Pololu Blog (Page 9)
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.
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…
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!
We love motors here at Pololu, and we are committed to offering you the best selection so that you can find just the right drive solution for your project. Our latest efforts have gone into expanding our selection of 20D gearmotors to include 12 V versions, which have approximately the same performance at 12 V as our 6 V versions do at 6 V, just with half the current draw. This in turn enables the use of lower-current (and typically lower-cost) motor drivers in applications with access to higher voltages.
Additionally, we noticed that our original 6 V versions do not last as long as we would like in some applications, so we made these new 12 V versions with long-life carbon brushes instead of precious metal brushes, and we released new versions of our 6 V motors with long-life carbon brushes as well. These versions have “CB” in their names, and they can be differentiated from versions with precious metal brushes by their copper-colored terminals.
20D mm metal gearmotor precious metal brushes (left) next to 20D 6V CB and 12V CB long-life carbon brushes.
Please note that making the brushes more robust can just move the failure point to the windings or gears if you try to push the motors too hard, but if you use them around their nominal voltages and keep the continuous load low (under around 20% of the stall torque or 1 kg-cm, whichever is lower), the carbon brushes allow the motors to last several times longer than versions with precious metal brushes.
Changing the brushes does affect the performance in ways beyond lifetime (e.g. the starting voltage is generally a little higher with the carbon brushes), so we are continuing to offer precious metal versions of our 6 V motors for now, but we might phase those out in the future. Please contact us or post a comment below if continued availability of the precious metal versions is important to you.
Currently, only the 6V versions with precious metal brushes are available with a rear motor shaft that can be used to add an encoder, like our magnetic encoder for 20D mm metal gearmotors, but the 6V CB and 12V CB motors should be available with this rear shaft option by the end of November.
With the addition of these new units, our selection of 20D gearmotors now spans nearly fifty options:
@ Rated Voltage
@ Rated Voltage
@ Rated Voltage
(Gearbox & Motor)
|1.6 A||570 RPM||26 oz-in||25:1 12V CB|
|450 RPM||33 oz-in||31:1 12V CB|
|225 RPM||58 oz-in||63:1 12V CB|
|180 RPM||75 oz-in||78:1 12V CB|
|140 RPM||85 oz-in||100:1 12V CB|
|110 RPM||110 oz-in||125:1 12V CB|
|90 RPM||130 oz-in||156:1 12V CB|
|72 RPM||160 oz-in||195:1 12V CB|
|57 RPM||200 oz-in||250:1 12V CB|
|45 RPM||250 oz-in||313:1 12V CB|
|36 RPM||290 oz-in||391:1 12V CB|
|29 RPM||350 oz-in||488:1 12V CB|
|2.9 A||590 RPM||22 oz-in||25:1 6V CB|
|470 RPM||28 oz-in||31:1 6V CB|
|230 RPM||54 oz-in||63:1 6V CB|
|190 RPM||62 oz-in||78:1 6V CB|
|150 RPM||72 oz-in||100:1 6V CB|
|120 RPM||87 oz-in||125:1 6V CB|
|93 RPM||110 oz-in||156:1 6V CB|
|75 RPM||130 oz-in||195:1 6V CB|
|60 RPM||170 oz-in||250:1 6V CB|
|46 RPM||220 oz-in||313:1 6V CB|
|37 RPM||260 oz-in||391:1 6V CB|
|30 RPM||310 oz-in||488:1 6V CB|
|2.9 A||590 RPM||22 oz-in||25:1 6V||25:1 6V dual-shaft|
|470 RPM||28 oz-in||31:1 6V||31:1 6V dual-shaft|
|230 RPM||54 oz-in||63:1 6V||63:1 6V dual-shaft|
|190 RPM||62 oz-in||78:1 6V||78:1 6V dual-shaft|
|150 RPM||72 oz-in||100:1 6V||100:1 6V dual-shaft|
|120 RPM||87 oz-in||125:1 6V||125:1 6V dual-shaft|
|93 RPM||110 oz-in||156:1 6V||156:1 6V dual-shaft|
|75 RPM||130 oz-in||195:1 6V||195:1 6V dual-shaft|
|60 RPM||170 oz-in||250:1 6V||250:1 6V dual-shaft|
|46 RPM||220 oz-in||313:1 6V||313:1 6V dual-shaft|
|37 RPM||260 oz-in||391:1 6V||391:1 6V dual-shaft|
|30 RPM||310 oz-in||488:1 6V||488:1 6V dual-shaft|
Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. In order to avoid damaging the gearbox, we recommend keeping continuously applied loads under 50 oz-in (3.5 kg*cm) for the versions with precious metal brushes and under 70 oz-in (5 kg-cm) for the versions with carbon brushes (the ones with “CB” in the name). Stalls can also result in rapid (potentially on the order of a second) thermal damage to the motor windings and brushes, especially for motors like this that can deliver a lot of power for their size; a general recommendation for brushed DC motors is to limit continuous current to approximately 25% of the stall current.
Everyone wants free shipping, right? Well, today I am happy to announce an important step in bringing free shipping to Pololu, at least for our US customers. We are beginning to offer free shipping in these two senses:
Free shipping within the United States
Some items are eligible for free shipping within the United States. If your shopping cart consists only of items eligible for free shipping, you will be presented with a “Free Shipping” shipping option during checkout. Free shipping will be shipped by a carrier and service we select, which will typically be the lowest-cost, slowest service. Currently, that would likely be First-Class Mail through the US Post Office or a ground service by FedEx, depending on the contents of the order.
