Pololu Blog (Page 31)
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.
If you read Grant’s Creepy eyes Halloween prop post, then you already know that several of us here at Pololu are working on Halloween projects. I based my project on a motion tracking Halloween prop tutorial by Jason Poel Smith that I saw last year on the Make magazine website. The concept is simple: make a Halloween prop mysteriously follow an unsuspecting person as they walk by. The tutorial by Jason Smith uses photoresistors to track a person by detecting their shadow and moving a servo with a Halloween prop attached to it. This works well, but there are a few things that I thought could be improved. Continued…
Halloween is just a few short weeks away, and that means it’s time to start making an awesome costume or building an extravagant yard display (unless you’ve already been hard at work on one for months). Whether you want to dress up or decorate your home, we offer lots of products that can make your projects stand out, so we’re having a Halloween sale to help you get the parts you need!
From now until October 22, you can get 10% off hundreds of products, from servos and LEDs to sensors and programmable controllers. Even bigger discounts of up to 30% are available on a few select items. See the sale page for more details and the full list of products.
As always, we would love to hear about anything cool you make with our stuff, so please share it with us via email or on our forum; we might feature it on the blog! This month, we’ll be posting a series of Halloween-themed projects of our own to help inspire you.
Remember the post I wrote two weeks ago about our tiny D24V25F5 voltage regulator and some of the testing that we did on it? Well, we were so happy with how that regulator turned out that we decided to make a higher-power version with a larger inductor and beefier MOSFETs. This new regulator is the D24V50F5, and while it is only 0.1″ bigger than its 2.5 A cousin, it can deliver 5 amps!
Side-by-side comparison of the 2.5A D24V25Fx (left) and 5A D24V50Fx (right) step-down voltage regulators.
You can see the bigger MOSFETs on the bottom side:
Comparison of the D24V25Fx (left) and D24V50Fx voltage regulators showing larger MOSFETs on the higher-power board.
The D24V50F5 can also take inputs up to 38V and has typical efficiencies of 85% to 95%. It’s amazing how much power these little 3×3 mm MOSFETs can handle, and with its compact size and high power, this regulator is our new favorite.
In the lead up to Halloween, I thought it would be fun to make some Halloween-themed props; in particular, I was interested in making something creepy. What first came to my mind was one of those creepy portraits with moving eyes. To change it up a little, I decided to use a mask instead of a picture (which I thought would make it easier to hide the electronics). Down at a local store called Halloween City I picked up a cheap mask and some plastic eyeballs (though a more crafty person might just make their own mask and eyeballs). I made sure the mask was a bit stiff because I needed it to hold shape without actually having someone’s face in it. For the electronics in the project, I grabbed two sub-micro servos, a Micro Maestro, and a 4.8V battery pack. If you don’t have jumper wires it might also be helpful to get a pack of those, but this build only uses one to jump battery power to the Maestro’s logic power. Continued…
The 2pi, built by Mark Moran, is a line following robot based on our 3pi robot. The 2pi uses our 100:1 micro metal gearmotors, motor brackets, 32mm wheels, 1/2″ ball caster, QTR-8RC reflectance sensor array, and U3V12F9 switching step-up voltage regulator. All those components are mounted to a chassis that was cut from PVC foam.
The robot uses a custom made PCB with an ATmega328 as the brain (the same AVR chip used in the Arduino Uno, some of our Orangutan Robot Controllers, and, of course, the 3pi). You can see the 2pi following a line in the video below.
For more information about how Mark built his robot, check out his Instructables guide.
Everyone wants encoders on their motors. If you think you don’t, you just don’t know it yet. I think the main reason is that we really just want motors to do what we tell them to do, but they don’t. One of the most common beginner questions we get is some variation of, “why doesn’t my robot go straight?” or “I got two of the same motor but they do not go the same speed; is something wrong with one of them?” More seasoned robot builders know that since there will always be variations in everything that contributes to a motor’s performance, our best hope is to put a sensor on the motor to monitor what is actually happening and then adjust the motor control to make reality better match our desires. Continued…
Get FREE copies of Circuit Cellar magazine’s September issue and Elektor magazine’s September issue with your order, while supplies last. To get your free issues, enter the coupon codes CIRCUIT0914 and ELEKTOR0914 into your shopping cart. The Circuit Cellar magazine will add 6 ounces and the Elektor magazine will add 7 ounces to the package weight when calculating your shipping options.
We recently substantially reduced prices on our stepper motor driver carriers, and I figured this announcement was a good time to give you an update on our perspective and capabilities.
It has been over five years since I designed our original stepper motor driver carrier, which was for the A4983 from Allegro. While fairly straightforward, the implementation reflected several design philosophies that go into Pololu products, such as making the boards as small as practical and including the right extra components to make the main chip easily usable without unnecessarily limiting its features. Continued…
Last December we started carrying addressable RGB LED strips based on the WS2812B LED driver. Since that driver integrates an LED and a driver into the same package, we were able to offer higher density strips than before.
We are excited to announce that we are now carrying an even higher-density WS2812B LED strip. This strip has 72 LEDs and is 0.5 m long, for a density of 144 LEDs per meter. It is also the shortest WS2812B strip we carry.
LED side of the WS2812B-based addressable LED strips, showing 30 LEDs/m (top), 60 LEDs/m (middle), and 144 LEDs/m (bottom).
A 1/2-meter, 72 LED addressable RGB LED strip on the included reel.
This LED strip, like the other WS2812B strips we carry, has both input and output JST SM connectors, which make it easy to connect multiple strips together. It is compatible with many popular microcontrollers, and we provide Arduino libraries to help you get started. More information about this LED strip, including how to use it, can be found on its product page.
You can also view our entire selection of WS2812B LED strips.