Pololu Blog (Page 2)

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.

Brandon's line following robot: The Chariot

Posted by Brandon on 6 May 2015
Brandon's line following robot: The Chariot

For the recent LVBots line following competition, my first instinct was to try to come up with some unique alternative design for a robot that would be competitive with the traditional differential drive robots. However, I knew the winning robot from the last LVBots line following competition (Mostly Red Racer) would be returning, and it had an impressive time to beat. I also remembered spending so much time designing and assembling the hardware for my last line following robot, that I ended up not having enough time to tune the PID coefficients and get the performance I was hoping for. After brainstorming a few ideas, I ended up deciding to keep it simple and make sure I had enough time to get a robot I was happy with, which I ultimately named “The Chariot” because of its shape. The Chariot ended up winning second place in the competition, which I was very happy with. Instead of focusing this blog post on how you can make your own version of The Chariot, I will try to explain my thought process throughout the design and build process, In other words, my hope is that after reading through this post, it will be clear why I chose the parts that I did. Continued…

Jon's line following robot: Usain Volt 2.0

Posted by Jon on 4 May 2015
Jon's line following robot: Usain Volt 2.0

Like other developers and engineers here, I made a robot for the LVBots Line Following Contest. This post describes my robot, Usain Volt 2.0, and details some of what I was thinking when I designed it. If you want to know more about the competition rules and how it was judged, see the LVBots line following rules. Continued…

David's line following robot that learns the course

Posted by David on 1 May 2015
David's line following robot that learns the course

Several people here made robots to compete in the recent LVBots line following competition. The goal of the competition is to make an autonomous robot that follows a line on the ground as fast as possible. I made a robot called LearnBot for the competition. LearnBot is able to learn the line course on the first lap and then use that information to its advantage on the second and third laps. Continued…

Video: LVBots April 2015 line following competition

Posted by Ryan on 29 April 2015
Tags: lvbots

LVBots held a line following competition at Pololu on April 16th. The goal was to make an autonomous robot that does three laps of the course the fastest. Seventeen robots faced off in a head-to-head double elimination tournament. The video above shows the robots in action and the full results of the contest.

Ben’s Mostly Red Racer won the line following competition for the second time in a row with an average speed of 1.2 m/s, but the competition was more fierce this time. Brandon secured second place with The Chariot, which had an average speed of 1.17 m/s and had a best course time that was only 0.7 seconds slower than Ben’s.

There were also some fun exhibition robots. Kevin made a hovercraft named Full of Eels that was able to sometimes follow the line. Kevin and Jeremy made The Next Level, a line follower on top of a line follower.

We will update this post with links to posts about the individual line following robots as they are published over the next couple of weeks.

Are you in the Las Vegas area? Check out the LVBots Meetup page to get involved.

New products: 40×7 mm wheels

Posted by Ben on 22 April 2015
Tags: new products
New products: 40×7 mm wheels

We now have 40mm-diameter wheels (available in black, red, and white) in the same thin style as our 32×7 mm wheels, which help fill the void between those and the 60×8 mm wheels that were previously our next size up.

Black Pololu wheels with 90, 80, 70, 60, 40, and 32 mm diameters (other colors available).

Like the rest of the Pololu wheels, the 40×7 mm wheels press-fit onto the 3mm D shafts on many of our motors, including the micro metal gearmotors and mini plastic gearmotors.

Pololu 40×7mm wheel on a micro metal gearmotor.

For more information, take a look at one of the items listed below, or check out all the Pololu wheels category page for more options.

Zumo 32U4 kit assembly video

Posted by Ben on 21 April 2015

A customer of ours who is a software engineer in Seattle made this detailed video showing how to assemble the new Zumo 32U4 robot kit. Thanks for sharing it with us, Jamie!

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);
  }
}

Video: Zumo 32U4 Robot Example Projects

Posted by David on 9 April 2015

We have a new video showing several projects you can do with a stock Zumo 32U4 robot. The Zumo 32U4’s motors, encoders, line sensors, proximity sensors, accelerometer, gyroscope, LCD, LEDs, and buttons make it a versatile robot that can be used in a wide variety of projects. The ATmega32U4 microcontroller on the Zumo 32U4 robot can be programmed in C++ from the Arduino IDE.

All of the projects shown in the video use unmodified, stock Zumo 32U4 robots (except for the Zumo driving on the refrigerator, which had strong magnets taped to it). However, you can open up even more possibilities by adding your own electronics to the Zumo 32U4. The FuzzBot, Pixy Pet, and this smartphone-controlled tank are some example projects by our customers that involved adding hardware to our older Zumo Robot for Arduino.

The source code for many of the projects shown in the video is available as examples in Zumo32U4 library, and we are working on adding more of them. Check it out, and get some ideas for a cool Zumo 32U4 project!

New product: Sharp GP2Y0A60SZLF Analog Distance Sensor

Posted by Ben on 9 April 2015
Tags: new products
New product: Sharp GP2Y0A60SZLF Analog Distance Sensor

We are now offering Sharp’s GP2Y0A60SZLF analog distance sensor by itself. This is a great sensor with a wide 4″ to 60″ (10 cm to 150 cm) detection range and a high update rate of 60 Hz, but it requires additional components to use and has a non-standard 1.5 mm pitch. You can use this sensor with our compact carrier boards to make a complete sensor module, or you can get our carrier boards with the GP2Y0A60SZLF already installed.

For more information, see the GP2Y0A60SZLF product page.

Looking for Wixel feedback

Posted by Ben on 3 April 2015


Looking for Wixel feedback

PeterPan, an active member of our forum, recently started a thread asking other Wixel users to push for us to get Wixels FCC certified. The Wixel is getting to be one of our older products, so it is due for some updates, too (e.g., our new USB products have moved on to Micro-B connectors). We realize many of our customers do not necessarily want to publicly discuss their projects, so if you do not feel like participating in the forum thread, please feel free to contact us directly about your thoughts on FCC certification and other ways you would like to see the Wixel improved.

New Products

Pololu Wheel 40×7mm Pair - Black
0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Straight, Red
Free Circuit Cellar magazine April 2015
0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Straight, Blue
Sharp GP2Y0A60SZLF Analog Distance Sensor 10-150cm
0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Straight, White
0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Straight, Yellow
AMIS-30543 Stepper Motor Driver Carrier
Pololu Wheel 40×7mm Pair - Red
0.100" (2.54 mm) Breakaway Male Header: 2×40-Pin, Right Angle
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