Free add-on shipping within the United States
Some items are eligible for free add-on shipping for orders within the United States. These are typically very light items that should not significantly impact our shipping cost, and we pass on those savings to you. No additional shipping will be charged for these items, independent of your shipping method. Orders that consist only of free add-on shipping items will cost the minimum shipping cost for each service as the item sizes and weights will not be added to the shipping cost calculation. Orders with at least one free shipping item and the rest free add-on shipping items will have a free shipping option.
Because items with free add-on shipping will not be considered in the calculation, it is possible for the shipping method you select to be invalid because the package exceeds the limit for that method. In such cases, we will substitute a similar shipping method. For example, if you pay for First-Class Mail as your shipping method but your order actually ends up weighing more than the limit for First Class Mail, we would ship by Priority Mail.
By controlling these two aspects of free shipping on an individual product level, we can really offer free shipping, without raising prices. We are rolling this feature out with a few items we would like to promote:
Products initially eligible for free shipping and free add-on shipping:
Products initially eligible for free shipping only:
Products initially eligible for free add-on shipping only:
As we work on our system and monitor the results with these initial products, my goal is to make free shipping, or at least incrementally free shipping, available for more and more of our products. We still do not have a solution for those of you who write us angry emails about the ridiculousness of our charging $3.95 to ship a $2 part (and yes, I am aware of 39-cent listings with free shipping on AliExpress; for now, we cannot compete with them on price alone). But rest assured that since shipping is one of our biggest expenses, we will continue to work hard on keeping that cost as low as we can.
If you see a product that you feel should qualify for free shipping or free add-on shipping but does not, please contact us, and we can evaluate the product’s eligibility. I would also like to hear what you think of this approach and whether you expect it will be helpful to you.
Update (31 October 2017): We are now offering lots more free shipping.
The Boe-Bot Robot Kit is an educational kit complete with parts and a textbook for building and programming your own robot. No previous robotics, electronics, or programming experience is required; the kit does not require soldering.
Get a FREE copy of Circuit Cellar magazine’s October 2017 issue issue with your order, while supplies last. To get your free issue, enter the coupon code CIRCUIT1017 to your shopping cart, or click the link. The magazine will add 6 ounces to your order weight when calculating your shipping options.
For back issues and more information, see our free Circuit Cellar magazine offers.
Pololu customer Yvon Hache made this 3D-printed aerial photography rig that he shared in a forum post. The rig, trailing 100 feet below the kite, automatically triggers a camera to take pictures at three tilt angles and sixteen pan angles. It incorporates an ARM Cortex-M4 microcontroller from Texas Instruments (32-bit, 80 MHz, TM4C123GH6PZ), an AltIMU-10 v5, Pololu voltage regulators, and a Zigbee module for wireless remote control. Yvon uses a pair of Pololu micro metal gearmotor extended brackets per motor—one mounts the motor to the frame and the other protects the encoder assembly.
More kite rig information and pictures can be found on Yvon’s website.
Our popular premium jumper wires and wires with pre-crimped terminals are a convenient way to make quick, neat connections to 0.1″ (2.54 mm) connectors and solderless breadboards, and they are now available in shorter 1″ and 2″ lengths. Each new length is available in three gender combinations (female-female, male-female, and male-male) and seven color combinations:
- black 10-pack
- red 10-pack
- yellow 10-pack
- green 10-pack
- blue 10-pack
- white 10-pack
- multi-color 60-pack (10 each of all six colors)
Our wires with pre-crimped terminals work with our 0.1″ crimp connector housings to make custom cables with the pin arrangement of your choosing. You can easily make cable harnesses or assemblies that branch from one connector on one side to multiple connectors on the other, and you can also cut off one pre-crimped end and solder the wires directly to components to make swapping connections easy:
The premium jumper wires are just wires with pre-crimped terminals that have 1×1 crimp connector housings already installed over the crimp pins.
You can use the following selection boxes to get to a specific pack of premium jumper wires:
Alternatives available with variations in these parameter(s): gender length color
and you can use the following selection boxes to get to a specific pack of wires with pre-crimped terminals:
Alternatives available with variations in these parameter(s): gender length color
Pololu 22T Track Set – Red.
We have replaced our original Pololu track sets with new versions featuring our newer style of spoked Zumo sprockets. The sprockets are available in three colors, and like our original sets, we have two different track lengths to choose from:
- 22T tracks with black sprockets
- 22T tracks with red sprockets
- 22T tracks with white sprockets
- 30T tracks with black sprockets
- 30T tracks with red sprockets
- 30T tracks with white sprockets
Each track is made of a single piece of flexible silicone, and the drive sprockets are designed to work with 3mm D-shafts, such as those on our micro metal gearmotors and most of our mini plastic gearmotors.
Additionally, we are offering sprockets by themselves (without tracks or fasteners) for use as replacements for the black sprockets included with our Zumo robots: you can use the red sprockets to add a splash of color, and you can use the white sprockets for painting (or just leave them white!).
This summer, Jon and I participated in NASA’s nationwide Eclipse Ballooning Project with the University of Nevada. Specifically, we were members of the University of Nevada, Las Vegas (UNLV) section of Nevada’s team which also had a section from the University of Nevada Reno (UNR). Our goal was to make a payload to collect interesting video footage and scientific data, then fly that payload on a high-altitude balloon that would ascend to around 100,000 ft in the totality zone during the 2017 solar eclipse on August 21. Continued…
We are having a Labor Day sale all weekend long with site-wide discounts of up to 25%! Check out the sale page for more information. Please note that we will be closed Monday, so orders placed after 2 PM Pacific Time today (Friday, September 1) will be shipped on Tuesday, September 5.