# Pololu Blog (Page 8)

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.

# New-ish product roundup: 24 more QTR arrays, MP6500 carriers with soldered headers, and a pressure sensor

Posted by Ben on 20 September 2018

We’ve been hard at work over the past week putting up lots of new (but perhaps familiar-seeming) products. Here’s a quick recap:

## 24 new QTR reflectance sensor arrays

Our rapidly growing selection of new QTR sensors now includes high-density (HD) versions with 3, 6, and 9 channels, and medium-density (MD) versions with 2, 3, and 5 channels.

Each of these is available with two sensor options—traditional QTR and high-performance, low-current QTRX—and with analog or digital (RC) outputs, making 24 new products in all. Check out the QTR reflectance sensor category to see our full selection, which now stands at 68 varieties, and don’t forget to use our QTR introductory promotion to get 50% off any of these new sensors! (Limited to the first 100 customers who use coupon code QTRINTRO, limit 3 per item per customer.)

## MP6500 stepper motor driver carriers with soldered header pins

We have received a number of requests to make the MP6500 stepper motor driver carriers we released earlier this year available with the header pins already soldered, so here they are! These carriers are available in two versions, one with the current limit set by a potentiometer, and one that allows for dynamic current limit control through a pair of digital inputs, and both are now available with soldered header pins:

For a more detailed introduction to these drivers, see our original MP6500 carrier product announcement.

## LPS25HB pressure/altitude sensor carrier

This is a minor update to our existing LPS25H pressure sensor carrier, which is now on clearance. The new version uses the same PCB as the original, hence the “©2014” on the silkscreen. and replaces the LPS25H with the newer LPS25HB, a drop-in replacement with the same register map and performance. Most people shouldn’t notice any difference using the new version compared to the old one, though ST says in their LPS25H upgrade guide (200k pdf) that the LPS25HB has better moisture resistance and reliability. That said, please keep in mind that we have not characterized the moisture resistance of the rest of the carrier, and moisture is generally something we recommend you keep away from all of our electronics.

Visually, the LPS25HB is easy to distinguish from the LPS25H as the former has a shiny silver square patch on the package while the latter has a more noticeable hole:

We have already started making our AltIMU-10 v4 and AltIMU-10 v5 IMUs with the LPS25HB, and we did so without using new product numbers or updating the pictures or descriptions because this change should not affect those products in any meaningful way (we have a new product number for the updated basic carrier since the specific sensor on there is pretty much the whole point of the product).

On a related note, we still have a lot of the even older LPS331AP pressure sensors/digital barometers left, so we have put the LPS331AP carriers on even more clearancy clearance!

# New products: 5-channel QTR HD reflectance sensor arrays

Posted by Ben on 10 September 2018
Tags: new products

We now have five-sensor versions of our new high-density 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, so this post covers four new products:

(Medium-density versions with 3 sensors on an 8 mm pitch will be available soon.)

We expect these to be the smallest arrays that still offer independent control of the odd and even emitters, which gives you extra options for detecting light reflected at various angles. For more information on our new QTR sensor family, you can see some of our previous blog post about the versions we have already released:

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.)

# Labor Day weekend sale

Posted by Ben on 31 August 2018

We are having a Labor 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 today (Friday, August 31) will be shipped on Tuesday, September 4.

# New products: D36V6x step-down regulators

Posted by Jan on 31 August 2018

Wrapping up our new product releases for the month and for the summer is our new D36V6x family of step-down voltage regulators. These small regulator modules support a large input voltage range and are a great alternative to old three-terminal linear voltage regulators that waste a lot of power and get really hot. These new regulators can take an input voltage anywhere from a few tenths of a volt over the set output voltage up through an absolute max of 50 V, and they can deliver up to 600 mA. We have them available in seven fixed voltage options and two adjustable versions:

You might notice that the board for the adjustable version shows a 2010 copyright year (the fixed version is an even smaller board, and we did not fit the year on there). That’s because these new regulators are actually old designs updated with new regulator chips that use the same package and pinout. The older products were our D24V3x and D24V6x families of regulators, which were based on the Texas Instruments LMR14203 and LMR14206 ICs. For the new D36V6x family, we are moving up to the newer LMR16006 regulator. This chip has several exciting new features that we think will make it our favorite general-purpose regulator for many of our products: higher maximum voltage, better low-dropout performance, and better quiescent current.

