Posts tagged “arduino” (Page 3)
You are currently viewing a selection of posts from the Pololu Blog. You can also view all the posts.
I am excited to announce our new A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge, a general-purpose robot controller based on Atmel’s ATmega32U4 microcontroller.
This new robot controller is the latest model in our A-Star line of Arduino-compatible USB microcontroller boards. We started with the A-Star 32U4 Micro and have been gradually expanding the line, adding peripherals and various form-factor and voltage options, with the goal of eventually replacing our older Orangutan robot controllers. The Zumo 32U4 was a major step in that direction, since its controller board is essentially an A-Star 32U4 plus extra peripherals for motor control and sensing. But while the Zumo 32U4 is a complete robot kit, this board is for people who want to design their own robot.
The A-Star 32U4 Robot Controller LV includes most of the features of the A-Star 32U4 Prime LV, including an Arduino-compatible USB bootloader, an efficient step-up/step-down regulator, and handy peripherals like the buzzer and buttons, and it expands on the A-Star line by adding a pair of Texas Instruments DRV8838 1.8 A motor drivers, the same motor drivers as on the Zumo. All of the AVR’s GPIO lines are broken out, and we have included handy power and ground rails so you can easily connect lots of things like servos and sensors:
This board is well-suited for small robots that would have otherwise used an Orangutan controller like the SV-328 or SVP-1284. While we did not include an LCD like on the Orangutans, you can get far better display, monitoring, or data logging by making use of the Raspberry Pi connection, which I will talk about next.
Using the robot controller with a Raspberry Pi
The Raspberry Pi is a great board for an embedded project that needs serious computational power or connectivity. We have released a couple of Raspberry Pi motor driver boards over the past year, which give you a way to get started exploring robotics with your Raspberry Pi. But robotics projects tend to use a lot of analog sensors, timing-sensitive devices like servos, and other peripherals that are not compatible with the limited I/O capabilities of the Raspberry Pi. These types of things are what microcontrollers are designed for, so you can do a lot more if you pair your Raspberry Pi with a complete microcontroller board.
That’s why instead of using the standard Arduino form factor like the Prime, we built the A-Star 32U4 Robot Controller LV to double as a Raspberry Pi HAT:
A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge on a Raspberry Pi Model B+.
The Robot Controller fits on top of a Raspberry Pi A+/B+/2, powers the Pi, and connects to it as an I²C slave device, giving you a bidirectional channel of communication between the two processors. We have broken out all of the GPIO of the Raspberry Pi, and there are a few general-purpose level-shifters included on the board to help you experiment with other communications protocols or interface other hardware to your system. We even include the EEPROM required by the HAT specification, though we have not found it to be particularly useful – we ship it blank and unlocked for you to experiment with.
For more information about the A-Star 32U4 Robot Controller LV, or to order, see the product page. You can also check out our open-source A-Star 32U4 Arduino library, which provides easy access to the main features of the Robot Controller, including its motor drivers; we will be adding examples showing I²C communication with the Raspberry Pi soon.
Tomorrow is Arduino Day, and we are joining in on the fun by offering big discounts on many of our Arduino-related products, including our A-Star programmable controllers and Arduino shields. The sale has already started, and it will run through the end of Sunday (I know, Arduino Day is a one-day event, but this makes sure the sale lasts all Arduino Day in every time zone). You can find all of the sale items on our Arduino Day 2015 sale page.
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.
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…
It has been snowing on and off today in Las Vegas, but luckily the weather was not bad enough to delay our last product release of 2014: the A-Star 32U4 Prime SV. We hope that this and the other A-Stars we released this year will help bring success to your projects in 2015. Thanks for your business and support in 2014, and Happy New Year!
The A-Star 32U4 Prime SV, our newest A-Star, is an Arduino-compatible board with a switching regulator that allows an input voltage range of 5 V to 36 V. Like the A-Star 32U4 Prime LV we released earlier this month, the A-Star 32U4 Prime SV shares the pinout and form factor of the Arduino Leonardo and should work with compatible shields.
What really sets the A-Star 32U4 Primes apart from competing products is their power supply system based on high-efficiency switching regulators, which allow plenty of power to drive your microcontroller and lots of peripherals over a large range of input voltages. The A-Star 32U4 Prime SV uses the Intersil ISL85410 1-Amp buck regulator, a more powerful relative of the regulator on A-Star 32U4 Mini SV. So you get 1 A at 5 V over most of the SV input voltage range. (We recommend an input voltage of at least 6 V.) And since a switching regulator draws less current as the voltage increases, you can get a lot more out of higher-voltage power supplies and battery packs. In a typical usage scenario, if you power your project with a 12 V battery, the A-Star 32U4 Prime SV will draw about half the current of a competing product with a linear regulator – and last twice as long on a single charge.
