Posts by Kevin
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If you’re following Paul’s blog series about getting your Balboa robot balancing, you’ll probably want something to protect it when it falls. When I was working with my Balboa, I got a set of prototype arms that our mechanical engineers have been developing, but I felt they were missing a little something. So instead, I took a Beefy Arm Starter Kit from Thingiverse and used OpenSCAD to add adjustable mounting hubs to the arms. I printed two sets of arms with our RigidBot 3D printer and mounted them to the side rails on the Balboa chassis using 25 mm M3 screws and M3 nuts. They’ve been great for keeping obstacles and the floor at arm’s length from my electronics while I drove the robot around with an RC transmitter or through a Raspberry Pi web interface (example code coming soon!).
You can find these beefy arms for the Balboa on Thingiverse if you want to try 3D printing your own. The OpenSCAD script is also available there in case you want to customize your arms.
The UM7-LT and UM7 orientation sensors, originally developed by CH Robotics, are now being manufactured and supported by Redshift Labs. The updated versions of these sensors are now available from Pololu.
The UM7 is an Attitude and Heading Reference System (AHRS) that takes measurements from its three-axis accelerometer, gyro, and magnetometer and calculates orientation estimates with its integrated microcontroller. It is available with an enclosure as the UM7 or without one as the UM7-LT. Aside from a few updated components and the addition of a conformal coating on the UM7-LT, these sensors are functionally identical to the original versions produced by CH Robotics.
For more information about the orientation sensors, see their product pages below.
We now have a magnetic encoder pair kit available for our mini plastic gearmotors with extended back shafts. Like our encoder kit for micro metal gearmotors, these kits consist of Hall effect sensor boards that mount to the back of the motors and magnetic discs that fit on the motors’ back shafts. The encoders provide a resolution of 12 counts per revolution of the motor shaft (when counting both edges of both channels); in terms of counts per gearbox output shaft revolution, the resolution is multiplied by the corresponding gear ratio.
For more details about the encoder kit, see the product page.
Using an Arduino shield or Raspberry Pi add-on board is often a quick and convenient way to get started on a robotics project, but for maximum flexibility, nothing beats building your own system from standalone boards. Rud Merriam’s Hackaday article describes the design of his Raspberry Pi-controlled robot, for which he opted to use separate modules instead of daughterboards on the Pi, and mentions some of the trade-offs involved in making that decision.
The robot is built on a Wild Thumper chassis and uses a Maestro USB servo controller and two Simple Motor Controllers to interface the Raspberry Pi with the robot’s motors and actuators. In Rud’s writeup, he explains how he made use of some of the more advanced features of the Maestro and SMCs, like using servo channels for general-purpose I/O and setting up daisy-chained serial communications. Check out the full article for all of the details.
We’ve just released our VL53L0X Time-of-Flight Distance Sensor Carrier. With its ability to measure distances up to 2 m depending on configuration, target, and environment, the VL53L0X is a longer-range version of the VL6180X (but without ambient light sensing functionality) that operates using the same principles. This integrated lidar module times how long it takes for pulses of infrared light to reach a target, reflect off it, and arrive back at the sensor. It uses this information to report the range to the target with a resolution of 1 mm and accuracy as good as ±3%, minimizing the effect of the target’s reflectance on the measured distance.
VL53L0X datasheet graph of typical ranging performance (in default mode).
As usual, our breakout board adds a 2.8 V regulator and level shifters to help interface with 3.3 V and 5 V systems, as well as a breadboard-compatible pinout and mounting holes. We are also working on an Arduino library for the VL53L0X that we expect to release in the next few days.
For more information about the VL53L0X carrier, see its product page.
We’ve updated our USB Micro-B Connector Breakout Board with some minor improvements that should make it a little nicer to work with.
On the original version, the mounting cutouts didn’t work as well as we wanted: they were shallow, and the board was often prone to slipping out of place between two screws. The new version is wider and its cutouts are deeper to allow for more secure mounting, and it is slightly shorter in the other direction (0.4″ × 0.6″ with the connector).
For more information, see the board’s product page.
Our micro metal gearmotors are now available in 12 V versions! These high-power motors have long-life carbon brushes (HPCB) and offer the same performance as the 6 V HPCB motors at their respective nominal voltages; the only difference is that the 12 V motor draws half the current at twice the voltage.
The new 12 V gearmotors are available across our usual range of 11 gear ratios and in single- and dual-shaft versions. Along with our existing selection of micro metal gearmotors, this brings the total number of unique options available to 107:
@ Rated Voltage
@ Rated Voltage
@ Rated Voltage
(Gearbox & Motor)
|800 mA||6000 RPM||2 oz-in||5:1 HPCB 12V||5:1 HPCB 12V dual-shaft|
|3000 RPM||4 oz-in||10:1 HPCB 12V||10:1 HPCB 12V dual-shaft|
|1000 RPM||9 oz-in||30:1 HPCB 12V||30:1 HPCB 12V dual-shaft|
|625 RPM||15 oz-in||50:1 HPCB 12V||50:1 HPCB 12V dual-shaft|
|400 RPM||22 oz-in||75:1 HPCB 12V||75:1 HPCB 12V dual-shaft|
|320 RPM||30 oz-in||100:1 HPCB 12V||100:1 HPCB 12V dual-shaft|
|200 RPM||40 oz-in||150:1 HPCB 12V||150:1 HPCB 12V dual-shaft|
|140 RPM||50 oz-in||210:1 HPCB 12V||210:1 HPCB 12V dual-shaft|
|120 RPM||60 oz-in||250:1 HPCB 12V||250:1 HPCB 12V dual-shaft|
|100 RPM||70 oz-in||298:1 HPCB 12V||298:1 HPCB 12V dual-shaft|
|32 RPM||125 oz-in||1000:1 HPCB 12V||1000:1 HPCB 12V dual-shaft|
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.