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Tito-Stretch: a Pi Wars robot by Hitchin Hackspace

Posted by Jon on 4 June 2019

For the second year in a row, Team Hitchin Hackspace and their robot, Tito-Stretch, placed 4th overall in the Pi Wars! They did this at the Advanced/Pro level, which is Pi Wars’ most challenging competition category. (In case you haven’t heard already: Pi Wars is an international robotics competition that focuses on Raspberry Pi-controlled robots.) The video above features Tito-stretch high-tailing it through the obstacle course event. The team’s speedy performance allowed them to climb to the very top of their division, which is a step above their 2nd place finish in 2018’s obstacle course event.

Tito-Stretch is the latest iteration of the hackspace’s competition robot, which has evolved in name and form over the last few years. As we understand it, the team named the original version of their robot Twenty Two Over Seven (22/7 is one way to approximate pi), abbreviated that to TTOS, and then affectionately transitioned to calling the robot “Tito”. Later, the team lengthened their robot and accordingly appended “-⁠Stretch” to the name.

The designers/builders of Tito-Stretch: Pi Wars team Hitchin Hackspace.

Tito-Stretch on a desk.

Tito-Stretch on gravel.

The Tito-Stretch chassis is a 3D-printed design that uses a pair of skateboard bearings in a way that decouples the front and rear parts of the chassis, allowing each part to roll independent of the other. This passive articulation allows the robot to more consistently maintain all four wheels as solid points of contact on uneven terrain. When assembled, the chassis parts clamp down onto four 12V 25D mm gearmotors, and a VNH5019 motor driver controls each motor. A 5V regulator steps down the voltage of a 3S LiPo and powers a Raspberry Pi 3 Model A+, which is the brain of the operation. The team can remotely control their robot with Bluetooth controllers (they currently use a PS4 controller, but have used other devices in the past), and various accessories like a few VL53L0X time of flight distance sensors help enable autonomous navigation. You can find code for Tito-Stretch, and older versions of Hitchin Hackspace’s Pi Wars robots, on their GitHub page.

Great job on your competition this year, Hitchin Hackspace! We hope to hear more about your robots in the future!

Laser-cut teapot coasters

Posted by Claire on 24 April 2019

This past weekend my mom hosted a tea-themed baby shower for me, and after looking around and not finding any party favors I liked, I decided to make my own custom laser-cut teapot-shaped coasters for it. To get started, I searched some free vector file sites for a vector file of a teapot that I liked and could easily prepare for laser-cutting with CorelDRAW. I chose this one designed by Freepik. Once loaded into the software, I resized the teapot and added text. I personally really like cork as a coaster material since it keeps the cup from slipping and absorbs moisture well, so I also picked up some 1/8″ cork place mats from IKEA.

Evidently, cork is not a material we are asked to laser-engrave very often, so I had to do some experimenting with the engraving settings before cutting out prototypes.

I generally liked the look of the first draft, but realized that at 4 inches total width it was too small to be practical (and readable). In addition, the handle of the teapot was fairly fragile since the cork was only an eighth of an inch thick. Below you can see the first draft of the cork teapot in the upper left. It is missing the small circular embellishment at the base of the handle.

Comparison of different test coaster sizes.

For the second draft, I increased the size to about 5.5 inches, edited my file to thicken the areas of the teapot where the handle connects to the base, and started playing with different acrylic backings to make the coasters more durable and colorful. I tried a version with an outline around the cork teapot and one that fit directly beneath the cork.

In the end, I went with the sleeker acrylic with no outline, though most of the others I consulted here preferred the mirrored outline shown on the left above (despite my insistence that it looked like a magic lamp). I cut out a variety of colors and glued them to the back of the cork with rubber cement.

All in all I think they came out well (though I could have made the attachment for the small circle at the bottom of the handle even thicker), and they were definitely a big hit at the party!

If you want to try your own laser cutting project, submit a quote request here!

Kinetic art installation using 24 Maestros to control 576 servos

Posted by Jon on 2 April 2019

This wall-mounted kinetic art installation by Alain Haerri redirects light from 576 independently actuated square panels. A flattened segment of an aluminum can, cut to the same square shape as the panel, decorates each actuator, and a small servo allows the decorated panel to pivot up or down. The servo’s positioning of the panel can alter how much light is reflected, effectively making that individual panel appear lighter or darker. Taken together, the array of panels produces an image with enough resolution and speed for delightful and mesmerizing visuals.

At the heart of the operation is an Arduino Mega, which, with the help of our Maestro Arduino library, communicates with 24 Mini Maestros (with 24 channels each) to orchestrate the movement of servos. The Mini Maestros are wired together and connected to a single software serial port on the Mega, which controls all the Maestros using the Pololu protocol at 200 kilobaud. Additionally, the installation has a built-in camera, which allows it to do things like mirror the movement of people standing in front of it, as this video shows:

You can find a write-up of Alain’s project on the Arduino Project Hub, where he also shares his code, a complete parts list, and a couple more videos of the table in motion.

Video of Caesar, the first-place rover of the 2019 Indian Rover Challenge

Posted by Jon on 8 March 2019

The first-place winner of the 2019 Indian Rover Challenge, Team Anveshak from IIT Madras, sent us a link that shows their rover in action! The video is their submission to the 2019 University Rover Challenge (URC) System Acceptance Review (SAR), which is a major qualification round for participating in the URC finals. Good luck with SAR qualifications, Team Anveshak!

We first blogged about Team Anveshak’s rover back in January. For more information on the rover and the competition, including pictures, check out that post!

