Posts by Claire

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“Knock knock unlock” puzzle box

Posted by Claire on 1 December 2016

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.

New D24V150Fx 15A step-down voltage regulator family — our highest-power regulators yet!

Posted by Claire on 1 November 2016
Tags: new products

I am excited to announce that we just released our highest power regulators ever. The new D24V150Fx family of step-down regulators includes units with 3.3 V, 5 V, 6 V, 7.5 V, 9 V, and 12 V outputs and can output currents of around 15 A! With all of the output voltages available, the D24V150Fx family of regulators is great for a variety power-hungry projects like running servos or our metal gearmotors and supplying large LED displays.

Pololu Step-Down Voltage Regulator D24V150Fx in a breadboard, assembled with terminal blocks and male headers.

Pololu Step-Down Voltage Regulator D24V150Fx, bottom view with dimensions.

The maximum continuous output currents for all the members of the D24V150Fx family are shown in the graph below. You can see that the available output current is generally a little higher for the lower-voltage versions than it is for the higher-voltage versions, and it decreases as the input voltage increases.

These regulators accept input voltages up to 40 V and have typical efficiencies between 80% and 95%. Integrated reverse-voltage protection, over-current protection, over-temperature shutoff, undervoltage lockout, and soft-start features make these regulators robust, and a power good output can be used to monitor the output voltage.

See the product pages for any of the D24V150Fx regulators for more information on these new regulators, or visit our voltage regulator category to see all of our regulator options.

Remote control food

Posted by Claire on 6 October 2016

With Halloween on its way, and trick-or-treating eminent, you might be asking yourself if there are any alternative uses for the mountain of candy bars your kids will soon be bringing home. Well, customer Mike Kohn, whose projects we previously blogged about, has a solution for giving new life to not just candy, but all sorts of unwanted food items: remote controlled food!

For this project, Mike ditched plastic and aluminum and tried out a sampling of more savory chassis materials like candy bars, a carrot, a bell pepper, a grapefruit, and a chicken sausage. The candy bars, carrot, and sausage were used for four-wheeled differential drive cars and the pepper and grapefruit were used for boats. All the vehicles were actuated by a pair of micro metal gearmotors and the cars also used our 32mm wheels. Below is a picture of one car made with a 3 Musketeers bar.

Mike also wrote his own firmware for decoding the IR signals from a Syma S107 controller. You can find out which foods made the best chassis and plenty more information about the vehicles, including a parts list, schematic, and several other videos, on Mike’s website.

Video: Smart lane changing Zumo robot

Posted by Claire on 7 September 2016

Forum member WaterBoy23 recently shared his robot which expanded upon the line following capabilities of our Zumo Robot for Arduino by adding in lane changing capabilities. The robot changes lanes when it detects a vehicle ahead of it, and is programmed to either pass the vehicle or return quickly to its original lane if it detects oncoming traffic. His robot uses two Arduino Uno boards, one for following the line and the other for reading ultrasonic position sensors. More information about the robot can be found in WaterBoy23’s post on our forum.

New product: DRV8880 Stepper Motor Driver Carrier

Posted by Claire on 1 April 2016
Tags: new products

I’d like to introduce our latest addition to the Pololu stepper motor driver carrier family, the DRV8880 Stepper Motor Driver Carrier. This carrier for the Texas Instruments DRV8880 driver has the same form factor and basic layout as our A4988 carrier, which makes it a drop-in replacement in many systems. It also has a lot of the same features, like potentiometer adjustable current control and microstepping down to 1/16-step. In addition, the DRV8880 has many new features like inputs for dynamically scaling the current limit to 25%, 50%, 75%, or 100% of the limit set by the potentiometer, nine decay mode combinations, and autotune (insert Daft Punk joke here), which automatically selects the decay mode each PWM cycle for optimal current regulation performance.

The DRV8880 carrier has a maximum current of 1.6 A, and in our tests it could handle about 1 A per phase continuously. It has a 6.5 V to 45 V input voltage range, which is the widest of any of our stepper motor drivers, and it supports both 3.3 V and 5 V logic. For more information about our DRV8880 stepper motor driver carrier, please see its product page.

Pololu at the Las Vegas Mini Maker Faire 2016

Posted by Claire on 11 March 2016


The local Las Vegas hackerspace, SYN Shop, hosted the third Las Vegas Mini Maker Faire at the Henderson Convention Center recently. The event showcased a wide variety of projects and skills: drones, sand casting metal using aluminum cans, woodworking, taiko drumming, and of course robots. At our booth, Pololu showed off some older demos, like our Simple Motor Controller demo and our jrk treasure chest; some newer demos, like the motion tracking skull from Halloween; and some fun robots, like the Zumo 32U4 and Paul’s Raspberry Pi Robot. Above is a short video with highlights from the event.

