Drew Wilkerson added a Robotis BT-410 Bluetooth-to-serial board to his Balboa Robot, which allows him to control that Balboa from a cell phone. You can watch the video above to see the Balboa being driven around as it balances. More information about this project, including the code running on Drew’s Balboa, can be found in his post on our forum.

Related products

Balboa 32U4 Balancing Robot Kit (No Motors or Wheels)

We do a lot of laser cutting here at Pololu as part of our custom laser-cutting service, so we know first hand how tedious it can be to remove the paper masking from laser cut parts like acrylic. Check out the video below for a simple trick you can use to speed up the process.

Related products

Custom Laser Cutting Service

QTR-MD-16A Reflectance Sensor Array.

We now have 16-sensor, medium-density (8mm-pitch) versions of our new QTR reflectance sensor arrays. Like the versions already released, these new modules are available in analog and RC configurations and with two different sensor types, resulting in four new products in all:

• QTR-MD-16RC Reflectance Sensor Array
• QTR-MD-16A Reflectance Sensor Array
• QTRX-MD-16RC Reflectance Sensor Array
• QTRX-MD-16A Reflectance Sensor Array

Unlike the medium-density (MD) arrays we have released previously, which just use the high-density PCBs in partially populated configurations, these new 16-channel modules use PCBs specifically designed for an 8 mm pitch. As a result, these are the first MD versions that allow separate control of the odd and even emitters, which gives you extra options for detecting light reflected at various angles. They have the same board dimensions (125 × 16.5 mm) and mounting hole locations as the high-density (4mm-pitch) 31-channel arrays, but the pinout is different.

QTR-MD-16A Reflectance Sensor Array.

QTR-HD-31A Reflectance Sensor Array.

For more information on our new QTR sensor family, you can see some of our previous blog posts about the versions we have already released:

• New products: 1- and 31-channel QTR HD reflectance sensor arrays
• New products: more new QTR HD sensor arrays by student engineering interns
• New products: QTR HD sensor arrays by student engineering interns
• New product: high-density QTR reflectance sensor arrays

Don’t forget to get in on our QTR introductory promotion! Be one of the first 100 customers to use coupon code QTRINTRO and get any of these new sensors at half price! (Limit 3 per item per customer.)

Related products

	QTRX-MD-16RC Reflectance Sensor Array: 16-Channel, 8mm Pitch, RC Output, Low Current
	QTRX-MD-16A Reflectance Sensor Array: 16-Channel, 8mm Pitch, Analog Output, Low Current
	QTR-MD-16RC Reflectance Sensor Array: 16-Channel, 8mm Pitch, RC Output
	QTR-MD-16A Reflectance Sensor Array: 16-Channel, 8mm Pitch, Analog Output

We now have a 5-Channel Reflectance Sensor Array designed specifically for use with the Balboa 32U4 Balancing Robot. The array mounts to the Balboa 32U4 control board and provides an easy way to add line sensing to the Balboa (but following a line while balancing is actually kinda hard—and that part is up to you, should you accept the challenge).

The array features five IR emitter/phototransistor pairs with dimmable brightness control similar to our line of QTR reflectance sensors.

As with all of our new products this year, we are offering an introductory special. The sensor by itself is already inexpensive, so just discounting that did not seem exciting enough. To make it more celebratory, we decided to offer a special promotion for the whole Balboa package: you can get a Balboa 32U4 robot kit with motors, wheels, and the new 5-Channel Reflectance Sensor Array for just $79! To get the discounted price, add this special promotion product bundle and coupon code BALBOAREFLECT to your cart. Offer is limited to the first 100 customers, limit one per customer. If you already have a Balboa, or if you want different motors or wheels than what’s included in the bundle, you can use coupon code BALBOAREFLECT2 to save 35% (limit 2 per item).

Related products

	5-Channel Reflectance Sensor Array for Balboa 32U4 Balancing Robot
	Balboa 32U4 Balancing Robot Kit (No Motors or Wheels)
	Special Promotion: Balboa 32U4 Balancing Robot Kit with Gearmotors, Wheels, and Reflectance Sensor Array

We will be closing early on Monday, December 24, so our same-day shipping cutoff will be noon Pacific time instead of the usual 2 PM. We will be closed for Christmas on Tuesday, December 25. Orders placed after noon Pacific time on Monday, December 24 will be shipped on Wednesday, December 26.

And last call for our Christmas sale — only about 12 hours to go! Merry Christmas!

