Pololu Blog

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.

Popular tags: community projects new products raspberry pi arduino more…

New product: Pololu 400-Point Breadboard with Mounting Holes

Posted by Emily on 1 November 2019
Tags: new products

What’s this? A 400-Point breadboard with mounting holes! We know you’ve been waiting for this your whole life.

Okay, maybe not. But hey, mounting holes are awesome, and now you can pick up some of our new 400-point breadboards and mount them all over the place!

This 3.2″ × 2.1″ breadboard is fairly standard in many ways. It has four bus lines spanning the length of the board and 30 rows of pins, enough for up to four 14-pin DIP ICs or three 16-pin DIP ICs. The rows and columns of tie points are conveniently labeled, multiple units can be connected for larger projects, and it has an adhesive backing for those of you who like sticking breadboards on things.

But this breadboard is also a little special. It has eight mounting holes for M2 or #2 screws spaced evenly down the center on a 1 cm pitch. Now you can do stuff like mount your breadboard to a Romi Chassis (or any robot chassis) with some standoffs like this:

Wow! So convenient! And they’re just $2.49 each! But, even better, we’ve got a special discounted price for the first hundred customers. Get up to 10 boards at just $1.75 each using coupon code 400PTBBINTRO!

New products: Magnetic Encoder Pair Kit with JST SH-type Connectors for Micro Metal Gearmotors

Posted by Patrick on 23 October 2019
Tags: new products

Everyone wants encoders on their motors, but not everyone wants to solder a bunch of wires to a tiny encoder board. That is why I am excited to announce that we are now offering two new versions of magnetic encoders for Micro Metal Gearmotors that feature JST SH-type connectors:

These encoders are easier to get up and running than our previous design that requires soldering to through-holes with a 2 mm pitch. With these new encoders, you just have to solder the board to the two motor tabs (sorry, that part is not going away yet), put the magnetic disc on the backshaft, and plug in your cable (available separately in a variety of lengths)!

We think that the “micro” aspect of our Micro Metal Gearmotors is one of their coolest features since their small size make them useful in a wide array of projects. We designed these encoders with this in mind, making them within the profile of the gearmotor on three sides (the side with the connector extends a few millimeters past the motor). Since everyone’s constraints are different, we decided to make two encoder versions, one with a top-entry connector that lets the cable come straight out of the back, and one with a side-entry connector for applications where there isn’t much space past the rear of the motor. We are also continuing to offer encoder boards with through-holes, which allow wires to be soldered to the board for especially compact installations.

Remember that you will also need 6-pin female JST SH-style cables to use our new encoders. We are offering those cables in three lengths: 12 cm, 30 cm, and 75 cm.

The ends of our cables are unterminated so you can decide how you want to connect them in your project (solder, crimp connectors, terminal blocks, etc.).

Introductory special

In case you are not as excited as I am yet, our intro special might help. Right now, you can get up to five of our new encoder pair kits for just $4.95 each using the coupon code MMGMENCINTRO! (Click to add the coupon code to your cart.) But you better hurry, this offer is limited to the first hundred customers to use the coupon code.

Polo-BOO! Halloween Sale

Posted by Emily on 4 October 2019


Looking to make an awesome Halloween costume or impressive yard display? Well, we want to help, so we’re having a sale through Wednesday, October 23 on hundreds of items you can use to make things that will impress or terrify your friends and neighbors! Visit the sale page for more information, and if you are in need of some inspiration, check out our Halloween-tagged blog posts for some sample projects.

By the way, we’d love to see more about the amazing things you all are building with our products, so please don’t hesitate to share them with us.

New product: Toshiba TB67S128FTG stepper driver carrier

Posted by Ben on 26 September 2019
Tags: new products

Our wide selection of stepper motor drivers has grown once again, this time with the addition of a full breakout board for Toshiba’s TB67S128FTG. The TB67S128FTG has many of the same great innovative features as the TB67S2x9FTG carriers we released last year, including Active Gain Control (AGC) for automatically reducing the current when full torque is not needed and Advanced Dynamic Mixed Decay (ADMD) for smoother, more even microsteps. On top of that, it adds features such as microstepping down to 1/128th-step and an optional serial interface. The driver offers a wide operating voltage range of 6.5 V to 44 V, and it can deliver 2.1 A per phase continuous (5 A peak) on our carrier board without any heat sink or forced air flow, making it our highest-current integrated driver (bested only by our discrete MOSFET High-Power Stepper Motor Driver 36v4).

