Pololu Blog (Page 3)

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…

Distributor Active Robots attends micromouse challenge at Swansea University

Posted by Emily on 28 May 2019


One of our UK distributors, Active Robots, recently had the opportunity to attend a micromouse competition at Swansea University in Wales. Students at the competition used many Pololu parts purchased through Active Robots including our laser-cut RRC01A chassis, 50:1 micro metal gearmotor LP, 42×19mm Wheel Pair, and 3/8″ Plastic Ball Caster.

Traditional micromouse competitions usually involve small autonomous robots competing to see which one can solve a maze the fastest. Swansea University’s competition didn’t include maze solving, but instead involved three tasks that the robots had to complete: line following, obstacle avoidance, and combat. You can read more about what the micromouse competition entailed and Active Robots’ visit on their blog.

Memorial Day Sale

Posted by Emily on 23 May 2019


We are having a Memorial 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 Friday, May 24 will be shipped on Tuesday, May 28th.

New 5:1 Glideforce light-duty linear actuators

Posted by Ben on 21 May 2019
Tags: new products

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

New products: ACS724 current sensor carriers

Posted by Ben on 17 May 2019
Tags: new products

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:

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


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
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 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!

Video: How to Say Pololu!

Posted by Emily on 8 May 2019
Tags: pololu videos

The name Pololu is simple, but over the years, we’ve noticed some customers mispronouncing our name or hesitating to say it. And if you can’t say our name, how will you tell your friends about us? So if you are unsure about how to say Pololu, I hope this little video will help you out:

New product: Silicone Tires for Pololu wheels

Posted by Jon on 1 May 2019
Tags: new products

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.

Laser-cut teapot coasters

Posted by Claire on 24 April 2019

This past weekend my mom hosted a tea-themed baby shower for me, and after looking around and not finding any party favors I liked, I decided to make my own custom laser-cut teapot-shaped coasters for it. To get started, I searched some free vector file sites for a vector file of a teapot that I liked and could easily prepare for laser-cutting with CorelDRAW. I chose this one designed by Freepik. Once loaded into the software, I resized the teapot and added text. I personally really like cork as a coaster material since it keeps the cup from slipping and absorbs moisture well, so I also picked up some 1/8″ cork place mats from IKEA.

Evidently, cork is not a material we are asked to laser-engrave very often, so I had to do some experimenting with the engraving settings before cutting out prototypes.

I generally liked the look of the first draft, but realized that at 4 inches total width it was too small to be practical (and readable). In addition, the handle of the teapot was fairly fragile since the cork was only an eighth of an inch thick. Below you can see the first draft of the cork teapot in the upper left. It is missing the small circular embellishment at the base of the handle.

Comparison of different test coaster sizes.

For the second draft, I increased the size to about 5.5 inches, edited my file to thicken the areas of the teapot where the handle connects to the base, and started playing with different acrylic backings to make the coasters more durable and colorful. I tried a version with an outline around the cork teapot and one that fit directly beneath the cork.

In the end, I went with the sleeker acrylic with no outline, though most of the others I consulted here preferred the mirrored outline shown on the left above (despite my insistence that it looked like a magic lamp). I cut out a variety of colors and glued them to the back of the cork with rubber cement.

All in all I think they came out well (though I could have made the attachment for the small circle at the bottom of the handle even thicker), and they were definitely a big hit at the party!

If you want to try your own laser cutting project, submit a quote request here!

New product: DB15 Screw Terminal Adapter for MCP23X/26X Advanced Motor Controllers

Posted by Jon on 19 April 2019
Tags: new products

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).

New products: D36V28Fx Step-Down Voltage Regulators

Posted by Ben on 12 April 2019
Tags: new products

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:

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!

Pololu National Robotics Week Sale

Posted by Emily on 5 April 2019


Next week is National Robotics Week: a week centered on increasing awareness of the robotics industry and the impact that robotics will have on the future. To celebrate, we’re having a sale! All Pololu robot kits and their accessories are 25% off; this includes our 3pi, Zumo, Balboa, and Romi robots. Additionally, all active Pololu-brand items are 20% off, so you can stock up on motor controllers, regulators, sensors and much more! Whether you are a seasoned robot builder or just getting started in robotics, you are sure to find something in this sale for you. Check out the sale page for more information.

New Products

6-Pin Female JST SH-Style Cable 12cm
6-Pin Female JST SH-Style Cable 30cm
6-Pin Female JST SH-Style Cable 75cm
RoboClaw 2x60A Motor Controller (V7)
Magnetic Encoder Pair Kit with Top-Entry Connector for Micro Metal Gearmotors, 12 CPR, 2.7-18V
Free Circuit Cellar magazine November 2019
Magnetic Encoder Pair Kit with Side-Entry Connector for Micro Metal Gearmotors, 12 CPR, 2.7-18V
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