Category Archives: Maker and DIY Electronics and Computer Projects

This is for adults and kids who enjoy doing things with open source and open hardware (Arduino, Raspberry PI, circuits, etc.) Most of this is personal interest that I have that do not relate directly to my career.

Designing and Building a Self-Driving Car – Part 4

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Topics:  The many lessons of Pulse Width Modification or “Where have I seen this before?” Thoughts on Motor Speed and where to look for inspiration for a project.

This blog will be about the many lessons one learns throughout his or her life – and boy! have I’ve learned many!  In college I took electrical and electronics engineering courses, but one of the biggest lessons learned were not about resistors, capacitors, or Kirchhoff’s Voltage Law, or transistors; it was: ” You will forget what you learn quickly, if you don’t apply it in practice.”  This is the lesson that I intend to instill in my child throughout this project.

My “Parent’s Guide” tip is to create a project that will continuously reinforce the concepts that you will be using for the project.  The best way, in my opinion, to do this is to have a project that will last many months (or in years in my case).  Take a detour now and then to do a science fair or demonstration in from of the grandparents, science clubs and assortment of friends; in between boy scouts, or girl scouts, baseball, volleyball, tennis, swimming, or the myriad of activities children do throughout their lives, you need one project that is consistent and continuous and big for which they can take into college or whatever the next big step in their lives will be.

Learned about pulse modifications throughout my education.  First in an electronics lab course in 1993, and again in 1997 and 1999.  When I began working on the autonomous car project with my child, we began working on the PWM circuit for the electric motor that was to go into the car.  I forgot how it worked or what it would take to build this circuit.

The morale is working on a project such as this she help to continuously reinforce concepts of STEM throughout a child’s life and should not just be about getting it done!

We decided to create multiple prototypes (4), varying in difficulty, size, configuration and purpose.

Prototype 1:  Will be the an simplified Arduino and RaspberryPi prototype built for the sole purpose of controlling a DC Motor and a Servo with OpenCV and a RaspberryPi camera.  It’s a non-functional RC model.

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Prototype 2:  Will be a workable RC Car that will do everything that Prototype 1 will do, but will have a Brushless motor with ESC and will move.

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Prototype 3:  Will be a 3D printed model designed in Bender and then 3D printed.  This prototype will better emulate an “actual car”.  It will have all the essentials such as a transmission, steering, suspension, differential, axle, etc.  It will not have all the other things a car has that have nothing to do with power, acceleration or steering.  I will be a working model with an actual brushless motor, computers and microcontrollers.  It will not have cameras, but will be operated by a dataset from actual road video.

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Figure 1:  Blender open source design software

Prototype 4:   An actual gasoline car rebuilt into an electrified self-driving car.  My hope is to rebuild an old Geo Metro.  But the chances are a little small at this point, because Geo Metros all over the country are being snapped up to convert to electric.  The advantages of rebuilding an electric car using a Geo Metro are:

  1. They’re cheap.  Many have bad engines which make them even cheaper.  You could find one from $300 to $1500.
  2. They’re lightweight.  Geo Metros are three cylinder and don’t have all the stuff that weights modern cars down.
  3. The shape is conducive to the space you would need for an electric car.  Since the car that I’m building will also contain computers and other mechanisms to make it self-driving, the hatchback is particularly attractive.

 

Chevrolet_Metro_hatchback_rear

 

Parent’s Guide to Designing and Building a Self-Driving Car with Their Kids – Part 3

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“It’s not the destination, it’s the Journey…” 

I suspect building a full-size self-driving car seems like a momentous task – and it is.  But a few things we have going for us.  As I stated in my previous blog, autonomous (self-driving) cars have a lot of the STEM aspects you want to instill in your child – math, science, electronics, and technology.  So even if you don’t finish this, those subjects will take your child far.

A few things I would recommend is building a design for you car.  The cheapest way of designing anything is using a Computer-Aided Design (CAD) software.  For me, this is Autodesk® AutoCAD® 2017.  It’s a great software package, but a little on the pricey side.  There are also plenty of open source CAD software packages available.  The nice thing about AutoCAD is that i comes with an add-on called Autodesk EAGLE, which is a electronics schematic design tool.  Inevitably, there will be some electronic circuits required to build the prototype and eventually the actual car, so having an electronics design tool will be very helpful.

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Autodesk EAGLE, a electronics design tool

I alluded this earlier in one of my blogs, but you will want to build a prototype that makes it easier for kids to learn about the curriculum and about the subject matter involved. A prototype has a smaller budget an can be a much smaller than the eventual final product.  In my case I took apart one of my child’s toys and hooked it up to a RaspberryPi and Arduino (see Part 2 for more info).

Having a cash budget and setting design limitations on the car will take out a some of the risk of a venture such as this.  For instance, our stated goal was to create a car that would not have an occupant riding inside of it, nor would it be on any public roads. This would not require us to get specific permits or spend heavily on safety features of the car. Before building anything large, my recommendation is to have the following:

  1. A budget.  My budget is going to be around $15,000 adjusted for inflation.
  2. A goal statement or what you want to achieve that makes the project a successful learning experience.
  3. design goals.  The must haves to achieve the goal you want.
  4. If you want to get really crazy, an actual project plan.

