Raph Koster made this slick automatic rotating arcade cabinet display, which allows the arcade cabinet to easily switch from landscape to portrait depending on the game. The monitor is rotated by a servo controlled by a Micro Maestro 6-Channel USB Servo Controller. The Maestro is especially convenient for this type of project, because you can connect it to the computer using USB then control the servo using our command line utility usccmd.

Raph shares his usccmd scripts for automating the rotation along with a full parts list and extensive step-by-step build information in his forum post at ArcadeControls.com.

I am happy to bring some overdue attention to our customer who created TwoPotatoe, a balancing robot that I first wrote about on this blog a few years ago. This past fall, TwoPotatoe and his new robot ThreePotatoe competed in the Sparkfun AVC Competition. TwoPotatoe won first place for the 10 lb to 25 lb weight class. Check out the AVC video below! TwoPotatoe starts its run at about 53:00. ThreePotatoe won second place in the 25 lb to 40 lb weight class. Considering all the weight classes together, TwoPotatoe and ThreePotatoe scored third and fourth place overall, which is very impressive considering they were competing against four-wheeled robots that didn’t have to balance. ThreePotatoe’s run starts at about 1:08:30.

You can find more pictures and information about TwoPotatoe and ThreePotatoe in the AVC competition on the TwoPotatoe website.

Customer Guido Bonelli Jr., who is also the creator of the Dr.Duino Arduino shield, had us laser cut pieces of baltic birch for a unique piece of furniture for his home: a large, interactive puzzle. An Arduino Mega 2560 R3 controls the various puzzles and contraptions packed into this piece. His article in Design News goes into more detail including a parts list and more pictures.

We’ve added a bunch of new distributors since we last did new distributor introductions, and we are excited to welcome these new European distributors in order from east to west:

Melopero S.r.l.s., an online electronics store in Rome, Italy, joins our eight other Italian distributors. They offer flat rates for shipping to Italy and rest of Europe and free shipping on orders over €85. Check out their Pololu category to see what they carry.

Diigiit Robotics has been a Canadian distributor of Pololu products for a few years, and they recently opened Diigiit Robotics Europe in Paris, France to serve Europe. Diigiit ships everywhere in Europe and carries almost 200 different Pololu products.

A4 Technologie is an online store for education professionals in Les Ulis, a suburb of Paris, France. They sell a wide array of products, including electronics, science equipment, materials, art kits, and educational kits. Search "POL" to see some of the Pololu products they carry.

These two bring the total distributors in France to 14!

DigitalMeans Ltd is an online store in London, UK, that focuses on Arduino and DIY electronics parts. They carry products from SparkFun, Adafruit, SeedStudio, and now Pololu. They offer free UK shipping for orders over £50.

Fábrica Digital is an online store in Jerez de la Frontera, Cádiz, Spain. They specialize in 3D printing, and that’s why they are excited to carry our stepper motor drivers, which are popular in many RepRap 3D printer designs (The P in RAMPS is Pololu!). You can see all the Pololu products they carry and read their blog post (in Spanish) announcing them becoming a Pololu distributor.

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

One of our customers posted about his balancing robot on our forum. A Raspberry Pi Model B is the central controller for the robot. It communicates with a RoboClaw motor controller for motor control and measures the angle and angular velocity with a MinIMU v2. The RoboClaw also decodes quadrature encoder signals for measurements of position and velocity. The drivetrain is made entirely of Pololu parts: 37D metal gearmotors with encoders, brackets, mounting hubs, and wheels.

The robot’s control algorithm allows it to correct for both positional and angular disturbances, and it can be controlled wirelessly. To develop the control system, this robot builder measured the step response of the motors using the encoders.

For more details about how the control system was developed, see the forum post.

Pololu forum user Martin_H posted about his robot that plays the Tower of Hanoi with paper blocks. An RP5 chassis drives along a track, locating itself with electrical tape seen by QTR sensors. It serves as the base for a custom robot arm made from U-channel and driven by servos. The robot is controlled by a Baby Orangutan B-328 Robot Controller.

The forum post has a parts list and more details.

One of our customers motorized his crank-powered adjustable-height desk by using a brushed DC motor to drive a chain that turns the crank. He details the project in this blog post. He described the project as a “learning experience”. He started with a Pololu Simple Motor Controller 18v7, which unfortunately did not survive a stall when driving an 18 V drill motor. Some drivers survive over-current situations better than others, but our general recommendation is to choose a motor driver with a continuous current rating above the stall current of your motor.

Cordless drill motors—which typically don’t come with a datasheet—can easily draw tens of amps when stalled. Note that the “peak” current rating is not usually relevant, since a driver might only be able to withstand that current for a few milliseconds. Also, you need to be especially careful when operating at high voltages: an 18 V battery can easily generate spikes above the 40 V limit of this driver if connections are made or broken while the system is powered.

After some technical support from Brandon, he switched to the beefier Pololu Simple High-Power Motor Controller 24v12 (and a lower-current motor with a datasheet, and a current-limiting power supply) to control the motor connected to his drive mechanism made from Actobotics parts. The Simple Motor Controller’s support for limit switches also came in handy for cutting off the motors when the desk reached the maximum or minimum height. He also added some LEDs for under-desk lighting.

After the electronics and mechanisms were all working, he used the Pololu USB Software Development Kit to create a C# desktop application that controls the Simple Motor Controller over USB.

The build log along with more pictures and videos is in this blog post.