These stepper motor driver carriers first debuted at Toshiba’s booth at Maker Faire Tokyo in August, and now that we finally have the drivers in volume, we are able to offer them to you! All of the driver’s control pins and outputs are available, so it can function as a complete evaluation board for the TB67128FTG, yet it is compact enough to integrate into actual projects without taking up an excessive amount of space:

TB67S128FTG Stepper Motor Driver Carrier, top view with labeled pinout.

Introductory special

As with all of our new product announcements, we are offering an introductory discount to make it extra easy to try out this new driver. Be among the first 100 customers to use coupon code TB67S128INTRO (click to add the coupon code to your cart) and up to three units for just $7.95 each.

New products: ACHS-7124/7125 current sensor carriers

Posted by Emily on 26 September 2019
Tags: new products

We have expanded our line of Hall effect-based linear current sensors from Broadcom to include ±40 A and ±50 A versions. These easy-to-use bidirectional current sensors are now available in five current range options:

With these additions, our full line of current sensors now includes 15 options with current and sensitivity ratings ranging from ±5 A with 400 mV/A sensitivity to ±75 A with 28 mV/A sensitivity. The following table shows all of current sensor options:


ACS709 Current
Sensor Carrier

ACS711EX Current
Sensor Carriers

ACS714 Current
Sensor Carriers

ACS724 Current
Sensor Carriers

ACHS-712x Current
Sensor Carriers
Sensor IC: ACS709 ACS711EX ACS714 ACS724 ACHS-712x
Current range / sensitivity(1): ±75 A / 28 mV/A ±15.5 A / 136 mV/A
±31 A / 68 mV/A
±5 A / 185 mV/A
±30 A / 66 mV/A
0–⁠10 A / 400 mv/A
0–⁠30 A / 133 mV/A
±5 A / 400 mV/A
±20 A / 100 mV/A
±50 A / 40 mV/A
±10 A / 185 mV/A
±20 A / 100 mV/A
±30 A / 66 mV/A
±40 A / 50 mV/A
±50 A / 40 mV/A
Path resistance: 1.1 mΩ 0.6 mΩ 1.2 mΩ 1.2 mΩ 0.7 mΩ
Bandwidth 120 kHz 100 kHz 80 kHz 120 kHz 80 kHz
Vcc range:(1) 3 V–5.5 V 3 V–5.5 V 4.5 V–5.5 V 4.5 V–5.5 V 4.5 V–5.5 V
Size: 0.82″ × 0.9″ 0.7″ × 0.8″ 0.7″ × 0.8″ 0.7″ × 0.8″ 0.7″ × 0.8″
Special features: configurable
over-current threshold,
low-voltage operation,
high bandwidth
over-current fault pin,
low-voltage operation
Differential Hall sensing
rejects common-mode fields,
high bandwidth
1-piece price: $9.95 $3.25 $9.95 $9.95 $4.95
1 Sensitivity based on when Vcc is 5V.

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!

New product: Tic 36v4 USB Multi-Interface High-Power Stepper Motor Controller

Posted by Ben on 25 September 2019
Tags: new products tic

I am pleased to announce the release of the Tic 36v4 USB Multi-Interface High-Power Stepper Motor Controller, the fifth model in our line of Tic Stepper Motor Controllers. The Tic 36v4 features a discrete MOSFET stepper motor driver that can deliver up to approximately 4 A per phase, without a heat sink or forced air flow, over a broad 8 V to 50 V operating range. With the ability to provide more than twice as much current as any of our previous stepper motor controllers, this is our highest-power Tic yet, and the first that can drive the most demanding stepper motors we carry (#1474 and #1478) with their full rated current (2.8 A).

Tic 36v4 USB Multi-Interface High-Power Stepper Motor Controller controlling a #1478 stepper motor from USB.

