Over the next few days, we’re welcoming summer by discounting all active Pololu-brand products, which is almost everything we make. If you’re about to have a lot of free time on your hands, why not spend some of it building a robot? And if you’re going to be as busy as ever this summer, why not unwind by building a robot?

Check out the sale page for details!

Please note that we will be closed on Monday for Memorial Day, so orders will not ship until Tuesday, May 29.

Arduino Day is this Saturday, May 12, and in celebration, we are having a big sale on many of our Arduino-related products, including Pololu-made Arduino shields and Arduino-compatible A-Stars and robots. For those who aren’t necessarily enamored with the Arduino environment but are excited about AVR microcontrollers, you can program these products from AVR Studio or other environments using our AVR Programmer, which is also on sale. And because of the awesome way we don’t include motors with the Balboa or Zumo Robot kits, we are also putting those on sale so you can get all the parts for your robots at a discount (we’ll let it slide if you just want to stock up on motors independent of any kind of Arduino application)!

The sale has already started, and it runs through Monday, May 14.

After spending many months conducting thousands of motor tests, we are excited to finally publish performance graphs for our micro metal gearmotors (5MB pdf). In some sense, this datasheet is the culmination of a decade of work to improve our processes and better characterize our gearmotors, and we have come a long way since those early tests clamping motors in vises and making them lift ever heavier bags of steel bearings. Here is one of the setups we are using now:

Micro Metal Gearmotor undergoing dynamic performance testing.

The key thing is to be able to apply a measurable, variable load while the motor is spinning, which we do via an electromagnetic brake coupled to a torque meter. A combination of programs running on an A-Star 32U4 Prime test controller and a PC automatically sweep the load through a sequence of points while measuring parameters such as speed, current, and torque (plus internal test rig currents, voltages, etc).

Micro Metal Gearmotor performance test setup.

These performance characterizations are the latest example of our continued commitment to being the best source for this popular form factor of gearmotor. You might see similar-looking motors elsewhere, but no one comes close to our offering, from the quality of the gears to our exclusive long-life carbon brush options to the overall breadth of our selection (over 100 versions!), all in stock for shipment the day you order.

Please note that we are still in the process of updating the specifications on our website to match new, more accurate data from the performance graphs, so if you notice discrepancies between what is in the datasheet and what is on the product page, go with the datasheet.

If you have any questions or feedback about these graphs or if there is additional information you would like to see available for our motors, please feel free to contact us (or just leave a comment below). And if you are wondering about graphs for our larger gearmotors, don’t worry, those are coming! (If you need something before those datasheets are done, just let us know and we might be able to get you preliminary data for a particular gearmotor.)

Performance summary table from Micro Metal Geamotor datasheet.

We are now carrying Ion Motion Control’s line of single-channel RoboClaws, the Solo 30A and Solo 60A. These versatile, high-power motor controllers have nearly all the same features and performance capabilities as their dual-channel 2×30A and 2×60A counterparts, just with one fewer motor channel. Just like the rest of the RoboClaw family, the Solos support a variety of interfaces, including USB serial, TTL serial, RC hobby servo pulses, and analog voltages, and integrated quadrature decoders enable closed-loop position or velocity control.

Unlike our selection of dual-channel RoboClaws, the Solos also feature a rugged, all-metal case that protects the driver while simultaneously serving as a heat sink, and they have four 12 AWG unterminated leads for supplying power and connecting a motor.

The following table shows our full updated offering of RoboClaw motor controllers:

	Solo 30A	Solo 60A	2x7A	2x15A	2x30A	2x45A ST 2x45A	2x60A
Motor channels:	1		2
Operating voltage:	6 V to 34 V		6 V to 34 V
Continuous output current:	30 A	60 A	7.5 A	15 A	30 A	45 A	60 A
Peak output current:	60 A	120 A	15 A	30 A	60 A	60 A	120 A
5V BEC max current:	1.2 A		1.2 A (V5B or later)	3 A
Size	60 × 32.5 × 23.5 mm		48 × 42 × 17 mm	74 × 52 × 17 mm			100 × 86 × 25 mm
Weight:	130 g		18 g	60 g			295 g
Price:	$89.95	$119.95	$114.95	$129.95	$169.95	$191.95	$199.95

Related products

	RoboClaw Solo 30A Motor Controller
	RoboClaw Solo 60A Motor Controller

We are excited to expand our colorful selection of stepper motor drivers with carrier boards for the brand new MPS MP6500 stepper motor driver!