We are excited to announce the newest additions to our selection of servos:

• FEETECH FS90-FB Micro Servo with Position Feedback
• FEETECH FS5103B-FB Standard Servo with Position Feedback

These specially modified versions of the standard FEETECH FS90 and FS5103B servos provide direct access to the feedback potentiometer through an extra fourth wire. Additionally, the FS90-FB has an extra long cable relative to the standard FS90 micro servo. The inclusion of a feedback wire allows you to monitor the servo’s position, which is especially useful for more complex robotic applications. For example, it can be used for determining if the servo is stalled or when it has reached it’s target position. It also allows you to implement your own higher-level closed-loop position control or create servo movements by hand that you can record and play back later. This feedback voltage varies linearly over the servo’s range of motion.

These servos are similar to those used in the Robot Arm Kit for Romi and Micro Gripper Kit and can be used as replacements for those servos.

These are just the start of our eventual selection of FEETECH servos with position feedback, so keep an eye on our blog and New Products category for more to come!

Related products

	FEETECH FS90-FB Micro Servo with Position Feedback
	FEETECH Standard Servo FS5103B-FB with Position Feedback
	FEETECH FS90 Micro Servo
	FEETECH Standard Servo FS5103B

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 15% off twelve broad categories of our products. The sale runs through Friday, December 21, 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!

We have yet another new stepper motor driver carrier in our popular 16-pin, 0.6″ × 0.8″ form factor, this time for STMicro’s STSPIN820, which offers 1/256 step microstepping! ST actually has their own similar evaluation board, the EVALSP820-XS, but the STSPIN820 chip has a non-inverted Enable input, which is inverted compared to most other stepper motor driver ICs out there, and they expose the pin that way on their version of the board. We have thoughtfully added a transistor-based inverter so that our board is more likely to work as a drop-in replacement (or upgrade!) for the stepper driver boards you already have. In our tests, the Pololu carrier supported a substantially higher maximum current than the ST eval board (around 900 mA compared to 720 mA, probably due to our board having four layers vs. two layers for the ST eval board), and as of this writing (27 November 2018), our board is also priced lower.

You can see the full schematic for all the details (this schematic is also available as a downloadable pdf (109k pdf)):

Schematic diagram of the STSPIN820 Stepper Motor Driver Carrier.

With our release earlier in November of compact carriers for Toshiba’s TB67S249FTG and TB67S279FTG stepper motor drivers, we now offer ten different stepper motor driver modules in this compact size:

	A4988 (original)	A4988, Black Ed.	DRV8825	DRV8834	DRV8880	MP6500, Pot. CC	MP6500, Digital CC	TB67S279­FTG	TB67S249­FTG	STSPIN­820
Driver chip:	A4988		DRV8825	DRV8834	DRV8880	MP6500		TB67S279­FTG	TB67S249­FTG	STSPIN­820
Min operating voltage:	8 V		8.2 V	2.5 V	6.5 V	4.5 V		10 V	10 V	7 V
Max operating voltage:	35 V		45 V	10.8 V	45 V	35 V		47 V	47 V	45 V
Max continuous current per phase:(1)	1 A	1.2 A	1.5 A	1.5 A	1 A	1.5 A		1.1 A	1.6 A	0.9 A
Peak current per phase:(2)	2 A		2.2 A	2 A	1.6 A	2.5 A	2 A	2 A	4.5 A	1.5 A
Microstepping down to:	1/16		1/32	1/32	1/16	1/8		1/32	1/32	1/256
Board layer count:	2	4	4	4	4	4		4	4	4
Special features:			high current	low-voltage operation, high current	AutoTune, digital current reduction	high current	digital current control, high current	Auto Gain Control, ADMD, high max voltage	Auto Gain Control, ADMD, high max voltage, high current	128 and 256 microsteps
1-piece price:	$4.49	$4.95	$15.95	$7.95	$8.95	$6.95	$6.95	$10.75	$12.95	$14.95
1 On Pololu carrier board, at room temperature, and without additional cooling. 2 Maximum theoretical current based on components on the board (additional cooling required).

As with all of our new products this year, we are offering an introductory special. The first 100 customers that use coupon code STSPIN820INTRO can get up to five units at just $5 each.

Related products

STSPIN820 Stepper Motor Driver Carrier

Things are slowing down in our warehouse as our biggest sale of the year winds down, and to all those who have ordered, thank you! There’s still time for you to get in on today’s deals if you haven’t already, but don’t wait too much longer: the deals end at midnight Pacific time.

Our friends at Adafruit are also having a Cyber Monday sale, with 20% off on their CircuitPython product line and 15% off sitewide. See their blog post for more details!