Pololu Blog (Page 3)
Welcome to the Pololu Blog, where we provide updates about what we and our customers are doing and thinking about. This blog used to be Pololu president Jan Malášek’s Engage Your Brain blog; you can view just those posts here.
Silicone Tire Pair for 80×10mm/90×10mm (left) and 60×8mm/70×8mm (right) Pololu Wheels.
We have recently had several requests for just the tires from our largest Pololu wheels, so here they are! The silicone tires are available in two sizes, with the smaller tire working with our 60×8mm and 70×8mm wheels and the larger tire working with our 80×10mm and 90×10mm wheels. The tires are intended primarily as replacement parts for our wheels, but they can also be used as nicer tires for other similarly sized wheels, such as the 2-5/8″ plastic wheels for Futaba servos.
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!
We are now carrying a DB15 Screw Terminal Adapter for MCP23X/26X Advanced Motor Controllers. The adapter breaks out connections from the DB15 connector to a set of screw terminals, making accessing those pins easier during prototyping. It is designed specifically to work with the MCP Advanced Motor Controllers that feature a DB15 connector: the MCP233, MCP236, MCP263, and MCP266. However, it could also be used as a generic breakout board for other hardware that uses the same connector, like old computer joysticks or MIDI devices (where it is called a game port).
I am happy to announce the release of our newest regulators, the D36V28Fx family of step-down voltage regulators. These regulators support a wide input voltage range (up to 50 V!) and can deliver up to 4 A, making them well suited for use with power-hungry processors like the Raspberry Pi and projects involving servos or small motors.
Step-Down Voltage Regulator D36V28Fx, assembled on breadboard.
Step-Down Voltage Regulator D36V28Fx, bottom view with dimensions.
The family consists of six fixed output voltage versions between 3.3 V and 12 V:
- D36V28F3: Fixed 3.3V output
- D36V28F5: Fixed 5V output
- D36V28F6: Fixed 6V output
- D36V28F7: Fixed 7.5V output
- D36V28F9: Fixed 9V output
- D36V28F12: Fixed 12V output
And since we make these ourselves here in Las Vegas, we can also quickly make versions with custom output voltages; please contact us us for more information.
Comparison to the D24V22Fx step-down regulator family
The D36V28Fx family now becomes our recommended alternative to the slightly smaller D24V22Fx if you need a little more power or operation above 36 V:
Comparison of the maximum continuous current of Step-Down Voltage Regulators D36V28Fx and D24V22Fx.
The D24V22Fx still outperforms the D36V28Fx when it comes to dropout voltage and quiescent current:
Comparison of the dropout voltage of Step-Down Voltage Regulators D36V28Fx and D24V22Fx.
Comparison of the quiescent current of Step-Down Voltage Regulators D36V28Fx and D24V22Fx.
As usual, we are offering an extra introductory special discount on these new regulators, to help share in our celebration of releasing a new product. The first hundred customers to use coupon code D36V28XINTRO can get up to three units for just $7.77 each!
Next week is National Robotics Week: a week centered on increasing awareness of the robotics industry and the impact that robotics will have on the future. To celebrate, we’re having a sale! All Pololu robot kits and their accessories are 25% off; this includes our 3pi, Zumo, Balboa, and Romi robots. Additionally, all active Pololu-brand items are 20% off, so you can stock up on motor controllers, regulators, sensors and much more! Whether you are a seasoned robot builder or just getting started in robotics, you are sure to find something in this sale for you. Check out the sale page for more information.
We are excited to offer new carriers for Hall effect-based linear current sensors from Broadcom. These easy-to-use bidirectional current sensors are available in three current range options:
- ACHS-7121 Current Sensor Carrier -10A to +10A
- ACHS-7122 Current Sensor Carrier -20A to +20A
- ACHS-7123 Current Sensor Carrier -30A to +30A
The ±10A and ±30A version have the same output sensitivity as our older ±5A and ±30A Allegro ACS714 Hall effect-based linear current sensor, respectively, so they should work as a drop-in replacement in many applications.
As usual, we are offering an extra introductory special discount on the ACHS-712x current sensor carriers, to help share in our celebration of releasing a new product. The first hundred customers to use coupon code ACHSINTRO can get up to five units for just $3 each!
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.
With this new RoboClaw case, our selection of RoboClaw products just got even cooler – literally! In addition to protecting the motor controller, this case also has an integrated fan, which will allow an enclosed RoboClaw to deliver higher continuous currents and sustain peak currents longer. The case works with 2x15A, 2x30A, 2x45A, and ST 2x45A RoboClaw motor controllers and features cutouts for accessing the motor outputs and the various control input header pins.
We have updated our A-Star 32U4 Prime LV with a new regulator that offers a wider operating voltage range and increased current capabilities. For those of you not already familiar with our A-Star 32U4 Primes, they are a series of ATmega32U4-based, USB-programmable controllers with integrated regulators that offer operating voltage ranges not available on typical Arduino-compatible products; this new “LV” variant features an improved buck-boost converter that enables efficient operation from 2 V to 16 V power supplies (Note: it requires an input voltage of at least 3 V to start, but it can operate down to 2 V after startup). The A-Star Primes are arranged in the common Arduino form factor exemplified by the Uno R3 and the Leonardo, so they are compatible with many Arduino shields, including all of the Arduino shields we carry.
In addition to the increased input voltage range for the new A-Star Prime LV, the new regulator also provides more current. The graph below shows the current available on the new LV (ac03e) in blue compared to the old LV (ac03b) in purple. It is important to note that to use the full current available on the new A-Star Prime LV, you must connect to the VREG pin on the board and not the 5V ouput pin. The 5V output pin is limited to about 1.9 A because of the TPS2113A power multiplexer that makes up the board’s power selection circuit (a feature that sets the A-Star Primes apart from competing products). The power multiplexer decides whether the board’s 5 V supply is sourced from USB or an external supply via the regulator, allowing both sources to be connected at the same time and enabling the A-Star to safely and seamlessly transition between them. The multiplexer is configured to select external power unless the regulator output falls below about 4.5 V. If this happens, it will select the higher of the two sources, which will typically be the USB 5 V bus voltage if the A-Star is connected to USB. More information about the multiplexer can be found in this section of the A-Star 32U4 user’s guide under the Power heading.
The original version of the A-Star Prime LV, which operates from 2.7 V to 11.8 V, is now on clearance for 40% off! If you don’t need the increased output current and wider voltage range the new board offers, the previous version is still a great programmable controller to consider. Both the new and original A-Star Prime LVs come in multiple configurations. The complete selection of both versions can be found in the related products list below.
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!