Pololu High-Power Stepper Motor Driver 36v4 (md38a) with large stepper motor.

I am very excited to announce the release of our new High-Power Stepper Motor Driver 36v4, our most powerful stepper motor driver yet, with more than twice the current capabilities of any of our alternative drivers. This driver can deliver a continuous 4 A per phase without any heat sinks or active cooling, and up to 6 A with cooling! This means we finally have a driver capable of powering our largest stepper motors like this beefy motor with a 2.8 A current rating.

This new driver also has a wide 8 V to 50 V operating range, making it great for use in 12, 24, or 36 V systems. And though you might be thinking that your stepper motor’s voltage rating is well below that max voltage so what do you care, keep in mind that running you stepper motor at a higher voltage while actively limiting the current (as you can do with all our stepper motor drivers) allows you to achieve higher step rates than you could using the rated voltage.

Other exciting features of this driver include nine different step resolutions down to 256 microsteps, STALL and BEMF (back EMF) outputs that enable more advanced control algorithms, and highly adjustable decay parameters and modes for creating ultra-smooth motion profiles. The driver is configurable through its SPI interface, and our Arduino library and example sketches can help you get started.

As usual, we are offering an extra introductory special discount on the High-Power Stepper Motor Driver 36v4 to help share in our celebration of releasing a new product. The first hundred customers to use coupon code HPSMDINTRO can get up to three units for just $8.95 each!

Our Micro Metal Gearmotors are now available with 380:1 gearboxes, offering a new high gear ratio option between our existing 298:1 and 1000:1 versions. Unlike the 1000:1 gearmotors, which uniquely require a longer, more expensive gearbox to achieve such a big reduction, the 380:1 gearboxes fit everything in the same volume as all our lower gear ratios, so they are the same price as those lower-ratio versions and they work with all our micro metal gearmotor brackets.

What really sets these new units apart from our other gear ratios are their stainless steel gearbox plates, which are more durable than the ubiquitous brass ones, especially in applications with non-negligible radial loads. They also look way cooler! Continued…

We have filled out our line of 5:1 Glideforce Light-Duty Linear Actuators to include all of Concentric’s available lengths by adding 2″, 6″, 8″, and 10″ versions, with and without feedback, to our existing 4″ and 12″ options. The low gear ratio makes these our fastest (but weakest) linear actuators, capable of lifting up to a few dozen pounds at speeds up to 1.7″ per second (44 mm/s) at 12 V. For stronger but slower options, we have versions available with a 10:1 gear ratio or 20:1 gear ratio.

This brings our total selection of light-duty actuators to 36 options:

Actuator Type	Max Dynamic Load	No-Load Speed @ 12 V	Max-Load Speed @ 12 V	Current Draw @ 12 V	Nominal Stroke Length	With Feedback	Without Feedback
Light-Duty (LD) 5:1	15 kgf [34 lbs]	4.4 cm/s [1.7″/s]	3.6 cm/s [1.4″/s]	1.2 A – 3.2 A	2″	LACT2P-12V-05	LACT2-12V-05
					4″	LACT4P-12V-05	LACT4-12V-05
					6″	LACT6P-12V-05	LACT6-12V-05
					8″	LACT8P-12V-05	LACT8-12V-05
					10″	LACT10P-12V-05	LACT10-12V-05
					12″	LACT12P-12V-05	LACT12-12V-05
Light-Duty (LD) 10:1	25 kgf [55 lbs]	2.8 cm/s [1.1″/s]	2.3 cm/s [0.9″/s]	1.2 A – 3.2 A	2″	LACT2P-12V-10	LACT2-12V-10
					4″	LACT4P-12V-10	LACT4-12V-10
					6″	LACT6P-12V-10	LACT6-12V-10
					8″	LACT8P-12V-10	LACT8-12V-10
					10″	LACT10P-12V-10	LACT10-12V-10
					12″	LACT12P-12V-10	LACT12-12V-10
Light-Duty (LD) 20:1	50 kgf [110 lbs]	1.5 cm/s [0.57″/s]	1.2 cm/s [0.48″/s]	1.2 A – 3.2 A	2″	LACT2P-12V-20	LACT2-12V-20
					4″	LACT4P-12V-20	LACT4-12V-20
					6″	LACT6P-12V-20	LACT6-12V-20
					8″	LACT8P-12V-20	LACT8-12V-20
					10″	LACT10P-12V-20	LACT10-12V-20
					12″	LACT12P-12V-20	LACT12-12V-20

