You are currently viewing a selection of posts from the Pololu Blog. You can also view all the posts.
On March 6, LVBots held another competition at Pololu. This time, it was a dead reckoning contest: each robot had to find a line course and follow it to its end while keeping track of its position, then try to return to its starting position without any external navigational aids. Scoring was based on how close to the starting position the robot ended up, as well as how quickly it got there. The complete rules are available here (23k pdf). You can see a selection of the entries in this video compilation from the contest.
David has already posted about his entry. My robot was R2-DR, the miniature astromech droid, and I’ll be writing a post about it soon, too.
Are you in the Las Vegas area? Check out the LVBots Meetup page and drop by this Thursday, March 20, to see the robots in person!
Updates: You can read more about each of our robots in these blog posts:
- David and Fang’s dead reckoning robot based on the mbed LPC1768
- Brandon’s dead reckoning robot
- R2-DR, Kevin’s dead reckoning robot
- Claire’s dead reckoning robot
- Paul’s dead reckoning robot
- Jon’s dead reckoning robot
- Jamee’s dead reckoning robot
When we designed the first version of the Pololu USB-to-serial adapter way back in 2004, using a USB Mini-B receptacle was an obvious choice: it was much smaller than the standard B-type connector, allowing us to keep the board compact, and it was readily available in surface-mount configurations that facilitate automated printed circuit board assembly.
We went on to use the Mini-B connector in lots of products, like our Maestro servo controllers and Wixel. Although the even smaller Micro-B connector became part of the USB specification in 2007, it didn’t seem to offer enough of an advantage over the Mini-B connector for us to immediately switch over. Continued…
We’ve started selling USB versions of these two RoboClaw motor controllers from Orion Robotics:
These new RoboClaws add a USB serial interface to the other three control interfaces available (TTL serial, RC, and analog inputs), but are otherwise identical to the V4 RoboClaw 2×15A and 2×30A controllers that we previously offered. Like their predecessors, they can drive a pair of brushed DC motors with up to 15 A or 30 A, respectively, at voltages from 6 V to 34 V. Integrated dual quadrature decoders make it easy to create a closed-loop speed control system; analog feedback is also supported for closed-loop position control.
This data logger shield from Adafruit provides an easy way for your Arduino to save data so you can process and analyze it later. It accepts any SD card formatted with a FAT16 or FAT32 file system, and it includes a real-time clock (RTC) for accurate timestamping of your data. Lots of documentation and resources are available from Adafruit to help you get started with the shield.
For more information, see the Adafruit Data Logging Shield for Arduino product page.
Get a FREE copy of Elektor magazine’s January/February issue with your order while supplies last. To get your free issue, enter the coupon code ELEKTOR0114 into your shopping cart. The magazine will add 8 ounces to the package weight when calculating your shipping options.
For other issues and more information, see our Free Elektor Magazine Offers page. All issues are now available for shipping worldwide!
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.
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.
As smartphones and tablets become more popular and more advanced, they drive the rapid development of progressively better and cheaper inertial sensors, and we’ve come to expect a new 3D compass/accelerometer chip from ST every year or so. We’re catching up again with their latest technology (for the time being) with the release of our LSM303D 3D compass and accelerometer carrier.
The LSM303D offers a number of improvements over its predecessors, including a wider maximum magnetic sensing range (up to ±12 gauss). It also features a more unified I²C interface and adds support for SPI communication. Our carrier board includes a 3.3 V voltage regulator and level shifters that make it easy to use with 5 V systems. For more information, see the product page.
Forum user Jim Remington has been working on getting the Talkie speech synthesis library to run on an Orangutan robot controller. The Talkie library, written by Peter Knight for the Arduino, has its roots in a Texas Instruments speech synthesis system that dates from the 1970s and was used in the Speak & Spell educational toy.
When we read about what Jim was doing on the Pololu Forum, we wanted to try it ourselves. We modified Jim’s Orangutan LV-168 code to work on the Orangutan SV-328, and we discovered that the Orangutan’s motor driver could be used as an improvised audio amplifier. This video demonstrates the result:
(Yes, those numbers are a little implausible, but they’re a good way to show off Jim’s number-to-speech routine.)
We’ve just released a new USB-to-serial adapter based on the Silicon Labs CP2104 USB-to-UART bridge. This tiny, inexpensive board makes it easy to connect a logic-level serial device to a PC, offering access to all of the data, control, and GPIO pins on the CP2104 while measuring only 0.6″ × 0.95″, including its Micro-USB connector. The adapter’s versatile pinout allows it to be used in a number of different ways, including on a breadboard or as a six-pin FTDI cable replacement.
And in case you don’t have a compatible cable lying around, we now also carry Micro-USB cables in two varieties: a standard cable that works with high-speed USB devices, and a thinner version that is lighter and more flexible but limited to low- and full-speed USB.