Bigger 3D printed buttons for the Zumo 32U4

Posted by Brandon on 6 February 2019

Mount Holyoke College professor Peter Klemperer designed a custom add-on for the Zumo 32U4 to give easier access to the user pushbuttons. Peter made the bigger buttons as a response to some of the students in his classes finding it difficult to use the small onboard pushbuttons.

The design even has small cutouts so you can still see the indicator LEDs. To add the adapter plate to the Zumo chassis, you can use two #2 screws and nuts (7/16 inch length screws worked great for me). The easy-to-print STL files along with the Fusion 360 files are available on Peter’s GitHub repository for the project, and you can find more information on Peter’s blog post on his website.

If you print your own bigger buttons for your Zumo 32U4 be sure to let him (and us!) know; we would love to see some pictures! Here’s a shot of the one I printed out for my personal Zumo 32U4:

Macro photography using Tic stepper motor controllers

Posted by Jon on 4 February 2019

Mike’s portable stack & stitch image acquisition setup, which includes three Tic T500s.

Mike’s precision stack & stitch image acquisition setup, which includes three Tic T500s.

Forum member Mike is using our Tic stepper motor controllers in his automated stack & stitch image acquisition systems, which he has been using to get extremely high resolution images of various integrated circuits. Each system uses linear rails and stepper motors to properly align the camera/lens and the object to be photographed. Two stepper motors position the subject and a third adjusts how close the camera is to the subject. A Tic T500 controls each stepper motor and each Tic connects to a USB port on a Raspberry Pi 3B or Raspberry Pi 3B+, which acts as the main computer. Afterward, Mike stacks the images with Zerene Stacker and stitches them together with Photoshop. Some of his image sessions capture as many as 6000 individual images that are used to produce a single 300 megapixel image!

Zooming in on a stack & stitch test image.

A close-up view of a stack & stitch test image.

You can find more information about Mike’s stack & stitch image acquisition systems (like what specific mechanical hardware he is using) in this forum post. Also, to see and/or download a set of high resolution pictures taken with those setups, follow this link.

Rover team from IIT Madras places first in Indian Rover Challenge

Posted by Jon on 29 January 2019

Congratulations to Team Anveshak from IIT Madras, who took first place at the 2019 Indian Rover Challenge! The IRC is a robotics and space exploration-based competition for college students. Participating teams design and build a Martian rover prototype and use that rover to compete in various tasks like obtaining soil samples, operating electrical racks, and picking up and delivering objects.

Team Anveshak’s winning rover, Caesar, uses 10 different Pololu products! We are especially excited to hear that their rover prominently features our newer G2 High-Power Motor Driver 24v13 and TB9051FTG motor drivers, using 9 of each of those boards.

We love seeing all the awesome things like this that people are doing with our products! For a more complete list of the Pololu parts used in Caesar, check out the related products listed below. If you want to learn more about the team, check out their website.

8 March 2019 Update: See a video of Caesar in action here.

Balboa controlled via cell phone over Bluetooth

Posted by Jon on 4 January 2019

Drew Wilkerson added a Robotis BT-410 Bluetooth-to-serial board to his Balboa Robot, which allows him to control that Balboa from a cell phone. You can watch the video above to see the Balboa being driven around as it balances. More information about this project, including the code running on Drew’s Balboa, can be found in his post on our forum.

Creepy eyes Halloween prop upgrade

Posted by Grant on 22 October 2018

There are only a couple days left in our Halloween sale! Visit the sale page for more information, and if you are in need of some inspiration, check out our Halloween-tagged blog posts for some sample projects, including this upgrade to my creepy eyes prop:

I finally got around to upgrading my creepy eyes Halloween prop. As shown above, I mounted the mask on a picture frame to make it more presentable. I also added some of our VL53L0X time-of-flight distance sensor carriers so that the eyes could follow people in front of the mask. I camouflaged the sensors behind the black layer of foam behind the mask. Below is an image showing how the sensors were hidden in the lower corners of the picture frame:

I also swapped the Maestro out for an A-Star 32U4 micro, so I could communicate with the sensors through I²C. Due to switching to the A-star micro, I added one of our small solderless breadboards to help distribute power and a servo Y splitter cable since both sub-micro servos can use the same signal. I also added a power switch and used some of our premium jumper wires to make connections. You can see all the electronics taped to the back of the picture frame in the picture below.

RC crawling skeleton

Posted by Grant on 19 October 2018

Our Halloween sale is still going strong! Visit the sale page for more information, and if you are in need of some inspiration, check out our Halloween-tagged blog posts for some sample projects, like this simple RC crawling skeleton that I made:

The setup for this project is pretty straightforward: a hobby RC transmitter sends signals through its receiver to a pair of Simple Motor Controllers, which each control a 37D mm gearmotor. The motors mount to a wooden base with a pair of L-brackets and connect to skeleton arms via universal aluminum mounting hubs and a short length of aluminum plating. The offset created by the aluminum plating causes the skeleton to move in a way that makes it look like it is slowly inching towards its next victim!

A 3S LiPo provides power to the system through a pair of XT60 connectors, and the RC connections are made through some spliced female-female premium jumper wires. A black T-shirt covers up the electronics and a pair of cardboard “shoulder pads” help ensure the tee does not get tangled up in the rotation of the arm-bones.

In practice, the crawling skeleton is more amusing than scary: it crawls really slowly and the sound of the motors turning is too industrial/mechanical to haunt anyone’s dreams. The sound is, however, loud enough to startle any unsuspecting friends!

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