Posts by Kevin
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We’ve updated our Wixel Shield for Arduino with a few minor improvements. The Wixel Shield provides an easy way to connect a Wixel wireless module to your Arduino or A-Star 32U4 Prime, enabling wireless communication and even wireless programming (on some Arduinos). However, the original version of the shield was released many years ago, so it was not designed with the modern pinout of the Arduino Uno R3 in mind.
The Wixel Shield v1.1 adds pass-throughs for the four new pins—SCL, SDA, IOREF, and an unused pin—introduced by the R3 and present on all newer Arduinos, making it easier to stack other shields with it (especially ones that make use of the new I²C pin location). It also features improved level shifter circuits that make use of the IOREF voltage provided by the Arduino, allowing the shield to work automatically with both 5 V and 3.3 V Arduino boards.
The Wixel Shield for Arduino v1.1 is available by itself and as part of a combination deal that includes a pair of Wixels and a USB cable. See the user’s guide for the shield for additional information.
Our second-generation family of high-power motor drivers continues to grow with the release of our G2 High-Power Motor Driver 18v25 and G2 High-Power Motor Driver 24v21, discrete MOSFET H-bridges that can supply a brushed DC motor with up to 25 A of continuous current at up to 30 V or up to 21 A of current at up to 40 V, respectively. In addition, we’ve lowered the prices of the 18v17 and 24v13 versions to make them even more affordable.
The new G2 18v25 and G2 24v21 drivers’ double-sided design allows them to retain the same board dimensions as their 18v17 and 24v13 siblings, even though they can deliver significantly more power. The G2 drivers are half an inch shorter and can handle the same (or slightly more) current compared to the original 18v25 and 24v20 they are designed to replace, and they are less than half the size of the original 18v25 CS and 24v23 CS while offering basic current sensing functionality that can eliminate the need for a dedicated current sensor in some applications. As with previous G2 drivers, they also include reverse-voltage protection and a current limiting feature.
|Pololu G2 High-Power Motor Driver 24v21 next to original high-power motor driver 24v20 and 24v23 CS.|
|Pololu G2 High-Power Motor Driver 24v21 and 24v13.|
For more information about the G2 motor drivers, see their product pages at the links below.
Our A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge is now available, joining the LV version we released six months ago.
Similar to its lower-voltage sibling, the Robot Controller SV is a general-purpose robot controller that includes dual motor drivers and other useful peripherals like pushbuttons and a buzzer. It also has the same level shifters and power circuit that allow it to easily power and communicate with a Raspberry Pi when mounted as an auxiliary controller. Like our other A-Star controllers, the A-Star Robot Controller SV built around an ATmega32U4 microcontroller and ships preloaded with an Arduino-compatible USB bootloader.
This SV version of the A-Star Robot Controller uses an efficient step-down switching regulator, enabling it to operate (and optionally supply power to an attached Raspberry Pi) with input voltages from 5.5 V to 36 V. Compared to the LV version, the Robot Controller SV can also supply substantially more current across its wide operating voltage range:
We’ve been working on some (long-awaited) I²C software to allow the A-Star to be used as a slave controller with a Raspberry Pi master, as well as an example project that shows how to build a robot with this setup. They’re nearly ready, so watch for them on the blog in the coming weeks. But don’t forget that the A-Star board can also be used by itself as a capable robot controller, as my recent sumo robot demonstrates.
To facilitate both of these uses, the A-Star 32U4 Robot Controller SV is available either assembled for use as a Raspberry Pi add-on or in a more barebones configuration that is suitable for customized assembly or standalone use. See those product pages and the user’s guide for more information about the robot controller.
As with other ST sensors, these chips can be configured and read through I²C or SPI interfaces, and our compact breakout boards incorporate voltage regulators and level shifters to make them easier to use with 5 V systems. Compared to the inertial and magnetic sensors we’ve used previously (most recently the LSM303D accelerometer and magnetometer and the L3GD20H gyro), these two new ICs offer different combinations of capabilities: the LSM6DS33 integrates an accelerometer and rate gyroscope into a single package, while the LIS3MDL is a standalone magnetometer.