A-Star 32U4 Prime power distribution diagram (original ac03b version).
Like the A-Star 32U4 Prime LV, the SV has a bunch of features designed to make it easy for you to make use of the power. The TPS2113A USB power mux allows you to safely and seamlessly switch between a battery and USB power (up to 1.5 A using a powerful enough USB supply), without the limitations of diodes or fuses. We included a handy power switch for your external power input, extra connection options in case you don’t want to use the standard DC power jack, extra access points for the important power nodes VIN, VREG, 5V, and 3V3, and big power and ground buses.
The A-Star 32U4 Prime SV includes all the same peripheral features as the A-Star 32U4 Prime LV: battery voltage monitoring, three user pushbuttons (sharing the MISO, RXLED, and TXLED lines), a buzzer optionally controlled by digital pin 6, a connector for an HD44780-based character LCD, and – on some models – a microSD card slot that works with the Arduino SD library. Here is an SV with all the optional peripherals installed:
You can purchase this configuration pre-assembled as Pololu item #3115, or get it with almost everything but the LCD as Pololu item #3114. (You can still install an LCD yourself later.) For other configuration options, please see the individual product pages below or the A-Star 32U4 Prime SV category page.
The A-Star 32U4 Prime LV is the newest member of our A-Star family of programmable microcontroller boards. This is the first Pololu board with the familiar Arduino shape: it shares the pinout of the Arduino Leonardo and should work with Leonardo-compatible shields. With some code changes, this A-Star can also serve as a substitute for the similar Arduino Uno in many projects. However, there is a lot more to it than Arduino compatibility!
Unlike the Uno and Leonardo, the A-Star Prime has an efficient 5 V switching regulator and a seamless USB power switching circuit. This “LV” model uses the same power circuit, based on the Texas Instruments TPS63061 and TPS2113A, as the A-Star 32U4 Mini LV. Like that board, the A-Star 32U4 Prime LV can operate from 2.7 V to 11.8 V and supply about 1 A at 5 V, safely and efficiently switching between USB and external power without the limitations of components like fuses or diodes. It also includes a power switch, multiple power input connection points, and optional battery voltage monitoring, making it convenient to use in a variety of power supply scenarios. Here is a diagram of power distribution on the board:
As you can see in the pictures, there are few extra rows of pins next to the normal Arduino headers. The point of these is to give you more connection options: we have included an extra access point (on a 0.1" grid) for most of the pins, as well as extra power and ground buses. The power buses are unconnected by default, so you could, for example, wire VIN directly to a bus and solder in servo connectors in one place (the LV regulator works great on a four- or five-cell NiMH pack), while having another bus run at 3.3 V to power an array of low-voltage sensors. As another example, these buses are a convenient place to add your own custom pull-up or pull-down resistors.
There is a lot of space available in this form factor compared to the typical Pololu breakout board, and we hate to waste space, so we packed it with extra, optional peripherals:
You might recognize some of the optional peripherals from our line of Orangutan Robot Controllers and the 3pi Robot. These are features that we have found really handy in our projects over the years: three user pushbuttons (sharing the MISO, RXLED, and TXLED lines), a buzzer for beeps and simple music (optionally controlled by digital pin 6), and a connector for an HD44780-based character LCD. You can enable just the features you want with jumpers; the ones you do not use will not interfere with shields or other electronics. On some models, we are also including a microSD card slot that works with the Arduino SD library, so you can easily turn your A-Star Prime into a datalogger or access large scripts and media files.
Here is what the A-Star 32U4 Prime LV looks like with all optional peripherals installed:
This configuration is available pre-assembled as Pololu item #3109, while a configuration including pretty much everything but the LCD is available as Pololu item #3108. (You can still install an LCD yourself later.) For other configuration options, please see the individual product pages below or the A-Star 32U4 Prime LV category page.
If you have been following our blog, you have seen some fun and scary Halloween projects posted by my coworkers here at Pololu. Well, this is the first part of my prop for my costume for this upcoming Halloween. After watching an animatronic devil baby terrorize New York City, I knew I wanted to build a similar demon baby that would be attached to me with a baby carrier. Continued…
We are excited to announce the addition of two new motor drivers to our selection of Arduino shields: the Pololu DRV8835 Dual Motor Driver Shield for Arduino and the Pololu A4990 Dual Motor Driver Shield for Arduino. These miniature shields are low-cost, basic dual motor drivers for your Arduino or Arduino-compatible board. When connected to an Arduino, each provides two channels of bidirectional PWM motor control suitable for driving small brushed DC motors. The boards include various handy features like reverse protection, multiple power and motor connection options, and the ability to customize some of the pin mappings. Our open-source libraries provide a convenient way to get started controlling these motors with an Arduino.
Selecting a motor driver shield
Pololu DRV8835 Dual Motor Driver Shield for Arduino, top and bottom sides.
