Today we have added an extra dimension to this site. The prior blog mentioned that after a few years of enjoying DC motors some people with a technical “bent” begin to feel a draw toward robotics. I went on to explain that robotics will draw mechanical engineers, electrical engineers, and computer programmers together since it requires the skills of all three to bring to life a robot – whether for educational purposes, or a personal robot, or an industrial robot. As such, I have added something to the title of this website now calling it “Motors and robots are fun.”
I trust that you have enjoyed the content on building direct current (DC) motors and even the brushless DC (BLDC) motors on this site. All of the videos have provided actual, real-working motors that my children and me have built. The directions for building a basic DC motor on this site is free and can be downloaded for any boy scout, girl scout, or Science Fair participant.
Looking back over the past two years, I have noticed that robotics has crept into my writing so that is the reason why I have added it to the website. As a STEM-oriented dad, I have seen my own children move into careers where science, technology, engineering, and math are required and am glad to see them earn an above average salary. Two are in banking using spreadsheets and calculations, one is a materials engineer, and one is a mobile app developer. My only daughter is a dancer/tumbler/aerialist performer on a cruise ship and has nothing to do with STEM subjects (even though she was admitted to a major university as an engineering student!)
So, today marks a change of sorts. Hopefully, I’ll have additional content that you will like. If it piques your interest, you may invest in some of the robots that I plan on mentioning and videoing for you on this site. For instance, one of the more interesting robots is the Sphero 2.0 robot. There are now four versions rolling around homes, playgrounds, or obstacle courses today. There is the first Sphero 1.0, followed obviously by Sphero 2.0, then Sphero SPRK, and the latest which I observed a few weeks ago called the BB-8™ App-Enabled Droid™.
On the left is the BB-8 App-Enabled Droid made by Orbotix who has also made the other versions of the Sphero robot. Also, Orbotix makes a robot called Ollie which is a cylindrical robot that moves similarly to Sphero although Sphero is a sphere not a cylinder.
Orbotix’s definition of Sphero is that it is a “ball gaming system.” It’s a white-shelled waterproof ball that encases a robot that can be controlled by iOS or Android phones or tablets.
Sphero can be controlled using a number of free apps (I use the Sphero app and the Sphero Companion app from the Google Play store). It can glow more than 16 million colors and is recharged via an induction charger (the same technology used to power an electric toothbrush). Three hours of charging will give an hour’s worth of play.
You can control the ball up to 15 feet away and even use the ball’s in-built accelerometer to control action on-screen in the fun Exile game. Other apps include Draw & Drive, where the Sphero will follow the direction of whatever you etch on-screen; and Golf where your phone becomes a virtual club.
The BB-8 is a unlike any other robot. It has an adaptive personality that changes as you play. Based on your interactions, BB-8 will show a range of expressions and even perk up when you give voice commands. The person controlling BB-8 set it to patrol and we watched it explore autonomously around the room. He also said that he could create and view his own holographic recordings.
- An easy to use robotic ball that is lots of fun. The SPRK (Schools/Parents/Robots/Kids) version adds a level of complexity. It is a see-through robot to give kids an inside look at how it works.
- A range of apps boost interest in the robot and helps students see the relationship between
- The cost of $125 may be too costly for some. I got mine from eBay using the “Buy it Now” for $80.
Our view: Sphero is a remote-controlled robot that is a fine first robot for both children and adults alike. It will provide hours of fun, both on land and in the water.
Quote for the Day: “The pessimist sees the difficulty in every opportunity; the optimist, the opportunity in every difficulty.” — L. P. Jacks
The previous post mentioned that we would show typical applications or appliances where motors can be used. Before we list a few, we need to define what is meant by a “universal” motor. A universal motor is one that can use either direct current (DC) or alternating current (AC). Most, if not all, motors on this site use direct current to power them. A universal motor uses a a different type of armature winding. People will generally refer to a universal motor as a series motor because the armature winding is connected in series with the field winding. If you go to the top of the page and look at videos of Advanced Motor #3 and Advanced Motor #4 you will see how the armature winding is connected in series with the field winding. This means it can handle direct current or alternating current.
One of the problems with the universal or series motor is it does not have very good speed regulation because the speed of the motor varies as the load is increased from no load to complete load. One of the positives about the series motor is that it creates higher torque as the speed decreases. It can also be used at high speeds. As such, these features permit the motor to put a large amount of power in a small package.
Here are some typical applications of a universal or series motor. How many others can you name?
