Pololu Blog (Page 36)
Welcome to the Pololu Blog, where we provide updates about what we and our customers are doing and thinking about. This blog used to be Pololu president Jan Malášek’s Engage Your Brain blog; you can view just those posts here.
We are pumped to announce that we are now carrying Advancer Technologies’ MyoWare Muscle Sensor!
This sensor features a number of improvements over the older Muscle Sensor v3 including single-supply operation (no need for a negative voltage supply) and built-in snap connectors for electrodes. Other new features include a raw EMG output, reverse power protection, a power switch, LED indicators, and two mounting holes.
For a fun example that shows how you could use the muscle sensor, take a look at this blog post, which uses one of our Maestros to monitor a bicep while it is flexing, and command a servo to imitate the motion with a tiny cardstock version of He-Man’s arm. (Note that the project uses the older Muscle Sensor v3, not this new product.) You can also head on over to Advancer Technologies’ website for more project ideas.
Before I started designing my entry into this year’s LVBots mini sumo competition, I watched several videos of other competitions. I noticed a majority of the victories came from engaging the opponent from the side or back; a pattern I also noticed during the last LVBots mini sumo competition. For that competition, I made a robot that used a blade and sensors on the front and back of the robot (basically making the robot have two fronts and no back). However, my strategy in that competition was to roam the ring and search for the opponent, which I suspect increased the chances of the opponent engaging from a suboptimal angle. This time, I wanted to try having my robot spin in place looking for the opponent and striking once it was found. This ultimately resulted in my newest mini sumo robot, Black Mamba. For those unfamiliar, a black mamba is a snake with a reputation for being highly aggressive and is one of the longest and fastest-moving snakes in the world. A black mamba’s venom is highly toxic, and it is capable of striking at considerable range, occasionally delivering a series of bites in rapid succession. Black Mamba is also Kobe Bryant’s self-appointed nickname (yes, I am a Lakers fan). Continued…
It has been a few months since we introduced our new high-power micro metal gearmotors with longer life carbon brushes. We now have them available with dual shafts, and we have made a corresponding update to our magnetic encoders to let them work with the larger terminals of the HPCB motors.
You might see similar-looking motors elsewhere, but no one comes close to our offering, from the quality of the gears to the variety of winding options to the selection of gear ratios, all in stock for shipment the day you order. By bringing together Pololu’s exclusive features of high-power windings, long-life carbon brushes, and encoders for closed-loop feedback control into a single package, these latest motors and encoders really demonstrate our continual investment in this popular form factor. With ten gear ratios available, from 10:1 through 1000:1, our total selection of micro metal gearmotors has grown to nearly 70 options:
@ 6 V
@ 6 V
@ 6 V
(Gearbox & Motor)
|1600 mA||3000 RPM||4 oz-in||10:1 HPCB||10:1 HPCB dual-shaft|
|1000 RPM||9 oz-in||30:1 HPCB||30:1 HPCB dual-shaft|
|625 RPM||15 oz-in||50:1 HPCB||50:1 HPCB dual-shaft|
|400 RPM||22 oz-in||75:1 HPCB||75:1 HPCB dual-shaft|
|320 RPM||30 oz-in||100:1 HPCB||100:1 HPCB dual-shaft|
|200 RPM||40 oz-in||150:1 HPCB||150:1 HPCB dual-shaft|
|140 RPM||50 oz-in||210:1 HPCB||210:1 HPCB dual-shaft|
|120 RPM||60 oz-in||250:1 HPCB||250:1 HPCB dual-shaft|
|100 RPM||70 oz-in||298:1 HPCB||298:1 HPCB dual-shaft|
|32 RPM||125 oz-in||1000:1 HPCB||1000:1 HPCB dual-shaft|
(same specs as
|1600 mA||6000 RPM||2 oz-in||5:1 HP|
|3000 RPM||4 oz-in||10:1 HP||10:1 HP dual-shaft|
|1000 RPM||9 oz-in||30:1 HP||30:1 HP dual-shaft|
|625 RPM||15 oz-in||50:1 HP||50:1 HP dual-shaft|
|400 RPM||22 oz-in||75:1 HP||75:1 HP dual-shaft|
|320 RPM||30 oz-in||100:1 HP||100:1 HP dual-shaft|
|200 RPM||40 oz-in||150:1 HP||150:1 HP dual-shaft|
|140 RPM||50 oz-in||210:1 HP|
|120 RPM||60 oz-in||250:1 HP|
|100 RPM||70 oz-in||298:1 HP||298:1 HP dual-shaft|
|32 RPM||125 oz-in||1000:1 HP||1000:1 HP dual-shaft|
|700 mA||2200 RPM||3 oz-in||10:1 MP||10:1 MP dual-shaft|
|730 RPM||8 oz-in||30:1 MP|
|420 RPM||13 oz-in||50:1 MP|
|290 RPM||17 oz-in||75:1 MP||75:1 MP dual-shaft|
|220 RPM||19 oz-in||100:1 MP||100:1 MP dual-shaft|
|150 RPM||24 oz-in||150:1 MP|
|75 RPM||46 oz-in||298:1 MP|
|25 RPM||80 oz-in||1000:1 MP||1000:1 MP dual-shaft|
|low-power||360 mA||2500 RPM||1 oz-in||5:1|
|1300 RPM||2 oz-in||10:1|
|440 RPM||4 oz-in||30:1||30:1 dual-shaft|
|250 RPM||7 oz-in||50:1||50:1 dual-shaft|
|170 RPM||9 oz-in||75:1|
|120 RPM||12 oz-in||100:1||100:1 dual-shaft|
|85 RPM||17 oz-in||150:1|
|60 RPM||27 oz-in||210:1|
|50 RPM||32 oz-in||250:1|
|45 RPM||40 oz-in||298:1||298:1 dual-shaft|
|14 RPM||70 oz-in||1000:1||1000:1 dual-shaft|
You can see all ten of the new versions below, and if there are any versions we do not yet have that you would like to see us carry, let us know in the comments!