The Tic 36v4 supports microstepping resolutions down 1/256 step, which is 8 times smaller than any previous Tic model. These new, finer microstep resolutions make it increasingly important to be able to take steps at a high speed since with microsteps that small, it takes up to 51,200 of them to complete one revolution on standard stepper motors with 200 full steps per revolution. The Tic firmware takes care of that for you: it is designed to be able to produce up to 50,000 steps per second, meaning that you can get 58 RPM out of most of our stepper motors even when using 1/256 step mode. Every power of two step mode between full stepping and 1/256 is supported, allowing you to choose the right trade-off between speed and resolution.

An oscilloscope capture showing the current through one coil of a stepper motor as the Tic 36v4 takes 25600 microsteps per second in 1/256 step mode.

By default, the Tic 36v4 uses an automatic mixed decay mode for current regulation. In this mode, it dynamically selects between fast or slow decay based on the actual coil current, allowing it to achieve extremely smooth stepping in most applications without a lot of manual tuning—especially at high microstepping resolutions. (Isn’t that a nice sine wave in the picture above?)

However, if you want more control, this Tic also gives you the option to select a fixed decay mode and adjust several timing parameters to fine-tune the current decay behavior. This can be easily done with the Tic’s free graphical configuration software.

The decay mode settings for the Tic 36v4 in the Tic Control Center software.

Like the other members of the Tic family, the Tic 36v4 makes basic speed or position control of a stepper motor easy, with lots of configurable parameters (e.g. max speed and acceleration) and support for six high-level control interfaces:

  • USB for direct connection to a computer
  • TTL serial operating at 5 V for use with a microcontroller
  • I²C for use with a microcontroller
  • RC hobby servo pulses for use in an RC system
  • Analog voltage for use with a potentiometer or analog joystick
  • Quadrature encoder input for use with a rotary encoder dial, allowing full rotation without limits (not for position feedback)

This video gives a brief demonstration of these interfaces in action:


The Tic 36v4 is available with connectors soldered in or without connectors soldered in. If you do not need the high-level interfaces provided by the Tic, we also offer the Pololu High-Power Stepper Motor Driver 36v4.

Here is a handy comparison chart with all five Tic stepper motor controllers:


Tic T500

Tic T834

Tic T825

Tic T249

Tic 36v4
Operating voltage range: 4.5 V to 35 V(1) 2.5 V to 10.8 V 8.5 V to 45 V(1) 10 V to 47 V(1) 8 V to 50 V(1)
Max continuous current per phase
(no additional cooling):
1.5 A 1.5 A 1.5 A 1.8 A 4 A
Peak current per phase
(additional cooling required):
2.5 A 2 A 2.5 A 4.5 A 6 A
Microstep resolutions: full
half
1/4
1/8
full
half
1/4
1/8
1/16
1/32
full
half
1/4
1/8
1/16
1/32
full
half
1/4
1/8
1/16
1/32
full
half
1/4
1/8
1/16
1/32
1/64
1/128
1/256
Automatic decay selection: Yes Yes Yes
Automatic gain control (AGC): Yes
Driver IC: MP6500 DRV8834 DRV8825 TB67S249FTG discrete MOSFETs
Price (connectors not soldered): $19.95 $29.95 $29.95 $39.95 $49.95
Price (connectors soldered): $21.95 $31.95 $31.95 $41.95 $51.95

1 See product pages and user’s guide for operating voltage limitations.

Introductory special

As usual, we are offering an extra introductory special discount on the Tic 36v4, to help share in our celebration of releasing a new product. The first hundred customers to use coupon code TIC36V4INTRO can get up to five units for just $24.95! And we’ll even cover the shipping in the US!