We now have new current sensors based on Allegro’s ACS724, the successor to the ACS714 that we have been using for many years. The ACS724 offers a number of exciting improvements over the ACS714, including more current range options (up to ±50 A!), over twice the sensitivity for the ±5 A version, a higher bandwidth for faster response times, and differential Hall sensing for substantially reduced interference from ambient magnetic fields. In quick tests, we saw a variation of around 1% of the full range just from changing the orientation of the ACS714 in space (because of the Earth’s magnetic field), while the ACS724 output stayed steady regardless of orientation. We also tried bringing a small magnet close to each sensor, and its effect on the output was many times smaller on the ACS724.

These bidirectional and unidirectional current sensors are a simple way to gain fundamental insight into the performance of your system. You can use them for closed-loop torque control of actuators, tracking power consumption over time, or even as inexpensive current probes for an oscilloscope. They output an analog voltage that varies linearly with the current passing through them, and because they use the Hall effect to measure the current, they offer full electrical isolation of the current path from the sensor’s electronics. This method of sensing means the sensor can be inserted anywhere into the current path, including on the high side, and because their current path resistance is on the order of 1 mΩ or less, they have minimal effect on the rest of the system.

Five different current ranges are available:

• ACS724 Current Sensor Carrier -5A to +5A
• ACS724 Current Sensor Carrier -20A to +20A
• ACS724 Current Sensor Carrier -50A to +50A
• ACS724 Current Sensor Carrier 0A to 10A
• ACS724 Current Sensor Carrier 0A to 30A

Together with the Broadcom ACHS-712x current sensors we released last month, this brings our full current sensor lineup to thirteen sensors:

Introductory special

As usual, we are offering an extra introductory special discount on the ACS724 current sensor carriers, to help share in our celebration of releasing a new product. The first hundred customers to use coupon code ACS724INTRO can get up to five units for just $5.55 each!

Silicone Tire Pair for 80×10mm/90×10mm (left) and 60×8mm/70×8mm (right) Pololu Wheels.

We have recently had several requests for just the tires from our largest Pololu wheels, so here they are! The silicone tires are available in two sizes, with the smaller tire working with our 60×8mm and 70×8mm wheels and the larger tire working with our 80×10mm and 90×10mm wheels. The tires are intended primarily as replacement parts for our wheels, but they can also be used as nicer tires for other similarly sized wheels, such as the 2-5/8″ plastic wheels for Futaba servos.

DB15 Screw Terminal Adapter for MCP23X/26X Advanced Motor Controllers with included hardware.

DB15 screw terminal adapter mated to an MCP266 Advanced Motor Controller.

We are now carrying a DB15 Screw Terminal Adapter for MCP23X/26X Advanced Motor Controllers. The adapter breaks out connections from the DB15 connector to a set of screw terminals, making accessing those pins easier during prototyping. It is designed specifically to work with the MCP Advanced Motor Controllers that feature a DB15 connector: the MCP233, MCP236, MCP263, and MCP266. However, it could also be used as a generic breakout board for other hardware that uses the same connector, like old computer joysticks or MIDI devices (where it is called a game port).

I am happy to announce the release of our newest regulators, the D36V28Fx family of step-down voltage regulators. These regulators support a wide input voltage range (up to 50 V!) and can deliver up to 4 A, making them well suited for use with power-hungry processors like the Raspberry Pi and projects involving servos or small motors.

Step-Down Voltage Regulator D36V28Fx, assembled on breadboard.

Step-Down Voltage Regulator D36V28Fx, bottom view with dimensions.

The family consists of six fixed output voltage versions between 3.3 V and 12 V:

• D36V28F3: Fixed 3.3V output
• D36V28F5: Fixed 5V output
• D36V28F6: Fixed 6V output
• D36V28F7: Fixed 7.5V output
• D36V28F9: Fixed 9V output
• D36V28F12: Fixed 12V output

And since we make these ourselves here in Las Vegas, we can also quickly make versions with custom output voltages; please contact us us for more information.

Comparison to the D24V22Fx step-down regulator family

Top view of D36V28Fx step-down voltage regulator.