Chris Barlow posted this interesting write-up about how he is using the USB connection of a Mini Maestro servo controller to prototype motion control for his hexapod robot. He has been going over the build in detail on his blog, so check it out over there, and be sure to take a look at this short video below:
Forum user Ken constructed a spine-chilling Halloween project that is featured at the Cedar Gables Inn Bed and Breakfast in Napa, California. His project is based on Brandon’s Motion Tracking Skull Halloween prop, but instead of just using a head-turning skull, Ken used a full-scale skeleton body to complete the creepy look.
Motion tracking skeleton at the Cedar Gables Inn.
Just like in Brandon’s example, Ken used two Sharp GP2Y0A60SZ analog distance sensors to detect objects (or humans) and a Micro Maestro servo controller to read the output values from the sensors and control the servo that moves the head. Ken improved on Brandon’s code by returning the skeleton’s head to its starting position after a short delay so the skeleton wouldn’t stare rudely at the inn’s guests.
For more information about Ken’s Halloween project, see his forum post, and if you happen to be in the Napa Valley area this Halloween, stop by the Cedar Gables Inn and check it out in person!
In case you missed it, we have Maestros and Sharp distance sensors on sale right now as part of our Polo-BOO! Halloween Sale. The sale ends in less than two days, so if you want to try doing a project like this, now is the time to get started!
Halloween is just around the corner, but there is still time for you makers out there to build terrifying interactive props and amazing costumes, and we want to help. From now through October 21, we are having a sale on servos and servo controllers, proximity sensors, programmable microcontroller boards, power supplies, and more – all the products you might want to bring your creepy creations to life. See the sale page for more details and the full list of products.
If you need some inspiration, check out our sample Halloween projects, and as always, we would love to hear about anything cool you make with our products; we might feature it on the blog!
We are pleased to introduce our new 12 V, 2.2 A switching regulator, the inaugural member of the D24V22Fx family of step down voltage regulators. We expect to release other voltage versions next month, but we wanted to get a 12 V version out right away since we did not offer a 12 V buck regulator that could do more than 1 A. The compact regulator works with input voltages up to 36 V and can typically deliver up to a continuous 2.2 A. It offers integrated reverse voltage protection along with over-current and over-temperature shutoff, and a power-good output can be used to determine when the regulator cannot maintain its output voltage.
Unlike linear regulators which waste a lot of power and generate a lot of heat in the process, this new regulator is very efficient, which means you can get the most out of your battery life:
Until we release other voltage versions of the D24V22Fx, the closest substitutes are the similar D24V25Fx family of step-down voltage regulators:
These regulators are the same size as the D24V22F12 and they have similar current capabilities and input voltage ranges, but they do not have the same pinout and they are based on a different internal design, so there are fundamental differences in operation.
To make this possible, we updated the Windows installers for the Pololu AVR C/C++ Library to support Atmel Studio 7.0. This means that when you install the library on Windows, it will automatically copy its files into the AVR GCC toolchain inside Atmel Studio 7.0 and install project templates for the supported devices. Adding support for Atmel Studio 7.0 required us to add some code to detect its location and fix two unexpected problems. You can see the changes that were made in the libpololu-avr commit history on GitHub.
The second screen of the Pololu AVR C/C++ Library installer for Windows.
Importing an Arduino sketch in Atmel Studio 7.0
Atmel Studio 7.0 is the latest version of Atmel Studio, an integrated development environment (IDE) for AVRs from Atmel. It has an interesting new feature that allows you to create a new project from an Arduino sketch. The idea is that you could import an Arduino sketch, compile it with Atmel Studio, and then load it onto an Arduino-compatible board using a debugger from Atmel. This would allow you to step through the program one line at a time as it runs on real hardware and see what the program does at each step. It would also allow you to use the advanced code editing features of Atmel Studio. When you import a sketch into Atmel Studio 7.0, the source code of your sketch, along with the Arduino core source code and the code for any libraries you are using, gets copied into the directory for the new project.
However, the new feature only supports a certain small set of boards from Arduino and Adafruit, which means that you would have to select a board similar to your Orangutan, 3pi robot, or A-Star and then adjust the project settings (such as the F_CPU clock speed macro) to make it work. Atmel Studio does not support Arduino bootloaders, so it will not be easy to program an A-Star without getting an external programmer. Our Pololu USB AVR Programmer does not support debugging, so if that is the only programmer you have, then there is relatively little value in using Atmel Studio to program your device instead of just using the Arduino IDE. The feature does not appear to be very polished and still has bugs, which I encountered when I tried to import a sketch that has multiple .h and .cpp files.
If you want to try out the new feature, just open Atmel Studio 7.0, select File > New > Project…, and then select “Create Project from Arduino sketch”, which is a template that can be found in the “C/C++” category.
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.