### Higher maximum voltage

The LMR16006 has a 60 V maximum input voltage, up from the 42 V of the LMR1420x parts. Even 42 V covered most of our typical applications, but it’s not quite enough for 36V nominal applications, which are getting more common. Our more advanced, integrated products such as motor controllers are often limited by some complex part or circuit, such as a motor driver, and we would like the overall operating range of the product not to be reduced by the regulator. Many stepper motor drivers, such as TI’s DRV8825 or the Toshiba TB67S249FTG and TB67S279FTG that we released carriers for in June, support maximum input voltages of 45 or 50 volts. It’s nice not to be limited by your regulator when you are making systems with those kinds of parts.

For our new D36V6x modules, we are limited to the 50 V maximum of the capacitors from Vin to ground. Unfortunately, capacitor options get a lot more restricted (and expensive) once we go beyond 50 V, so we decided to stick with our old boards so that we could continue to offer these regulator modules at a low price while still providing some substantial improvements. We might still make a new board with higher-voltage capacitors for those who would like to make full use of the regulator’s 60 V maximum. (For anyone thinking of just removing the caps and putting on your own external ones, you might also want to change the diode, which is also a 60 V part.)

### Better low-dropout performance

Having a higher maximum input voltage is nice, but often we’re trying to squeeze the most we can out of a dying battery, so it’s nice to have a low dropout, which is the voltage the regulator needs between the input and output. The older LMR1420x parts had an annoying quality of the dropout voltage going up as the load current went down. The newer LMR16006 has a nice, low dropout as the current goes down, so if you don’t need much current, you can get 5 V out with just 5.2 or 5.3 volts in. Here is a comparison of the dropout performance of the old and new regulators:

### Lower quiescent current

The new regulators also have much lower quiescent current, which is the current the regulator uses when it’s just sitting there and your load isn’t drawing anything. On the old regulators, the quiescent current was under 2 mA, and we did not characterize it beyond that. For these new regulators, it’s typically under 200 microamps, ten to twenty times better than the old regulators. I realize it’s not that amazing for modern regulators, but it’s nice to know that your low-cost, general-purpose regulator module isn’t wasting a lot of power.

Even when we put a new chip onto an old circuit board as I have described, we still test and characterize with different parts to get a good overall result. In the case of these regulators, where the circuit is quite simple, this phase of development is much more time consuming than laying out a circuit board. We build and test dozens of prototypes with different inductances, and even though you can’t see it in the pictures, we build the different voltage versions of the regulators with different inductors to get the best performance we can (within a given inductor type and size).