37D gearmotors: helical pinion gear, new 150:1 gear ratio, and performance graphs

Posted by Emily on 3 September 2019
Tags: motors

We have some big announcements related to our 37D Metal Gearmotors to share! First, we now have new versions of our 37D gearmotors that feature helical pinion gears and first mating gears as seen in the photo on the left above. The helical gears help reduce vibrations, making the gearbox a little quieter and more efficient than the original versions that used all spur gears. The performance is otherwise unchanged, and the dimensions are the same, so the new versions with helical pinion gears can be used as direct replacements for the original units. We are using new product numbers for the new versions so you can know exactly which one you are getting, and the product numbers for the original spur versions are being phased out. The following table shows all of the new helical-pinion versions:

Rated
Voltage
Stall
Current
No-Load
Current
Gear Ratio No-Load Speed
(RPM)
Extrapolated
Stall Torque
Max Power
(W)


Without Encoder


With Encoder
(kg ⋅ cm) (oz ⋅ in)
12 V 5.5 A 0.15 A 1:1 (no gearbox) 10,000 0.5 7 item #4750
19:1 540 8.5 120 12 item #4741 item #4751
30:1 330 14 190 12 item #4742 item #4752
50:1 200 21 290 10 item #4743 item #4753
70:1 150 27 380 10 item #4744 item #4754
100:1 100 34 470 8 item #4745 item #4755
131:1 76 45 630 6 item #4746 item #4756
150:1 67 49 680 6 item #2829 item #2828

We have also expanded the 37D gearmotor line by adding a new 150:1 gear ratio, which becomes our new highest gear ratio offering for this line of gearmotors. This version has an extrapolated (i.e. theoretical) stall torque of 49 kg⋅cm (680 oz⋅in), but please keep in mind that the point of high gear ratios like this is not to allow for more total torque. Rather, they enable slower speeds and draw less current than lower gear ratios for the same loads. For all of our 37D gearmotors, we recommend keeping continuously applied loads under 10 kg⋅cm (150 oz⋅in) and instantaneous torques under 25 kg⋅cm (350 oz⋅in).

Finally, we now have published performance graphs (1MB pdf) for our 37D gearmotors, just like the ones we previously released for our Micro Metal Gearmotors and our 20D Gearmotors! Each chart is based on hundreds of individual measurements that reveal how the speed, current, power, and efficiency of that particular gearmotor version depend on the applied load (i.e. torque).

37D mm metal gearmotor undergoing dynamic performance testing.

These characterizations are yet another way we set our gearmotors apart from the many similar-looking alternatives out there. When you get your gearmotors from us, you know exactly what kind of performance to expect, and because we make and test them ourselves, you can count on getting that same performance batch after batch after batch.

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 25D 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 37D mm Metal Geamotor datasheet.

Labor Day Sale 2019

Posted by Emily on 29 August 2019


We are having a Labor Day sale through Tuesday, September 3! Check out the sale page for more information. Please note that we will be closed Monday, September 2, so orders placed after 2 PM Pacific Time Friday, August 30th will be shipped on Tuesday, September 3.

Ham radio antenna rotor control using a Tic Stepper Motor Controller

Posted by Emily on 8 July 2019

Pablo Lewin wanted a way to adjust the antenna for his Ham radio remotely, but was told his antenna controller was too old to upgrade for remote operation. That didn’t deter him though! He got creative and came up with a solution by connecting a stepper motor to his antenna controller and then using one of our Tic Stepper Motor Controllers. Now he can access the computer the Tic is connected to remotely and control the antenna’s position through the Tic’s software. Check out the video below to see his setup:


Here’s the video Pablo recommends at the beginning of his explanation to get up and running with your own Tic Stepper Motor Controller:

Independence Day Sale 2019

Posted by Emily on 2 July 2019


We are having an Independence Day sale from now through Monday, July 8! Check out the sale page for more information. Please note that we will be closed Thursday, July 4, so orders placed after 2 PM Pacific Time Wednesday, July 3 will be shipped on Friday, July 5.

New Products

6-Pin Female JST SH-Style Cable 30cm
ACHS-7125 Current Sensor Carrier -50A to +50A
ACHS-7124 Current Sensor Carrier -40A to +40A
Tic 36v4 USB Multi-Interface High-Power Stepper Motor Controller
Free Circuit Cellar magazine November 2019
Magnetic Encoder Pair Kit with Top-Entry Connector for Micro Metal Gearmotors, 12 CPR, 2.7-18V
Tic 36v4 USB Multi-Interface High-Power Stepper Motor Controller (Connectors Soldered)
Free Circuit Cellar magazine October 2019
RoboClaw 2x60A Motor Controller (V7)
6-Pin Female JST SH-Style Cable 12cm
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