We actually plan to create multiple prototypes, as our skills increase, so will the quality and “coolness” of our design.  This RC car we plan to use for our second prototype:

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The body of the prototype II car will a Porsche.  Prototype I is almost done 🙂 !

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The internal frame of prototype II car.  Once completed, it will have cameras, computers, and motors.  There will be other devices as well to help with autonomy.

Parent’s Guide to Designing and Building a Self-Driving Car with Their Kids – Part 2

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“The two biggest challenges with this project is: 1) Getting your kids more interested in the project over their video games. 2) Convincing your child’s science teacher they did most of the work for the school science fair”

Before I start delving into the technical rigors of building a self-driving car.  I want to talk about kids.  As parents, we want our kids to be excited about things we get excited about.  When I thought up this project, I realized it was above what a fifth grader could do.  A self-driving car involves a multitude of technical subjects:  Advanced calculus, statistics, probability, linear algebra, deep learning, machine learning, electronics, computer science, telemetry, data science, mechanics, physics,…These are subjects kids are not expected to be good at.  But, I thought to myself  “It’s about the Journey…”.

As a parent, I want to expose my kids to STEM (Science, Technology, Engineering, Math).  This project is STEM³, meaning, it’s several factors above what is typically taught in grade school level STEM curriculum.  So how do you incorporate this into a child’s STEM education without frustrating your child and yourself in the process?

Divide things up into simpler lessons

So when my child and I started thinking about building a self-driving car, we started small.  We converted a radio controlled car into a self driving robot using the following components:

  1. Raspberry Pi 3 microcomputer.
  2. Arduino Microcontroller
  3. OpenCV computer vision software.
  4. Chassis of an old RC car.
  5. Electric 9V Motor

We then said, “What are the major components that a self-driving car would need”.  What we listed were:

  1. A Motor
  2. Steering
  3. A computer
  4. A camera

Doing our research into companies like Waymo, Google, Volvo, Tesla among others who are investing millions into autonomous technology, we began learning that among these pioneering companies are a community of tinkerers who are using open source code and open hardware to build autonomous RC cars.  Many of whom are blogging about it.  To learn more about these communities, I recommend the blog series. Becoming Human AI.  

With then focused on specific topics, that children could research and learn about.

  1. For the Motor: Pulse Width Modification.
  2. For the Steering:  Controlling sweeper servo moters.
  3. For the Computer:  Programming Raspberry PI with Python.
  4. For the Camera:  Using OpenCV for image processing.

School Science Fair Skepticism

When we attended my child’s science fair, we had spent weeks going over Pulse Width Modification, which is a way to control an electronic motor speed and building a sweeper motor for our prototype RC autonomous car.  We stuck on a Raspberry PI 3 computer which is basically a very cheep microcomputer that you can program and load up with an open source software package called OpenCV.  OpenCV  can detect images from a camera be recognize what that object is at least detect things in an image.  When we were done our science fair project looked like this:

 

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We spent weeks putting this together, and I made certain my child understood each component in the car and had the knowledge to talk about it.  What I quickly noticed was among the baking soda volcanoes, and the dyed flower petal experiments, was a lot of skepticism that a fifth grader could put something like a “self driving robot”-thingy  together.

My child put the poster together and did all the calculations as I stood by and asked “So what can you include from those findings?”  The scientific method, which is the most important tool in science, was reiterated throughout the experiment:

  1. What are observations?
  2. What is your hypothesis?
  3. What methodology did you use?
  4. What is your experiment?
  5. What were you conclusions (what did you learn)?

This is what needs to be the basis for a child’s work in STEM projects in order for him or her to learn from the successes and failures of doing science and technology.

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The picture above is my child’s science fair poster.  We worked pretty hard on it.  But my child did all of analysis and calculations and took all of the notes and typed it up.  I gave him a test to make certain that he understood everything.  The goal wasn’t to win (he didn’t) it was to get him interested in science and technology and show him that there are others that are excited as well…And many people were!

 

 

 

Parent’s Guide to Designing and Building a Self-Driving Car with Their Kids – Part 1

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I was never really a “car” guy.  I always saw them as transportation from point A to point B.  I’ve abhorred walking into a car dealership to negotiate car purchases; and as a parent, keeping my car clean seemed like an constant battle.  Driving long distances, even if the car was clean, was especially arduous for me.  America is a huge country, so driving from my home in North Carolina to South Carolina or Tennessee is a five to seven hour odyssey without any of reward or enlightenment.

However, I was always enjoyed NASCAR (being from North Carolina), and I enjoyed watching YouTube videos of DIY rebuilders who take wrecks of cars and give them a new life.  So when I first learned about self-driving cars and the amount of tech and data that goes into making these autonomous machines, I started to take notice…

In this series, I will be discussing all the successes, failures and lessons learned building a life-size self-driving car…with my sons.  Subscribe and follow me on my blog to see how we’re doing.  I suspect it will be years before we are done (or give up) with it all.  It’ll be a lesson on how to build it, but also how to get your kids excited by a challenging STEM project.

Stay Tuned!!