Room mapping robot based on the Rover 5 chassis

Posted by Claire on 19 February 2016

This robot, created by theophil on Let’s Make Robots, uses a Rover 5 chassis with encoders, a MinIMU, sonar sensors, and a few expansion plates to do room mapping. Theophil modified the chassis to use Dagu Wild Thumper wheels, and made a custom 3D-printed adapter for connecting the wheels in a compact way. The program for the robot, which is available on GitHub, collects data from the sonar sensors about how far away objects are and creates a grayscale map where the darkness of a pixel corresponds to the robot’s confidence that an obstacle exists in that spot.

Example map made by theophil’s mapping rover.

The program also includes a movement algorithm meant to drive the robot along paths that take it close to many obstacles to increase the accuracy of the sonar sensors. More about theophil’s room mapping robot can be found in his Let’s Make Robots post.

S3 Pilot board robot

Posted by Claire on 28 August 2015

Forum member spiked3, whom we previously posted about, has shared another robot with a custom laser cut chassis. The new robot uses his own custom Arduino shield, the S3-Pilot, which has sockets for an IMU and two of our MC33926 Motor Driver Carriers.

Custom Arduino shield created by forum member spiked3.

The MC33926 drivers control two 37D motors with encoders, and the encoder signals are processed by the Arduino. The robot also includes a lidar, PIXY Cam, and Raspberry Pi. The on-board IMU and encoders allow the robot to keep track of where it is and what direction it is facing, so spiked3 was able to implement a high-level interface for the robot that accepts movement commands like “go forward three meters” or “turn a certain number of degrees to the right”.

You can find out more about this robot and see some videos of it being tested on spiked3’s blog.

Claire's line following robot: Oddish

Posted by Claire on 7 May 2015
Claire's line following robot: Oddish

A few weeks ago the local robotics club, LVBots, hosted a line following competition here at Pololu, and like many of the engineers here, I built a robot, which I named Oddish, for the competition. I really only started seriously working on my robot about a week before the competition, so when I made the final decisions about what components to use I aimed for simplicity. In the last year we have come out with several A-Star microcontroller boards that include switching regulators, so I thought it would be fun and simple to make a line follower using an A-Star as the brain and its built-in 5 V regulator to power all the other components. I chose the A-Star 32U4 Mini LV for its operating voltage range and size. Continued…

Video: Setting the Current Limit on Pololu Stepper Motor Driver Carriers

Posted by Claire on 14 April 2015

One of my many roles here at Pololu is overseeing technical support, and I have seen countless cases of customers who have problems with their stepper motor systems because they have not properly set the current limit on their stepper motor driver. To address the issue, we have made a new video that demonstrates how to set the current limit on our stepper motor driver carriers. The video also provides helpful tips and points out a few common pitfalls.

A DRV8825 carrier is used for the demonstration, but the video also applies to our A4988, DRV8824, and DRV8834 stepper motor driver carriers. In the demo, signals for the driver are provided by an Arduino-compatible A-Star 32U4 Prime SV. Here is a simplified version of the Arduino code from the video that can be used to step a motor in both directions:

/* Simple step test for Pololu stepper motor driver carriers 
This code can be used with the A4988, DRV8825, DRV8824, and 
DRV8834 Pololu stepper motor driver carriers.  It sends a pulse 
every 500 ms to the STEP pin of a stepper motor driver that is 
connected to pin 2 and changes the direction of the stepper motor
every 50 steps by toggling pin 3. */

#define STEP_PIN 2
#define DIR_PIN 3

bool dirHigh;

void setup()
{
  dirHigh = true;
  digitalWrite(DIR_PIN, HIGH);
  digitalWrite(STEP_PIN, LOW);
  pinMode(DIR_PIN, OUTPUT);
  pinMode(STEP_PIN, OUTPUT);
}

void loop()
{
  // Toggle the DIR pin to change direction.
  if(dirHigh)
  {
    dirHigh = false;
    digitalWrite(DIR_PIN, LOW);
  }
  else
  {
    dirHigh = true;
    digitalWrite(DIR_PIN, HIGH);
  }

  // Step the motor 50 times before changing direction again.
  for(int i = 0; i < 50; i++)
  {
    // Trigger the motor to take one step.
    digitalWrite(STEP_PIN, HIGH);
    delay(250);
    digitalWrite(STEP_PIN, LOW);
    delay(250);
  }
}

New Products

Pololu 5V, 15A Step-Down Voltage Regulator D24V150F5
Pololu 7.5V, 15A Step-Down Voltage Regulator D24V150F7
Free Circuit Cellar magazine November 2016
Addressable RGB 60-LED Strip, 5V, 2m (SK6812)
Addressable RGB 150-LED Strip, 5V, 5m (SK6812)
Pololu 6V, 15A Step-Down Voltage Regulator D24V150F6
Raspberry Pi Model A+ 512MB
Addressable RGB 60-LED Strip, 5V, 1m (SK6812)
Addressable RGB 120-LED Strip, 5V, 2m (SK6812)
UM7 Orientation Sensor
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