So how about getting a few to have around for general-purpose use on your next project? You can get one for just $3 as part of our introductory promotion using coupon code D36V6XINTRO, limited to the first 100 customers and to three per item (so you could get up to 27 regulators at that price if you get three of each voltage version). It’s always difficult for us to predict which versions will be how popular, so initial stock is limited, but we make these here in Las Vegas, so even if the version you want goes out of stock, you can backorder it with the promotional price, and we should be able to ship within a day or two. # New products: 1- and 31-channel QTR HD reflectance sensor arrays Posted by Jan on 31 August 2018 This week, we released what we expect to be the extremes of our new line of QTR HD reflectance sensor arrays, with two sizes of a single-sensor board on the small end and a massive 31-sensor array for the maximum size. This picture shows the relative sizes of the boards, along with some of the intermediate sizes we have available: We made the two single-sensor sizes because we could make good arguments for each one. Part of the point of doing a single-sensor board is to make it really small, so you can fit it into tight spaces. But “really small” means different things depending on the dimensions you care about. So we have one version that is only 5 mm (0.2") wide, with components on both sides of the PCB, and one version that is 7.5 mm (0.3") wide, with components on just one side. The 7.5 mm wide version is a little thinner and flatter because it doesn’t have parts on one side, can be used with a 3×1, single row connector, and costs slightly less because of the single-sided assembly. As I mentioned in some of my earlier posts (here and here) about this new line of sensor arrays, we are using two sensor types: more economical units we are calling “QTR”, and higher-performance units with lenses that we are calling “QTRX”. The main appeal of the QTRX sensors is that they can give the same readings at much lower IR emitter currents, which can really make a big difference for big sensor arrays. But if you crank up the current in those QTRX sensors, you can also get more distance. We did not do that on the QTRX arrays because the sensor modules leak light out the sides and interfere with each other when they are closely spaced, but with these single-channel boards, we are also making available the QTRX sensors with the higher 30 mA maximum emitter current, which allows for a range of up to about 8 cm (about 3 inches). We are calling these sensors QTRXL. This video (taken with an old camera that does not have as much IR filtering as most newer cameras) shows the IR light leakage around the side of the QTRX sensor module: I should point out that all of these new QTR modules offer variable brightness control by varying the current through the emitter using the control pin. However, if you want to take advantage of the maximum brightness and range, and have several sensors close to each other, you will need some barriers between them to prevent them from blinding each other (or just turn on one emitter at a time). The 31-sensor arrays are huge! Well, at least compared to the tiny single-sensor boards. The routing on those boards is quite complex because adjacent IR emitters are not just wired in series (because we want to have separate even/odd emitter control, plus the alternate density population options I discussed in this post), so we ended up having to go to a 4-layer PCB to route it. This did let us make the vertical dimension a little lower, so the board is just 16.5 mm tall, compared to the 20 mm board height for the versions with 15 and fewer sensors. The 31-channel board is also 0.062" (1.6 mm) thick, compared to the thinner 0.040" (1 mm) boards we use for the lower channel counts. You can compare all the dimensions of the various boards in the detailed dimension diagram (1MB pdf). The sixteen new boards we released this week brings the total available in this new QTR HD product line to 40. You can see the options neatly summarized in the tables below to pick the best array for your application. QTR sensors 2.9 V to 5.5 V; 30 mA max LED current(1); 5 mm optimal range Board width Configuration Max board current(2) Max range Output type Name 1-piece price 5.0 mm 1 sensor (HD) 32 mA 30 mm analog QTR-HD-01A$1.79
RC (digital) QTR-HD-01RC
7.5 mm 1 sensor (MD)
32 mA 30 mm analog QTR-MD-01A $1.61 RC (digital) QTR-MD-01RC 10.2 mm 4 mm × 2 32 mA 30 mm analog QTR-HD-02A$2.12
RC (digital) QTR-HD-02RC
17.0 mm 4 mm × 4
62 mA 40 mm analog QTR-HD-04A $3.26 RC (digital) QTR-HD-04RC 29.0 mm 8 mm × 4 62 mA 40 mm analog QTR-MD-04A$3.44
RC (digital) QTR-MD-04RC
4 mm × 7
125 mA 40 mm analog QTR-HD-07A $5.40 RC (digital) QTR-HD-07RC 61.0 mm 8 mm × 8 125 mA 40 mm analog QTR-MD-08A$6.39
RC (digital) QTR-MD-08RC
4 mm × 15
250 mA 50 mm analog QTR-HD-15A $10.82 RC (digital) QTR-HD-15RC 125.0 mm 4 mm × 31 495 mA 50 mm analog QTR-HD-31A$21.66
RC (digital) QTR-HD-31RC
QTRX sensors
2.9 V to 5.5 V; 3.5 mA max LED current(1); 10 mm optimal range
Board
width
Configuration Max board
current(2)
Max range Output
type
Name 1-piece
price
5.0 mm 1 sensor (HD)
5 mA 30 mm analog QTRX-HD-01A $2.17 RC (digital) QTRX-HD-01RC 7.5 mm 1 sensor (MD) 5 mA 30 mm analog QTRX-MD-01A$1.99
RC (digital) QTRX-MD-01RC
10.2 mm 4 mm × 2
5 mA 30 mm analog QTRX-HD-02A $2.88 RC (digital) QTRX-HD-02RC 17.0 mm 4 mm × 4 9 mA 40 mm analog QTRX-HD-04A$4.78
RC (digital) QTRX-HD-04RC
29.0 mm 8 mm × 4
9 mA 40 mm analog QTRX-MD-04A $4.96 RC (digital) QTRX-MD-04RC 4 mm × 7 17 mA 40 mm analog QTRX-HD-07A$8.06
RC (digital) QTRX-HD-07RC
61.0 mm 8 mm × 8
17 mA 40 mm analog QTRX-MD-08A $9.43 RC (digital) QTRX-MD-08RC 4 mm × 15 34 mA 50 mm analog QTRX-HD-15A$16.52
RC (digital) QTRX-HD-15RC
125.0 mm 4 mm × 31
68 mA 50 mm analog QTRX-HD-31A $33.44 RC (digital) QTRX-HD-31RC QTRXL sensors 2.9 V to 5.5 V; 30 mA max LED current(1); 20 mm optimal range Board width Configuration Max board current(2) Max range Output type Name 1-piece price 5.0 mm 1 sensor (HD) 32 mA 80 mm analog QTRXL-HD-01A$2.17
RC (digital) QTRXL-HD-01RC
7.5 mm 1 sensor (MD)