Pololu A4990 Dual Motor Driver Shield for Arduino, top and bottom sides.
The main practical difference between the shields is their input voltage range, so most people should probably select a shield based on their desired power supply. Here are some details:
Our DRV8835 shield, based on the DRV8835 motor driver from Texas Instruments, has an input voltage range of 2 V to 11 V and can deliver a continuous 1.2 A (1.5 A peak) on each channel. It is suitable, for example, for battery-powered robots similar to the 3pi or Zumo. As a bonus feature of our shield, you can parallel the motor outputs to get a single channel with twice the current capability.
Our A4990 shield uses the Allegro A4990 and is specifically intended for higher-voltage applications, such as projects powered by a 12 V or 24 V battery. It has an input voltage range of 6 V to 32 V and can deliver a continuous 0.65 A (0.9 A peak) per channel. The A4990 can detect and signal a variety of errors like over-temperature and short-circuit, allowing more sophisticated control and monitoring.
Basic breakout boards available
Congratulations to our summer interns!
If you carefully inspect the back of the boards, you will notice “TKern” and “izzyg” etched in copper. These inscriptions commemorate the internships of Ted Kern and Ismael “Izzy” Gomez, Las Vegas natives who were indoctrinated in Pololu design philosophies this summer while creating these new products. We wish Ted and Izzy good luck as they head/return to college at CMU and MIT!
Adding wireless connectivity to an electronics project is a great way to enhance functionality and make it stand out. Our selection of wireless electronics includes radio frequency modules, such as the Wixel, and Bluetooth modules, like the BlueSMiRF Silver from SparkFun, but until recently, we did not carry a good solution to adding Wi-Fi to a project. That’s where the newest additions to our wireless selection come into play.
We are now carrying two CC3000 Wi-Fi module carrier boards from Adafruit: the CC3000 Wi-Fi Shield for Arduino and CC3000 Wi-Fi breakout board. The CC3000 is a self-contained wireless network processor with an SPI interface, so it is not limited to a fixed UART baud rate, and the Adafruit carrier boards include level shifters, so they should be simple to connect to almost any microcontroller. Adafruit’s CC3000 Arduino library and example sketches make them especially easy to use with an Arduino-compatible board.
The CC3000 Wi-Fi Shield for Arduino offers a MicroSD card socket, a prototyping area for soldering extra circuitry, and a button for resetting the Arduino. The CC3000 Wi-Fi breakout board (v1.1) is much more compact and is also breadboard-compatible. Both products include an onboard ceramic antenna.
A few months ago, we released the A-Star 32U4 Micro, a general-purpose microcontroller breakout board based on the Atmel ATmega32U4, and we discussed our plans to extend the design with additional integrated features. Today, we are thrilled to announce a major expansion of the family with the introduction of the A-Star 32U4 Mini ULV, A-Star 32U4 Mini LV, and A-Star 32U4 Mini SV.
A-Star 32U4 Mini pinout diagram (listed SV voltage range is for original ac02c version).
Like the A-Star Micro, the A-Star Minis are Arduino-compatible boards based on the ATmega32U4. The Minis are expanded boards that provide access to almost all of the pins of the AVR (including a few more than the Arduino Leonardo and Arduino Micro), but what really sets them apart from competing products are their efficient power supply systems based on switching regulators. Each model is based on a different voltage regulator, and its name includes a designation corresponding to its input voltage range:
- A-Star 32U4 Mini ULV (Ultra-Low Voltage): 0.5 V to 5.5 V
- A-Star 32U4 Mini LV (Low Voltage): 2.7 V to 11.8 V
- A-Star 32U4 Mini SV (Standard Voltage): 5 V to 36 V
Typical maximum output current of the regulators on the A-Star 32U4 Mini boards.
The regulator designs are closely related to some of our favorite voltage regulator boards, the U1V11F5, S7V8F5, and D24V5F5. Taken together, this range of options lets you power your project with anything from a single NiMH cell to a 24 V lead-acid battery or an 8-cell LiPo pack. With typical currents of 500 mA to 1 A, you get plenty of 5 V power for your AVR and an array of peripheral devices, or at the other end of the scale, these regulators allow your project to make effective use of low-power modes on the AVR, potentially operating on a battery for months at a time.
A-Star 32U4 Mini ULV, bottom view with dimensions.
Another exciting feature of the power supply system on the A-Star Minis is seamless USB power switching provided by an onboard TPS2113A power multiplexer. This means that you can safely connect both USB and external power, and you can monitor or control the selected supply, without losing power or shorting your supplies together.
We think that the A-Star Minis are by far the most capable AVR breakout boards for their size, and they should be an excellent choice for almost any project needing a compact, Arduino-compatible controller. We have priced them so that it should be an easy choice, too. For more information or to order, see the A-Star controller category.