Monolithic Power Systems’ MP6500 can drive a bipolar stepper motor from a 4.5 V to 35 V supply with up to 1/8-step microstepping. On our four-layer, 2 oz copper carrier boards, the MP6500 can deliver up to approximately 1.8 A per phase continuously without a heat sink or forced air flow, making this new module the highest-current stepper motor driver we carry among all the ones that share this form factor.

14 March 2018 Update: After further testing of more units, our initial characterization of the maximum continuous current capability was too high, so we have lowered it to 1.5 A. Please keep in mind that the exact maximum current you can get out of the driver at a given temperature will depend on your supply voltage and stepper motor characteristics.

Unlike most other stepper motor drivers, the MP6500 features internal current sensing, which allows it to measure the motor’s coil current even during the off period of the PWM cycle. Combined with its automatic decay selection, this allows it to regulate the current especially accurately to produce smoother motion and higher speeds, as shown in the below oscilloscope capture from the MPS application note AN120 (1MB pdf).

Compare this with waveforms from a stepper driver that uses a more typical method of peak current control:

In addition to a version with potentiometer current control like most of our other stepper motor drivers, we also offer the MP6500 on a board with digital current control. This second version enables a microcontroller to dynamically set the current limit in steps of 0.5 A (up to a maximum of 2 A) by simply driving one or two inputs low. Alternatively, supplying an analog voltage or PWM signal allows finer control of the limit within the 0 to 2 A range.

Current limit vs. potentiometer setting for the MP6500 Stepper Motor Driver Carrier, Potentiometer Current Control.

Current limit vs. PWM duty cycle for the MP6500 Stepper Motor Driver Carrier, Digital Current Control.

Introductory special: just $2.97 each! Must use coupon code MP6500INTRO, limited to first 200 customers, limit 5 per customer.

Related products

	MP6500 Stepper Motor Driver Carrier, Potentiometer Current Control
	MP6500 Stepper Motor Driver Carrier, Digital Current Control

We have expanded our selection of Glideforce linear actuators from Concentric International to include their industrial-duty and medium duty series as steps up in power from their light-duty series that we have been offering for many years now.

The medium-duty actuators are available in five different stroke lengths ranging from 4″ to 12″ and with or without feedback potentiometers, and they have a dynamic load rating of 225 lb, which means they can handle twice the load of their light-duty counterparts:

Glideforce Medium-Duty (MD) series of linear actuators with feedback.

Glideforce Medium-Duty (MD) series of linear actuators without feedback.

The industrial-duty actuators are real monsters compared to the medium-duty and light-duty units. The versions with an acme screw drive can handle dynamic loads up to 550 lb, and the versions with a ball screw drive (which is much more efficient than an acme screw) can handle dynamic loads up to a 1000 lb. Each drive option is available in six different stroke lengths ranging from 4″ to 24″ and with or without feedback potentiometers:

The following lets you compare all of our Glideforce linear actuator options:

Note that we are currently out of stock of many of the industrial-duty versions, but we will be getting more as Concentric makes them available. For units where the expected lead time is several months, we have disabled backorders; please contact us if you are interested in placing an order now for one of those units.

To see all of our linear actuators, visit our linear actuator category.

We will be closed for Christmas on Monday, December 25 and for New Year’s Day on Monday, January 1. Orders placed after 2 PM Pacific Time on December 22nd or 29th will be shipped on the following Tuesdays.

And last call for our Christmas sale — only about 15 hours to go!

Merry Christmas and happy New Year!

If you missed our Black Friday sale or realize you didn’t quite get everything you wanted, don’t fret: we have all active Pololu-brand and PCX products on sale for 12% off, and we are offering 20% off twelve broad categories of our products. The sale runs through noon PST on Friday, December 22, but be careful to order early for delivery before Christmas. Save on your Christmas shopping, or stock up now on robot parts for the new year. Check out the sale page for all the discounts and coupon codes. Merry Christmas!