# New products: U3V70x high-current boost voltage regulators

Posted by Jan on 16 August 2018
Tags: new products

Today we are finally releasing our new U3V70x family of boost regulators, which are now our highest-current boost regulators. (I said “finally” because we have had the boards designed for over six months, but we just finally received the main ICs for our production builds even though I ordered them last year.) Besides supporting the most current of any of our boost regulators, we also have an adjustable version with a multi-turn trimmer potentiometer, which makes setting the output voltage to a particular value much easier than when the whole output voltage range is represented by the 250 degrees or so of a single-turn pot. The regulators operate with input voltages down to 2.9 V, and the adjustable output version can be set to an output in the range of 4.5 V to 20 V. Talking about the current on boost regulators is tricky since it’s so dependent on input and output voltages, so it’s best to just show you a few performance graphs:

For those who don’t need adjustability (that multi-turn pot is expensive!), we offer fixed-voltage versions in six standard voltages:

We can also make customized fixed versions for you with other voltages between 4.5 V and 20 V.

It’s exciting that these new regulators are smaller than what used to be our highest-power boost regulator (the U3V50x family) despite handling more current. One way we kept the size smaller is by using only ceramic capacitors. One consequence of that is that the new regulator outputs are slightly noisier, so if that is important for your application, you might want to add some external capacitors to further smooth out the voltage. The older design also supports a higher maximum output voltage, so if you need more than 20 V, our U3V50F24 fixed 24 V and U3V50AHV adjustable 9 V to 30 V units are still our highest-power options.

As with all our new products this year, we are offering a special introductory promotion. You can get up to three of each version for just \$9 (which is an especially good deal for the adjustable regulator!), limited to the first 100 customers using coupon code U3V70XINTRO.

# New products: QTR HD sensor arrays by student engineering interns

Posted by Matthew H. on 10 August 2018
Tags: new products

Hi everyone! My name is Matthew, and I am one of nine student engineering interns working at Pololu this summer. As I was preparing to head back to MIT for my sophomore year of studying Mechanical Engineering, I was graciously inflicted with the responsibility of announcing our second wave of high-density QTR reflectance sensor arrays. These two- and four-sensor boards, along with all of the other soon-to-be-released QTR sensor arrays, were designed by us student interns. For many of us, these boards were the first we ever routed, so it’s especially exciting to see them be real products going out into the world. While I did not personally lay out any of the boards being released today, we all thoroughly cross-checked each other’s work (the first board I directly routed should be released next week).

Because of their small size, these boards have one LED brightness control pin. All boards with more than four sensors will have separate LED brightness control for odd-numbered and even-numbered LEDs.

As Jan mentioned in the first blog post introducing this line of sensors, each board is available in analog and RC configurations and with two different sensor types. This post therefore covers the release of eight new products:

We have also released an update to our QTR Arduino library for use with these new QTR sensor arrays.

As we have been doing with all our new products this year, we are offering an extra special introductory discount on these boards! The first 100 customers using coupon code QTRINTRO will get half off on up to three of each sensor.

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