Pololu Blog (Page 25)
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 have updated our Programming Orangutans and the 3pi Robot from the Arduino Environment document to support version 1.6.0 of the Arduino IDE, which is the latest stable version. Thanks to improvements in the Arduino IDE, we were able to make the instructions for getting started much easier.
The Orangutan line of AVR-based robot controllers started ten years ago and has since expanded to include boards with a variety of AVR processors and on-board peripherals, from the minimal Baby Orangutan B-328 to the powerful Orangutan SVP-1284 and X2. Many of the Orangutans share handy features like a buzzer, LCD, and buttons, but the integrated dual motor drivers found on every Orangutan are what justify calling it a “robot controller”. Our 3pi robot is an extension of Orangutan concept to a complete robot, so we think of the 3pi as pretty much part of the Orangutan family.
(Don’t need integrated motor drivers? Check out our Arduino-compatible A-Star family of microcontroller boards.)
Pololu 3pi robot.
The Orangutan SV-328, Baby Orangutan B-328, and 3pi all use the same AVR ATmega328P processor as the Arduino Uno, so it is natural to want to program them from the Arduino environment. However, there are a couple of key differences to overcome. First, the boards have no pre-installed Arduino bootloader or built-in USB-to-serial adapter. This simplifies the design and frees up some resources for your application, but it means you have to program them with an external programmer like the Pololu USB AVR Programmer. Also, the clock on these boards runs at 20 MHz, while the official Arduinos are at 16 MHz, so time-sensitive code might not be compatible.
Adding support for the Orangutans and programmer to the Arduino IDE used to involve manually editing a few configuration files with a text editor. With this latest update, you can simply copy a folder into your Arduino sketchbook directory.
Another notable Arduino change is improved support for AVRs running at different speeds. Functions such as
pulseIn now adapt to the clock frequency specified by the
F_CPU macro and should work fine on an Orangutan running at 20 MHz.
To get started, see our guide.
The SparkFun Inventor’s Kit has everything you need to construct a variety of circuits that will teach you how to use an Arduino to read sensors, display information on an LCD, drive motors, and more. No previous programming or electronics experience is necessary, which makes this a great way for beginners to get started with embedded systems.
For more information, see the product page.
Engage your brain as well as your heart this Valentine’s Day by picking up some of our perfectly matched pairs of products at a sweet discount. From Friday through Sunday we will have more than 100 items on sale at up to 20% off. You can find all the deals on our Valentine’s 3-Day Sale page.
Jonathan Spitz made a fun robot he calls Charlie, the cricket. In his LinkedIn post, Jonathan explains that Charlie uses four motors. Two of the motors are used for walking and the other two are used for sprawling. The four motors are controlled by two Baby Orangutans, which also handle the closed-loop feedback from encoders to free up processing on the Arduino Micro.
The insides of Jonathan Spitz’s Charlie, the cricket.
Charlie’s novel propulsion system of spinning legs that can be tilted was inspired by one of Jonathan’s colleagues. They allow Charlie to traverse difficult terrain as shown in this video:
Charlie is a follow-up design on an earlier robot Jonathan made named Billy, the blue beetle, which was larger and lacked the ability to sprawl. Charlie also was designed to have the ability to drive on its back, which is something Billy could not do. You can read about Jonathan Spitz’s experiences with Billy in his LinkedIn post.
This blog post is about some personal difficulty I’m going through: last month, my baby died unexpectedly a day or two before he was born. I could just collect my thoughts in my private journal, but I am sharing my experience here on the Pololu blog because most of the people I interact with and care about are related to Pololu, be they friends, employees, vendors, or customers. Just about everyone at Pololu knew of my eager anticipation of this new baby, and any visitors were aware that I might miss our meetings with short notice depending on when the baby arrived. Continued…
Thomas Schoch, who previously built the PiBot-B we blogged about, built another robot with a Raspberry Pi. His robot, the PiBot-A, uses our DRV8835 Dual Motor Driver Kit for Raspberry Pi B+ with a Raspberry Pi Model A+ to control two 100:1 Micro Metal Gearmotors. The robot also uses our S7V7F5 Switching Step-Up/Step-Down Regulator to supply the Raspberry Pi with 5 V from the motor power supply, allowing the whole robot to be powered form a single source.
