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…

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…

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…

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…

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.

Here are posts about some of the robots in the contest:

• Jon’s line following robot: Usain Volt 2.0
• David’s line following robot that learns the course
• Brandon’s line following robot: The Chariot
• Jeremy’s line following robot: Zumo Slim
• Nathan’s line following robot: Suckbot
• Grant’s line following robot: Pinto
• Claire’s line following robot: Oddish
• Amanda’s line following robot: Newbie
• Paul’s Wixel-based line following robot: Two Point Four

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

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.

Related products

	Pololu Wheel 40×7mm Pair - Black
	Pololu Wheel 40×7mm Pair - Red
	Pololu Wheel 40×7mm Pair - White

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!

Related products

Zumo 32U4 Robot Kit (No Motors)

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);
  }
}

Related products

	DRV8825 Stepper Motor Driver Carrier, High Current
	A4988 Stepper Motor Driver Carrier
	A4988 Stepper Motor Driver Carrier, Black Edition
	DRV8824 Stepper Motor Driver Carrier, Low Current
	DRV8834 Low-Voltage Stepper Motor Driver Carrier
	A4988 Stepper Motor Driver Carrier with Voltage Regulators
	A-Star 32U4 Prime SV microSD with LCD
	Stepper Motor: Bipolar, 200 Steps/Rev, 35×36mm, 2.7V, 1 A/Phase
	170-Point Breadboard (White)

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!

Related products

Zumo 32U4 Robot Kit (No Motors)

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.

Related products

	Sharp/Socle GP2Y0A60SZLF Analog Distance Sensor 10-150cm
	Pololu Carrier with Sharp/Socle GP2Y0A60SZLF Analog Distance Sensor 10-150cm, 5V
	Pololu Carrier with Sharp/Socle GP2Y0A60SZLF Analog Distance Sensor 10-150cm, 3V
	Pololu Carrier for Sharp/Socle GP2Y0A60SZLF Analog Distance Sensor, 5V
	Pololu Carrier for Sharp/Socle GP2Y0A60SZLF Analog Distance Sensor, 3V