Top view of D24V22Fx step-down voltage regulator.

The D36V28Fx family now becomes our recommended alternative to the slightly smaller D24V22Fx if you need a little more power or operation above 36 V:

Comparison of the maximum continuous current of Step-Down Voltage Regulators D36V28Fx and D24V22Fx.

The D24V22Fx still outperforms the D36V28Fx when it comes to dropout voltage and quiescent current:

Comparison of the dropout voltage of Step-Down Voltage Regulators D36V28Fx and D24V22Fx.

Comparison of the quiescent current of Step-Down Voltage Regulators D36V28Fx and D24V22Fx.

Introductory special

As usual, we are offering an extra introductory special discount on these new regulators, to help share in our celebration of releasing a new product. The first hundred customers to use coupon code D36V28XINTRO can get up to three units for just $7.77 each!

We are excited to offer new carriers for Hall effect-based linear current sensors from Broadcom. These easy-to-use bidirectional current sensors are available in three current range options:

• ACHS-7121 Current Sensor Carrier -10A to +10A
• ACHS-7122 Current Sensor Carrier -20A to +20A
• ACHS-7123 Current Sensor Carrier -30A to +30A

The ±10A and ±30A version have the same output sensitivity as our older ±5A and ±30A Allegro ACS714 Hall effect-based linear current sensor, respectively, so they should work as a drop-in replacement in many applications.

Introductory special

As usual, we are offering an extra introductory special discount on the ACHS-712x current sensor carriers, to help share in our celebration of releasing a new product. The first hundred customers to use coupon code ACHSINTRO can get up to five units for just $3 each!

RoboClaw Case with Fan enclosing a RoboClaw (not included).

RoboClaw Case with Fan, open with RoboClaw (not included) mounted inside.

With this new RoboClaw case, our selection of RoboClaw products just got even cooler – literally! In addition to protecting the motor controller, this case also has an integrated fan, which will allow an enclosed RoboClaw to deliver higher continuous currents and sustain peak currents longer. The case works with 2x15A, 2x30A, 2x45A, and ST 2x45A RoboClaw motor controllers and features cutouts for accessing the motor outputs and the various control input header pins.

We have updated our A-Star 32U4 Prime LV with a new regulator that offers a wider operating voltage range and increased current capabilities. For those of you not already familiar with our A-Star 32U4 Primes, they are a series of ATmega32U4-based, USB-programmable controllers with integrated regulators that offer operating voltage ranges not available on typical Arduino-compatible products; this new “LV” variant features an improved buck-boost converter that enables efficient operation from 2 V to 16 V power supplies (Note: it requires an input voltage of at least 3 V to start, but it can operate down to 2 V after startup). The A-Star Primes are arranged in the common Arduino form factor exemplified by the Uno R3 and the Leonardo, so they are compatible with many Arduino shields, including all of the Arduino shields we carry.

In addition to the increased input voltage range for the new A-Star Prime LV, the new regulator also provides more current. The graph below shows the current available on the new LV (ac03e) in blue compared to the old LV (ac03b) in purple. It is important to note that to use the full current available on the new A-Star Prime LV, you must connect to the VREG pin on the board and not the 5V ouput pin. The 5V output pin is limited to about 1.9 A because of the TPS2113A power multiplexer that makes up the board’s power selection circuit (a feature that sets the A-Star Primes apart from competing products). The power multiplexer decides whether the board’s 5 V supply is sourced from USB or an external supply via the regulator, allowing both sources to be connected at the same time and enabling the A-Star to safely and seamlessly transition between them. The multiplexer is configured to select external power unless the regulator output falls below about 4.5 V. If this happens, it will select the higher of the two sources, which will typically be the USB 5 V bus voltage if the A-Star is connected to USB. More information about the multiplexer can be found in this section of the A-Star 32U4 user’s guide under the Power heading.

Typical maximum output current of the 5 V regulators on the A-Star 32U4 Primes.

Power multiplexing circuit for the A-Star Prime LV.

The original version of the A-Star Prime LV, which operates from 2.7 V to 11.8 V, is now on clearance for 40% off! If you don’t need the increased output current and wider voltage range the new board offers, the previous version is still a great programmable controller to consider. Both the new and original A-Star Prime LVs come in multiple configurations. The complete selection of both versions can be found in the related products list below.