For more information about these boards, see their product pages at the links below.
We now have three "Pi"s! …No, I’m not talking about our 3pi robot.
In addition to the Raspberry Pi Model B+ we’ve been carrying, we now offer the smaller Raspberry Pi Model A+ and the more powerful Raspberry Pi 2 Model B as well. Check out their product pages for details about each version and how they compare to each other.
|Raspberry Pi Model B+.|
As with the B+, the A+ and 2 B are compatible with our Raspberry Pi expansion boards, including our A-Star 32U4 Robot Controller with Raspberry Pi Bridge and our MC33926 and DRV8835 motor driver add-ons.
This discrete MOSFET H-bridge can supply a brushed DC motor with up to 17 A of continuous current at voltages between 6.5 V and 30 V. Compared to its predecessor, the G2 driver handles a little more current and offers features like reverse-voltage protection, current sensing, and current limiting. For more information, see its product page.
Robot enthusiasts: if you want to show your Pololu pride but covering yourself with Pololu stickers just doesn’t seem fashionable, we’ve got good news for you! Our new Zumo T-shirts are here, featuring a Zumo 32U4 robot within a sprocket-inspired border, accompanied by our call to “Engage Your Brain”. These pre-shrunk cotton shirts are available in several colors (royal blue, cardinal red, or charcoal gray) and a range of sizes.
My robot, Roku, was the champion of LVBots’ August mini-sumo competition. While I didn’t have the time or inspiration to make it look like anything more interesting (like a Star Wars droid) or make use of especially innovative tactics, I think I managed to build a robot that not only is effective but also looks fairly clean and well put together. In addition, it’s a good demonstration of how the Pololu A-Star 32U4 Robot Controller can be used as a standalone main board for a small robot. Continued…
We are excited to announce the release of the Pololu G2 High-Power Motor Driver 24v13. Like our original high-power motor drivers, this board is a discrete MOSFET H-bridge that is designed to drive large DC brushed motors. As the first of our second-generation high-power motor drivers, the 24v13 can supply a motor with a continuous current as high as 13 A at voltages between 6.5 V and 40 V (absolute maximum).
The G2 driver is designed to be a near drop-in replacement for its predecessor, with an identical form factor and a similar pinout, but it offers a number of new features and improvements over the older version. Reverse-voltage protection on the power supply inputs helps prevent instant destruction if a battery is connected backwards, while basic current sensing and limiting functionality help the driver handle large loads more gracefully. The G2 driver is also compatible with systems running at 3.3 V (and lower), unlike our original high-power motor drivers.
To learn more about the motor driver’s features and capabilities, see its product page.
There’s another new product coming out of the assembly line here at Pololu: the VL6180X Time-of-Flight Distance Sensor Carrier. The VL6180 from ST Microelectronics distinguishes itself from other optical sensors by using time-of-flight measurements to determine distance: it emits pulses of infrared laser light and precisely times how long they take to reach the nearest object and reflect back to the sensor, which means it is essentially a complete short-range lidar system in a single tiny package.
With this technique, the VL6180X can accurately measure the absolute distance to a target object from 0 cm to at least 10 cm away – sometimes up to 20 cm away, depending on the target and environment – without being affected by what color the target is or how reflective it is.
|VL6180X datasheet graph of typical ranging performance.|
Distance readings can be obtained through the sensor’s I²C interface (in units of millimeters – no complicated conversions necessary!). The VL6180X also includes an ambient light sensor; this combination of sensing capabilities is useful for applications, including smartphones, for which the VL6180 was designed.
The VL6180X IC by itself is a challenge to use because of its small surface-mount package and particular voltage requirements, so our breakout board includes a 2.8 V regulator and level shifters that allow it to be used with 3.3 V and 5 V systems. The carrier board provides a breadboard-friendly pinout and mounting holes while remaining as compact as possible (0.5″ × 0.7″). We’ve also written an Arduino library for the VL6180X that makes it easy to get started with this board.
For more information about the VL6180X carrier, see its product page.