Our vast assortment of metal gearmotors has gotten even bigger! With over 100 micro metal gearmotor options and nearly 100 25D mm metal gearmotor versions to choose from, the next step seemed clear: expand our offering of 20D mm metal gearmotors, which fit nicely between the smaller micro metal gearmotors and larger 25D mm metal gearmotors. We have replaced our initial four 20D mm options with twelve entirely new gear ratios that feature more efficient gearboxes and much longer output shafts.

Original 20D mm metal gearmotor with shorter output shaft.

New 20D mm metal gearmotor with longer output shaft.

The motor portion is unchanged, and we now also offer versions with an extended motor shaft that rotates at the same speed as the input to the gearbox and can be used to add an encoder, such as our new magnetic encoder for 20D mm metal gearmotors, for closed-loop speed or position control.

20D mm metal gearmotor with precious metal brushes and extended motor shaft.

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

The table below shows our current offering of 20D mm metal gearmotors:

Rated Voltage	Stall Current @ Rated Voltage	No-Load Speed @ Rated Voltage	Approximate Stall Torque @ Rated Voltage	Single-Shaft (Gearbox Only)	Dual-Shaft (Gearbox & Motor)
6 V	3.2 A	560 RPM	30 oz-in	25:1 6V	25:1 6V dual-shaft
		450 RPM	35 oz-in	31:1 6V	31:1 6V dual-shaft
		225 RPM	60 oz-in	63:1 6V	63:1 6V dual-shaft
		180 RPM	75 oz-in	78:1 6V	78:1 6V dual-shaft
		140 RPM	90 oz-in	100:1 6V	100:1 6V dual-shaft
		110 RPM	100 oz-in	125:1 6V	125:1 6V dual-shaft
		90 RPM	115 oz-in	156:1 6V	156:1 6V dual-shaft
		70 RPM	125 oz-in	195:1 6V	195:1 6V dual-shaft
		55 RPM	140 oz-in	250:1 6V	250:1 6V dual-shaft
		45 RPM	150 oz-in	313:1 6V	313:1 6V dual-shaft
		35 RPM	160 oz-in	391:1 6V	391:1 6V dual-shaft
		29 RPM	170 oz-in	488:1 6V	488:1 6V dual-shaft

We also have 12V versions on the way, so stay tuned for more information!

Related products

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

Here is a brief video a customer just sent us showing how he used our custom laser cutting service to create the frame on his custom 6-string banjo.

Are you attending CES or in Las Vegas this Friday evening? You can join Pololu and LVBots on January 6 any time from 5 p.m. to 8 p.m. for CES Open House 2017! Like last year, LVBots members will be showcasing their robotics and electronics creations, Pololu will be giving tours of our manufacturing and other operations, and you can present your company or your projects. We will provide pizza. Registration and other details are on the LVBots Meetup page.

We will be closed for Christmas on Monday, December 26 and for New Year’s Day on Monday, January 2, so orders placed after 2 PM Pacific Time on the 23rd or 30th will be shipped on the following Tuesday. Additionally, FedEx Ground does not ship on the 23rd (today).

Merry Christmas and happy New Year!

With the holiday season upon us, many are on the hunt for interesting projects that we can give as gifts. This year, why not make your project about unveiling your gift? You would still have to get an actual gift to put inside the box, but you’d win major style points. Forum member Bob Day’s knock knock unlock puzzle box has no visible way of opening it, but given the right combination of knocks will unlatch itself with the help of a servo and several other electronic components inside. The puzzle box is controlled by an A-Star Micro, which is powered by our S7V8F5 voltage regulator and a mini LV pushbutton power switch. The power switch is turned on by a mercury tilt switch and turned off by the A-Star if no knocks are received for about 30 seconds. This power switch circuit allows power to be completely turned off, which should extend the battery life tremendously over just leaving the A-Star on. (For advanced microcontroller programmers, another option would be to put the A-Star into a low-power mode.) A list of the parts and connections used and some example code for the box are given on Bob’s blog.

“Knock Knock Unlock” Puzzle Box outside view.

If you found this project interesting, you might also like a similar GPS puzzle box, also created by Bob, that we featured on our blog last year. That box unlocked when brought to a specific location and included a simpler toggle switch for power and an LCD screen.

Related products

	Mini Pushbutton Power Switch with Reverse Voltage Protection, LV
	Pololu 5V Step-Up/Step-Down Voltage Regulator S7V8F5
	A-Star 32U4 Micro
	3-AA Battery Holder

Here at Pololu, we think our Zumo 32U4 Robot is great! It’s one of our flagship products – a compact little robot packed full of features and tailored for mini-sumo. Whether you are a high school or college student learning to program through the Arduino IDE, or you are a C++ programming god and want to dabble in hardware for mortals, we think it’s a fantastic robot that you’d really enjoy. But, hey, you don’t have to take our word for it! Josh over at Breakout Bros has started a review series on robot kits, and recently posted his review of the Zumo 32U4. Check it out!

Have an opinion about that review? Maybe you have existing reviews of our products that you haven’t already shared with us? Feel free to post a comment about any of that below, or share your opinion on our forum. If you prefer, you can also contact us directly.

Forum user ZipZaps shared a fantastically charming project that uses a 24-channel Maestro servo controller to automate a Smith Corona typewriter using the speech recognition built into Windows. The Maestro controls a mechanism consisting of multiple rows of servos on some small linear rails to strike the keys in a manner resembling the way a person would normally interact with the typewriter. An Arduino paired with a Big Easy driver controls the stepper motor used to slide the carriage return system.

You can find more pictures and information about this project in ZipZaps forum post.

Related products

Mini Maestro 24-Channel USB Servo Controller (Assembled)

We have had a lot of fun with this year’s Black Friday/Cyber Monday sale so far, and I hope many of you have, too. The sale isn’t over yet, but it will be soon, so make sure you get any last-minute orders placed in the next eight hours!

Also, a big thank-you to the shipping department for getting all the orders out (especially to those who came in on the weekend to make sure everything went smoothly)!

Our Black Friday / Cyber Monday sale is going strong, and we have been working hard to make and ship the products that people are getting great deals on. If you have already placed an order, thank you! If you are still trying to decide if you want to take advantage of our amazing deals, don’t wait too long—the sale ends Monday night.

We’re less than two days away from our annual Black Friday/Cyber Monday sale, our biggest sale of the year! This year, in addition to our usual doorbuster deals (limited total quantity promotions at extreme discounts) and large discounts, we are offering up to $7 off of shipping for those who claim their coupon before the sale begins. For many of our smaller items shipping within the US, that discount will be enough to make shipping free, and it should also make a meaningful reduction in shipping costs for our international customers who want to participate in this American tradition. To take advantage of this offer, just log in to your account and follow this link, which will generate a coupon code just for you. You must get your coupon before the sale begins, and you can then use it during our sale, which will run from Wednesday, November 23 through Monday, November 28. Keep an eye on our Black Friday/Cyber Monday sale page for all the latest about the sale!