Posts by Kevin

You are currently viewing a selection of posts from the Pololu Blog. You can also view all the posts.

Popular tags: community projects new products raspberry pi arduino more…

Now for Raspberry Pi too: Dual G2 High-Power Motor Drivers

Posted by Kevin on 16 November 2017
Tags: new products

As Jan promised yesterday, our new dual motor drivers are now also available as Raspberry Pi expansion boards! The Dual G2 High-Power Motor Drivers for Raspberry Pi feature two discrete MOSFET H-bridges on a board designed to plug directly into a Raspberry Pi (Model B+ or newer), and they also include an integrated 5 V, 2.5 A switching step-down regulator that allows a single power supply to power both the motors and the Raspberry Pi. We provide a Python library for Raspberry Pi to make it easy to get started using the drivers.

Pololu Dual G2 High-Power Motor Driver 18v22 for Raspberry Pi.

Pololu Dual G2 High-Power Motor Driver 18v18 for Raspberry Pi.

As with the Arduino shield (or standalone) versions, two different PCBs are used for these drivers: the black board has 5×6 mm MOSFETs and the red board has 3×3 mm MOSFETs. Again, each board is available with 30 V or 40 V MOSFETs for a total of four options:


Dual G2 High-
Power Motor Driver
18v22 for Raspberry Pi

Dual G2 High-
Power Motor Driver
18v18 for Raspberry Pi

Dual G2 High-
Power Motor Driver
24v18 for Raspberry Pi

Dual G2 High-
Power Motor Driver
24v14 for Raspberry Pi
Absolute max
input voltage:
30 V 36 V*
Max nominal
battery voltage:
18 V 28 V
Max continuous
current per channel:
22 A 18 A 18 A 14 A
Default active current-
limiting threshold:
60 A 50 A 40 A
Available with
connectors installed?
No Yes No Yes

* 40 V if regulator is disconnected

Unlike the Arduino, the Raspberry Pi does not have analog inputs, so there isn’t an easy way to do current sensing with these boards. However, the current sensing pins are exposed for advanced users who might want to add an external ADC or otherwise make use of the current sense feedback.

Until now, our motor driver offerings for the Raspberry Pi have been limited to our dual MC33926 and DRV8835 add-on boards, which handle much less current. One of our other favorite integrated motor drivers, the VNH5019, would have been a nice step up in power from the MC33926, but it has one big downside…literally. Its footprint measures around 17 mm by 19 mm, and you can see that on our dual VNH5019 Arduino shield, the two driver ICs take up most of the width of the board:

Pololu dual VNH5019 motor driver shield for Arduino.

We try to make our Raspberry Pi expansion boards conform to the HAT (Hardware Attached on Top) mechanical specification when we can, and that spec recommends including a slot in the middle of the board to accommodate a flex cable plugging into the Raspberry Pi’s camera connector.

Raspberry Pi HAT mechanical specification drawing.

Combined with the cutout for the other flex connector, this space limitation means that it would be difficult—if not impossible—to make a VNH5019 motor driver expansion board for the Raspberry Pi that is not annoyingly obstructive. So we are excited that the G2 design, with its discrete MOSFET H-bridges, provided enough layout flexibility for us to create these high-power dual motor driver expansions without making such compromises. We hope that they will open up new possibilities for bigger and more powerful Raspberry Pi robots!

Happy Halloween!

Posted by Kevin on 31 October 2017
Tags: halloween

Another Halloween means another batch of great costumes from the people at Pololu!

Highlights from this year include Jennifer’s impressively detailed Ghostbuster costume, complete with a “working” proton pack (well, at least the lights worked) built around some laser-cut parts…

and Jon’s elaborate representation of the Cassini-Huygens spacecraft, which included an actual magnetometer on the tip of his boom and a buzzer to audibly indicate magnetic measurements.

Did you use any Pololu products in your Halloween costume or decorations? We’d love to hear about it on our forum or in the comments below, and we might even feature it in a future blog post!

Have a Happy Halloween!

Beefy arms for Balboa balancing robot

Posted by Kevin on 24 March 2017


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.

UM7-LT and UM7 orientation sensors now from Redshift Labs

Posted by Kevin on 13 October 2016
Tags: new products

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.

UM7-LT orientation sensor.

UM7 orientation sensor with included cable and U.S. quarter for size reference.

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.

New product: Magnetic Encoder Pair Kit for Mini Plastic Gearmotors

Posted by Kevin on 18 August 2016
Tags: new products

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.

A Raspberry Pi robot without a HAT

Posted by Kevin on 15 August 2016

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.

New product: VL53L0X Time-of-Flight Distance Sensor Carrier

Posted by Kevin on 9 August 2016
Tags: new products

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.

New version of our USB Micro-B breakout

Posted by Kevin on 11 July 2016
Tags: new products

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.

New 12 V micro metal gearmotors

Posted by Kevin on 8 July 2016
Tags: new products
New 12 V micro metal gearmotors

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
Motor Type Stall
Current
@ Rated Voltage
No-Load
Speed
@ Rated Voltage
Approximate
Stall Torque
@ Rated Voltage


Single-Shaft
(Gearbox Only)


Dual-Shaft
(Gearbox & Motor)
12 V high-power,
carbon brushes
(HPCB)
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
Continued...

New version of the Wixel Shield for Arduino

Posted by Kevin on 14 April 2016

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.

New Products

Pololu Dual G2 High-Power Motor Driver 18v18 Shield for Arduino
3.3V Step-Up/Step-Down Voltage Regulator w/ Adjustable Low-Voltage Cutoff S9V11F3S5CMA
Pololu Dual G2 High-Power Motor Driver 18v18 for Raspberry Pi (Assembled)
Pololu Dual G2 High-Power Motor Driver 18v22 for Raspberry Pi (Partial Kit)
Pololu Dual G2 High-Power Motor Driver 24v18 Shield for Arduino
Parallax Feedback 360° High-Speed Servo
Pololu Dual G2 High-Power Motor Driver 24v18 for Raspberry Pi (Partial Kit)
Pololu Dual G2 High-Power Motor Driver 24v14 for Raspberry Pi (Assembled)
FEETECH Standard Servo FS5103B
2.5-9V Fine-Adjust Step-Up/Step-Down Voltage Regulator w/ Adjustable Low-Voltage Cutoff S9V11MACMA
Log In
Pololu Robotics & Electronics
Shopping cart
(702) 262-6648
Same-day shipping, worldwide
Menu
Shop Blog Forum Support
My account Comments or questions? About Pololu Contact Ordering information Distributors