- Robot motors
- Kitchen mixers
- Electric shavers
- Electric wheelchair motors
- Vacuum cleaners
- Hair dryers
- Food processors
- Automobile starter motors
- Golf cart and electric car motors
Quotes for the Day – and they said it couldn’t be done:
“Everything that can be invented has been invented.” — Charles H. Duell, Commissioner, U.S. Office of Patents, 1899
“I think there is a world market for about five computers.” — Remark attributed to Thomas Watson, chairman of the board of IBM, 1943
“There is no reason for any individual to have a computer in their home.” — Ken Olsen, President of Digital Equipment Corporation, at the Convention of the World Future Society, 1977
It has been a rather long time since we reviewed what a student can learn from assembling a small, direct current (DC) motor in a classroom or home school setting. This post does not include the simple DC motor known as the Beakman’s motor. The Beakman’s motor is a very simple motor that does show an interaction between a magnet and an energized coil, but it does not have material (such as an iron armature) inside the coil to improve performance of the motor. Also, with the wobbling in its “cradle” it shows it is not a precision built piece of equipment. However, despite these misgivings some of the basic principles are able to be taught and learned (see Figure 1).
Here are few concepts that would be good to integrate in any discussion about DC motors:
- A key tenet of a motor is magnetism. It is a force that attracts and repels. A magnet has a magnetic pole at each end. One is called the north (N) and the other end is called the south (S) pole.
- Like poles repel, e.g., a N-end of one magnet will push away from the N-end of another magnet. Opposite poles attract such that one N-pole of one magnet will pull toward the S-pole of a different magnet.
- The Earth is a giant magnet that has a north and south magnetic pole. The poles seem to wander but it happens very slowly so compasses are able to help in navigation.
- An electromagnet is made by wrapping a wire that carries an electric current around an iron bar. This ends up being a magnet that can be turned on and off at will.
- An electric motor uses the attracting and repelling properties of magnets to create motion. An electric motor contains two magnets. A permanent magnet (also called a fixed magnet that does not spin) and a temporary magnet. The temporary magnet is a special type of magnet mentioned above, it is called an electromagnet.
- The permanent magnet has a magnetic field all the time but the electromagnet only has a magnetic field when current is flowing through the wire.
These are the main concepts necessary to have a student understand the background of a small, DC motor. In future blogs, we will talk about applications of this type of motor.
Quote for the Day: “If you cannot do great things, do small things in a great way.” — Napoleon Hill
This past week Mr. Scott Bailey invited me to speak to three of his engineering classes at Scott County 9th Grade school. I’ve known Mr. Bailey for over four years and he is the finest engineer-turned-teacher I know. He is knowledgeable, supportive and helpful to his students, volunteers for multiple events, and really wants to see his students reach success in school and later in life. He has become a very good friend. Since we met two days before school was out for the year this was a treat for his classes and some brainy students were able to walk away with a literal “treat” of a bag of yogurt-covered pretzels or a Hershey candy bar.
Most of you know I love to speak about small DC motors. Of course, this was the start of my discussion with the students, but then we branched into how motors and servos are used for a few robots, and we wrapped up our time together in each class by encouraging the students to consider a STEM career. I found a few statistics from an article written by Steve Crowe, managing editor of Robotics Business Review, regarding high school seniors and STEM careers:
- Only 16 percent of American high school seniors are proficient in mathematics and interested in a STEM career
- Only 30 percent of high school seniors who took the ACT test were cleared for college level sciences
- Average income for a STEM career: $77,880/year
These facts were a wake-up call to most students, but three years until they would become a senior seemed like eternity right now.
This year Mr. Bailey had some bright students as evidenced by some excellent end-of-course assessment scores. Most of his students are planning on pursuing engineering – some are interested in architectural engineering, chemical, aeronautical, electrical, mechanical and civil engineering. I love interacting with the students and get a good sense of what inspires them and what turns them off. One of the things that got them going was a few riddles. These were riddles that required them to ‘think outside the box.’ These were riddles I had learned when we studied lateral thinking in college. I tried to explain that some people have a tendency to think this way and those that didn’t today can learn to do so in the future. This ability to think on a deeper plane helps tremendously with problem solving – to look at a problem from different perspectives. It’s all a part of the scientific method.
It was a joy speaking to these three classes of 9th graders. Despite it being near the end of the school year they were attentive and asked good questions. In the last class, the students didn’t want the class to end. Not only did this demonstrate their interest in considering a STEM career, it gave me hope this millennial generation will be well prepared to carry on and improve on the technical careers that are available today and those careers that have not even been named yet.
