Running a DC motor from the Arduino Using the Creatron Economic Starter Kit

I’m teaching a Critical Making course and a question came up regarding how to run a DC motor from the Arduino. It was a bit tricky to get figure out how to do this using the parts in the Economic Starter Kit that students were told to purchase from Creatron, our local purveyor of maker stuff. There were a couple of puzzles, how to use the parts we were given and which online tutorial to follow.

I played around a bit and here is my result. I used the tutorial from bildr, which I found via the page for my MOSFET transistor on Sparkfun.

Parts

Arduino Uno (Rev 3)
Breadboard
DC Motor
Switching Diode (1N4148, 75V, 100mA)
N-channel Transistor (FQP30N06L)
330Ω Resistor

Graphic

Image created using Fritzing

Image created using Fritzing

If I’ve muffed up the diagram, let me know.

Code

I used the code from the Adafruit tutorial on DC Motors.

/*
Adafruit Arduino – Lesson 13. DC Motor
*/
int motorPin = 3;
void setup()
{
  pinMode(motorPin, OUTPUT);
  Serial.begin(9600);
  while (! Serial);
  Serial.println(“Speed 0 to 255″);
}
void loop()
{
  if (Serial.available())
  {
    int speed = Serial.parseInt();
    if (speed >= 0 && speed <= 255)
    {
      analogWrite(motorPin, speed);
    }
  }
}

Things to notice or could go wrong.

1. Make sure the diode is going the right direction. If you’re not sure, try it both ways.

2. Make sure you are using a PWM (Pulse-Width Modulation) pin on the Arduino. In the code, it’s Pin 3 and that’s correct for an Arduino Uno

3. Make sure that bare wires are not touching.

Using git and github from PyCharm

In last week’s class, I demoed using Sourcetree to manage your repositories. I didn’t show how to use the features in PyCharm for the same purpose.

Here are a some screenshots that should help.

The first step is to set up your repository. You can do this through the VCS menu item.

PyCharm->VCS

 

When you select “Github”, you’ll get the following dialog box. You should use the URL for your own repository, not the original that I provided.


Screen Shot 2014-09-28 at 4.49.50 PM

 

The things that can go wrong.

  • You don’t have a git client installed. (Solution is to install on– Mac or Win.)
  • PyCharm can’t find your git.exe.  This is a problem on Window only.  A solution is on Stackoverflow. Make changes to your Settings for Git.
  • Can’t log in. Check your password.

Once your project is set up, you can use the following menu items to commit to your staging area, and push/pull to github.

Screen Shot 2014-09-28 at 4.39.30 PM

 

Things that can go wrong.

  • You don’t see these options. It means that the files that you are working on aren’t under version control. You’re working on the wrong directory.
  • You can’t push. It could mean that you didn’t commit before pushing. Commit first to your staging area and then push.
  • You can’t push. It could mean that your code is out of date. Pull first. Resolve any conflicts. Commit and try pushing again. (If your partner is working at the exact same time, you might have to do this more than once.)
  • You can’t see your partner’s changes. Check that you are both working from the same URL on github.

 

If you want to learn more about git, read this introduction to git concepts. There’s also a 15-minute hands-on interactive course from Codeschool that teaches the command line version of git. It will provide a solid foundation, but goes way beyond what you need to know to get Assignment 1 done.

Percentage Women Directors in Canadian Tech Companies Not Exceptional

Abstract

According to a recent report, only 15.9% directors of Financial Post 500 are women. When Crown corporations are removed, women make up only 10% of directors. The percentage of women directors in Canadian tech companies is slightly higher (16.1%), but when the boards of multinationals are excluded this figure falls to (11%), which is consistent with other sectors. Blackberry and Open Text have high representation, 28.6% and 37.5% respectively, but four others have no women on the board. Implications and remedies are discussed. Continue reading

The 80% Mom

One thing you said haunts me still. When I asked about motherhood, you said that children don’t need as much as you gave. “Eighty percent is probably plenty.” I was shocked by your words. Did you regret having given so much of yourself? Now, those words seem like a gift. A way of offering me a model of motherhood, beyond even your own example.

I first read this about a year ago and it really struck home. It comes from an open letter by Karin Cook to her mom who had passed away from cancer many years before.

Continue reading

Call for customers for Introduction to Software Engineering

It’s that time of year again, when I’m preparing to teach Introduction to Software Engineering at UofT. This will be my third time teaching the course and I have more students than ever, almost twice as many as last year. As part of this course, third-year students in computer science work in teams to implement a software application for a client. Consequently, a lot of the preparatory work is finding clients. Our clients have been non-profits, social enterprises, and schools that needed some software built. Here are some Q&A to help you decide if this is a good opportunity for your organization.

Continue reading

Climate Change Drives Startup to Hard Drive Farming

A blog post on Backblaze’s web site shares stories from employees, friends, and families about how they participated in a “hard drive farming.” In this scheme, they purchased external hard drives two at a time from retail stores and sent them to Backblaze to help the company survive a worldwide hard drive shortage. Although the stories are engaging and the images are amusing, underneath it’s a story about how climate change affected a Silicon Valley startup’s business plan. The hard drive shortage was caused by unprecedented flooding in Thailand, which produces about half of the world’s hard drives.

Continue reading

Seeking customers for student projects

I will be teaching CSC 301: Introduction to Software Engineering at University of Toronto this fall. The course is meant to teach software process for small teams, also known as agile. Students work in teams to complete a software project. I would like the projects to be for social enterprises to incorporate service learning into the course. As a result, I am now looking for non-profits or social enterprises who need some software built. Here are some Q&A to help you decide if this is a good opportunity for you.

 

Continue reading

Winners of the Singular Source Contest

After careful consideration and discussion, we have chosen the winners of the Singular Source Short Story Contest.

We received a total of eight submissions to the short story contest, which made for a small slate of high quality candidates. There were no bad stories and every one was entertaining in some way. Every entry was read by all three judges independently. We subsequently met to discuss our assessments and to decide on a winner. (Actually, getting all of us together at the same time for a conference call was the most difficult part of the process.)

Continue reading

Wearing the Vibram Five Fingers

“Are they comfortable?” is the first question that people ask when they see my shoes.

Surprisingly, it’s not an easy question to answer. I’ve been wearing my Vibram Five Fingers for about two months now and they garner a lot of attention. I have had many conversations with friends and strangers about my shoes, so let me share my story.

Continue reading