The PiBot-A is controlled by a Web-App from Thomas’s iPhone. It communicates over WiFi to the Raspberry Pi, which is running lighttpd and PHP. The Python program on the PiBot-A uses the WiringPi library to send signals to the motor driver kit to drive two 100:1 Micro Metal Gearmotors that are connected to the chassis with our Micro Metal Gearmotor Brackets. Thomas also added an array of Sharp digital distance sensors to give the robot obstacle detection. You can find a video of the PiBot-A avoiding boxes below:
For a complete write-up of the robot, check out the PiBot-A page. It is written in German, but it has a link at the top to translate it into English using Google Translate.
11 February 2015 update: Thomas added support for our QTR-3A Reflectance Sensor Array to his PiBot-A to make a line follower and posted about it on Let’s Make Robots. The sensor array is interchangeable with the array of Sharp digital sensors used for obstacle detection. You can find a video of his robot following a line below:
We have carried the iMAX B6AC charger from SkyRC for many years and often use it to charge batteries for our own projects and robot contests, so we are happy to now be carrying the upgraded iMAX B6AC V2 Balance Charger and Discharger. Both versions of the iMAX B6AC are capable of charging or discharging NiMH, NiCd, Pb, LiPo, Li-ion, and LiFe batteries and can be powered either from AC mains power or a DC input. The new version of the charger has all the same advanced features as the original, like individual cell balancing for up to 6 lithium cells, delta-peak sensitivity, and cyclic charging and discharging. In addition, version two of the charger is more accurate, more stable, and has many new features. Some of the new features include a Micro-USB connection for interfacing with SkyRC’s ChargeMaster PC software and upgrading the firmware, user control over the final battery voltage when charging, individual lithium cell voltage display, and an internal resistance meter.
Bottom view of the iMAX B6AC V2 showing the holographic label with scratch-and-reveal security code.
There are many counterfeit chargers that look almost identical to SkyRC products, so as with the first version, we buy these directly from SkyRC and take care to ensure that our units are genuine. If you would like to double check the authenticity of the iMAX B6AC V2 that you receive, you can reveal the security code under the scratch-and-reveal portion of the holographic label on the bottom of the charger and enter it on the SkyRC web site.
Need batteries for your charger? While we do carry some basic NiMH cells and packs, we recommend that you check out the options at local stores and online, since government restrictions, shipping, and storage issues make this a tough area for a small business to compete in. For larger packs and lithium batteries in particular, there are a number of hobby supply stores shipping from Hong Kong or China that provide excellent options.
For more information about the iMAX B6AC V2 and its features, please see its product page.
One of our customers, Gary, made a heater box and ventilation system for a custom car and posted about it on our forum. His system uses several servos controlled by one of our Micro Serial Servo Controllers. The servos actuate the different valves in his air system to allow him to control the air source as well as things like the defog/defrost system.
Some of the actuated valves on a custom heater box made for a custom car by Gary.
Gary chose to use our board because it allowed him to stop sending signals to the servos when they are not moving. For others considering using our Micro Serial Servo Controller in their next project, we recommend using our Maestro servo controllers instead. They have the ability to stop sending signals to the servos like the Micro Serial Servo Controller and are newer and better in almost every way.
You can find more pictures and read more about Gary’s heater box and ventilation system in his post on our forum.
It has always been possible to control your Maestro Servo Controller from your Arduino-compatible controller with the Maestro’s serial interface, but now it is easier to get started using our new Arduino library. The library implements (and documents) all of the serial commands available on the Maestro controllers and supports all three sub-protocols (Compact, Pololu, and MiniSSC). Continued…
DeWitt Godfrey, a sculptor and professor at Colgate University, used our custom laser cutting service to create a 15% scale polystyrene prototype model before moving on to the final full-sized sculpture. The final installation, located on the Colgate campus, measures approximately 40′ × 20′ and weighs 13 tons. In the video above, the styrene model appears at 2:10, and again at 2:40. You can also see a time-lapse video of the sculpture’s installation here.
15% scale model of Odin, a sculpture by DeWitt Godfrey.
Interior photo of a 15% scale model of Odin, a sculpture by DeWitt Godfrey.