Pololu Blog (Page 57)
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.
We’re now selling an I²C long distance differential extender from SJTbits. When you connect one of these boards to each I²C device in your system, they transparently convert all I²C communications to differential signaling and back, allowing the range of your I²C bus to be significantly increased (they have been tested at ranges of over a hundred feet).
For more information, see the I²C Long Distance Differential Extender product page.
Erich, a professor at the Lucerne University of Applied Sciences and Arts in Switzerland, posted to our forum about their first Mini Sumo tournament, which took place this past weekend. The tournament was a part of Erich’s embedded systems programming class, for which he created a custom Mini Sumo robot platform for his students to modify. His robots use a custom PCB that mounts to the Zumo chassis kit and connects to the reflectance sensor array. Instead of an Arduino, his PCB uses a Freescale FRDM-KL25Z as the microcontroller board. Students customized the modified Zumos with their own sensors (we saw at least a few of them using our IR proximity sensors). 21 robots were entered into the competition, and a winner was determined over 5 rounds. Links to a competitor showcase video, several battle videos, and more information about the competition can be found in his forum post.
We are also excited to see a list of performance tweaks that Erich created for Zumo robots to be more competitive in Mini Sumo. We have made this available as a resource on the Zumo product pages.
While he was experimenting with our Zumo chassis, Erich posted to our forums a few times updating us on the progress of his modifications. You can follow his robot’s progression by visiting these forum posts:
March 2013: Zumo Robot with FRDM-KL25Z Board
September 2013: Zumo Robot with Pololu Plug-in Modules
October 2013: Zumo Robot with Pololu Plug-in Modules, assembled
We saw this robotic ping-pong ball collector by Will Jessop on the Raspberry Pi blog a few days ago. The robot uses the Pololu 30T Track Set, a Raspberry Pi, and a lot of custom electrical and 3d-printed mechanical parts.
Apparently, Will plans to put his robot into service at the office of his employer, 37signals. This is exciting for us at Pololu because 37signals is the originator and a major sponsor of the Ruby on Rails web framework, on which our website is built. And although we did not attend this year’s RubyConf, we are proud that some of our parts, as shown in the video above, made an appearance.
You can find detailed build information in Will’s ping-pong robot blog posts.
Do you want your project to vibrate annoyingly like a cell phone? Then our new vibration motor might be just what you are looking for. The vibration motor is intended for 3 V operation and is small (11.6 × 4.6 × 4.8 mm) and light (0.8 g), which means you do not need a lot of space in your project for it. The vibration motor includes the small rubber sleeve shown in the picture, which allows for easier mounting and slightly dampens any chattering that might occur against the surface it is mounted to.
For more information, see the Vibration motor 11.6 × 4.6 × 4.8 mm product page.We also carry three shaftless vibration motors:
Using our Custom Laser Cutting Service, you can design and cut your own Christmas ornaments. Whether this is to decorate your own tree (and show off to family and friends visiting), or to give away as gifts — personalized decorations are always a big hit for the holidays! We cut the following Pololu Christmas ornaments out of 1/8″ sapphire blue mirrored acrylic with a raster-engraved image, creating a reflective scene on a translucent background.
Let’s face it, we’re all a bit too familiar with last-minute Christmas shopping, and it’s not too late to order and have these in-hand by the holiday (though we’re getting close, so expedited service or shipping might be required)! The set of seven ornaments like the ones shown can be cut for our low minimum order charge of $25. Of course, since each person’s design will vary a bit, the exact price and quantity might vary. See our Custom Laser Cutting Guide for more information about how our laser cutting service works, or submit a quote request now to get started!
Merry Christmas! We got some new LED strips in a week or so ago that are based on the WS2812B. I was pretty excited to play around with them, so I decided I would decorate Ben’s house and make him film this video with me. (I know. I should have decorated my own house, but I live far from the office… and don’t have a wife.)
We should have the code we used for the LEDs available on our github page in a couple of days.
Ever since the release of our original adjustable boost regulators, customers have been requesting higher-power versions. Doing power systems right is not easy, and minute differences in component choices and layout can make a huge difference in performance: we went through three different failed designs before arriving at our new U3V50x family of step-up voltage regulators, which we think offers a great balance of size, performance, and price.
These new boost regulators can generate up to 30 V from input voltages as low as 2.9 V while allowing for input currents as high as 5 A and offering typical efficiencies of 80% to 95%, making these our most powerful boost regulators. The regulators include built-in reverse-voltage protection, over-current protection, thermal shutdown, and an under-voltage lockout that keeps the modules from behaving erratically when the input voltage gets too low. The U3V50x family includes versions with fixed 5 V, 6 V, 9 V, 12 V, or 24 V outputs and versions with adjustable 4 V to 12 V or 9 V to 30 V outputs.
The compact boards (0.6″ × 1.9″) have two mounting holes and can be assembled with the included 5mm-pitch terminal blocks or 0.1″ header pins.
If you’re looking for an inexpensive motor driver that works with higher voltages, but our DRV8801 carrier’s single channel isn’t enough, we now offer another option: a carrier board featuring Allegro’s A4990 dual motor driver.
The A4990 can deliver a continuous current of up to 0.7 A per channel at voltages from 6 to 32 V, making it a good choice for small, low-current motors that run on relatively high voltages. Onboard sense resistors enable the A4990 to actively limit the peak motor current to about 0.9 A per channel, and the carrier board adds a reverse-voltage protection circuit in addition to the robust IC’s built-in protection against under-voltage, over-voltage, over-temperature, and short circuits.
For more information, see the A4990 carrier product page.
This week we started selling new addressable RGB LED strips. These LED strips are a great way to add some color to a project, and I would like to show a little bit about how they work. Here is a close up showing one segment of a new LED strip:
Close up of one segment of a WS2812B-based LED strip, with the red, green, and blue LEDs on at their dimmest setting.
At first glance, it is easy to see the RGB LED and a capacitor, but where are all the other components, such as the LED driver? Well, let’s look more closely at the LED:
Close up of a WS2812B, with the red, green, and blue LEDs on at their dimmest setting.
The LED actually has a driver built into it, which is the large brown rectangle in the picture. This driver receives high-speed color data, storing the first 24 bits it sees and passing the rest of the bits down the strip to the next LED. The driver is connected with tiny wires to the red, green, and blue LEDs. For the photos above, we turned each of the LEDs on at its dimmest setting so you can see their colors. This integrated circuit (IC) consisting of an RGB LED and a driver is called the WS2812B.
Since the WS2812B integrates an LED and a driver into the same package, we are able to offer higher density strips than before. We offer these WS2812B LED strips that have 60 LEDs per meter:
We also offer these WS2812B LED strips that have 30 LEDs per meter:
All of our example code has been updated to fully support the new strips. We provide example code for the Arduino, AVR, and mbed microcontroller platforms. More information about the LED strips and how to use them can be found on the LED strip product page.
Controlling an addressable RGB LED strip with an Arduino and powering it from a 5V wall power adapter.
Are you having trouble mounting things to 1/4″ motor shafts? These new versions of our universal mounting hubs fit most 1/4″ shafts, including round and “D” shafts. Similar to our existing universal mounting hubs for 6 mm shafts, these hubs are sold in packs of two and come with two set screws each (4 total) and the appropriate Allen wrench. These new hubs are compatible with our NEMA 23 stepper motors and come in two different versions: the Universal Aluminum Mounting Hub for 1/4″ shaft, with #4-40 mounting holes or the Universal Aluminum Mounting Hub for 1/4″ shaft, with M3 mounting holes.