20D mm metal gearmotor CB with long-life carbon brushes.

20D mm metal gearmotor CB with long-life carbon brushes and an extended motor shaft.

Magnetic Encoder Kit for 20D mm Metal Gearmotors assembled on a 20D mm metal gearmotor with extended motor shaft.

Last month when we introduced versions of our 20D gearmotors with long-life carbon brushes, we mentioned units with extended motor shafts were in the works. Well, I’m happy to announce that option is now available for both the 12V CB and 6V CB 20D gearmotors, making it possible to use them with encoders like our magnetic encoder kit. The following table shows our full selection of 20D gearmotors, which has now grown to 72 options:

Rated Voltage	Brush 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	long-life carbon (CB)	1.6 A	570 RPM	26 oz-in	25:1 12V CB	25:1 12V CB dual shaft
			450 RPM	33 oz-in	31:1 12V CB	31:1 12V CB dual shaft
			225 RPM	58 oz-in	63:1 12V CB	63:1 12V CB dual shaft
			180 RPM	75 oz-in	78:1 12V CB	78:1 12V CB dual shaft
			140 RPM	85 oz-in	100:1 12V CB	100:1 12V CB dual shaft
			110 RPM	110 oz-in	125:1 12V CB	125:1 12V CB dual shaft
			90 RPM	130 oz-in	156:1 12V CB	156:1 12V CB dual shaft
			72 RPM	160 oz-in	195:1 12V CB	195:1 12V CB dual shaft
			57 RPM	200 oz-in	250:1 12V CB	250:1 12V CB dual shaft
			45 RPM	250 oz-in	313:1 12V CB	313:1 12V CB dual shaft
			36 RPM	290 oz-in	391:1 12V CB	391:1 12V CB dual shaft
			29 RPM	350 oz-in	488:1 12V CB	488:1 12V CB dual shaft
6 V	long-life carbon (CB)	2.9 A	590 RPM	22 oz-in	25:1 6V CB	25:1 6V CB dual shaft
			470 RPM	28 oz-in	31:1 6V CB	31:1 6V CB dual shaft
			230 RPM	54 oz-in	63:1 6V CB	63:1 6V CB dual shaft
			190 RPM	62 oz-in	78:1 6V CB	78:1 6V CB dual shaft
			150 RPM	72 oz-in	100:1 6V CB	100:1 6V CB dual shaft
			120 RPM	87 oz-in	125:1 6V CB	125:1 6V CB dual shaft
			93 RPM	110 oz-in	156:1 6V CB	156:1 6V CB dual shaft
			75 RPM	130 oz-in	195:1 6V CB	195:1 6V CB dual shaft
			60 RPM	170 oz-in	250:1 6V CB	250:1 6V CB dual shaft
			46 RPM	220 oz-in	313:1 6V CB	313:1 6V CB dual shaft
			37 RPM	260 oz-in	391:1 6V CB	391:1 6V CB dual shaft
			30 RPM	310 oz-in	488:1 6V CB	488:1 6V CB dual shaft
6 V	precious metal	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.

Related products

Magnetic Encoder Pair Kit for 20D mm Metal Gearmotors, 20 CPR, 2.7-18V

Our Black Friday/Cyber Monday Sale is nearing the halfway point; thank you to all of those who have already ordered! Today’s doorbusters are gone, but the rest of the daily specials are still active, and a lot more great deals are still coming your way, including the weekend deals we just released. We’re not doing any doorbusters Saturday and Sunday, just lots of extra discounts on big categories, so take your time looking around.

The weekend deals include two items we have never had on sale before: smart servos from XYZrobot and a 6DOF robot arm based on those servos. We recently released an Arduino library for the A1-16 smart servos and arm, making them especially easy to expand beyond their preconfigured sequences for use in your own advanced projects.

Our doorbusters will return starting at 6 AM on Cyber Monday, and rumor has it that might be a prime opportunity to snag one or two of our new Balboa balancing robots!

By the way, our friends at Adafruit are having their own Black Friday sale this weekend, with 15% off their entire catalog and 20% off their Feathers and accessories, plus free items for orders over certain amounts. You can find all the details on the Adafruit blog.