Quote for the Day: “The greater danger for most of us is not that our aim is too high and we miss it. But that it is too low… and we reach it.” — Michelangelo, 1475-1564
My sons and daughter went in together and gave me a wonderful Christmas gift this year.
It is called a WowWee MiP robot. The MiP stands for “Mobile inverted Pendulum.” The best I could figure is that it is another way to say self-balancing. This little robot (~8″ tall) works like Dean Kamen’s Segway vehicle and uses a gyroscope to keep it balanced.
WowWee does a nice job of having the robot work right out of the box if you have four (4) triple-A (AAA) batteries available. My sons and daughter bought me the KOHL’s Special Stunt Edition with a Stunt Teeter Ramp.
On the outside of the box it had the battery requirements and how to install them. Everything went down just as expected.
After turning it on you will see various modes indicated by the color of of LED on the front of MiP. The default is blue which means is uses what is called GestureSense Technology. You use your hand to make the robot move forward, backward, turn right or left, or stop. It doesn’t take long to learn how to make the robot work in this mode. Here is a video from DadDoes.com to give you a flavor for how the robot works.
Some people think the Gesture mode is good basic training and then will move on to Stack mode where you have to install a tray accessory to the front of MiP. In this mode you have a few seconds to stack a heavy object or several light objects onto the top of the tray. Of course, you can use this mode without the timer.
All of the other modes – cage, tricks, roam, dance, and tracking require you to pick up MiP and turn the right or left wheel until the mode indicator changes color to the mode you want to use.
In addition to using the above modes, you can download the free app to access features or turn your smartphone into a remote control to play games or have MiP dance or in my case, roll up to the Stunt Teeter Ramp and go over it without having it fall down!
The key about using the free app is to be sure you have the right system requirements ahead of time. For instance, I bought an Android smartphone in January 2014 with Android 4.1 on it and it could not handle the app. For an Android phone you must have Android 4.3 or later. It was a bummer not being able to use it until one of my geek sons allowed me to use one of his Android phones running Android 4.4. The download was quick through Google Play and then the fun really began. Here is just a short glimpse of controlling MiP via the Android app.
(For Apple you need to have iPhone 4s or later, iPad 3, iPad Air or later, iPad mini, iPad minii Retina or later, iPad touch 5th generation, iOS 7 or later. Here is the listing of device compatibility.)
Overall, I had hours of fun playing with MiP and intend on getting to the point to fully utilize its capabilities. There is an option where you draw a path on the screen and MiP will follow it. As MiP moves along the path the app shows a virtual MiP so you can follow its progress on the screen.
If you’re a dad like me, a gift like this will be one for the ages.
Quote for the Day: “The two most important days in your life are the day you are born and the day you find out why.” – Mark Twain
Today is Christmas Eve 2014. What a wonderful time of the year when family and friends have the opportunity to visit, renew friendships, and find out just what happened over the past year. It is also a time of remembering and celebrating when Jesus was born. For those that have put their faith in Him, He has become their Savior. Many biblical historians believe He was born earlier in the year, around the April time frame rather than December. I’m not really hung up on the specific date, but am glad we take the time to understand what He has done for us, especially in the area of giving.
I’m always on the lookout for various DC motors and motor kits. Well, today I had the opportunity to build a brushed DC motor designed and sold by Darcy Whyte from http://inventorartist.com/. He is an amazing person who loves mixing technology with art. Once you hit his site you will see what I mean.
If you are looking for a site that has interesting inventions such as a clock made of a record, a line follower robot, learning about Arduinos, and many more cool projects, this is the site for you.
He calls this kit a Dinky Motor kit that he sells through his store. Here is a link to his instructional video. I followed the video and had my Dinky Motor running in one hour. The great thing about Darcy’s kit is that he has laser cut all the parts and each part fits perfectly. You can use a touch of glue if you want to, but in reality the parts press together so well it is not necessary to glue any of them.
Below are a few pictures and description of the build:
Basic parts of the Dinky Motor kit (notice the rare earth magnets)
(L to R) Frame of the motor, armature parts pressed together
Frame disassembled so the brushes could be added
Frame of the motor with the brushes installed and the completed armature (with commutator)
Added a power supply and a door bell to complete the circuit which made it easier to start and stop the motor.
Once all of the parts were assembled, the rare earth magnets were installed (this can be a little tricky), and batteries were wired up, it was time to press the door bell switch to see the armature start move. I did all of the above and pressed the button, but nothing moved – it just sat there!
I knew it wasn’t the batteries or the door bell button since I just took them off another DC motor I took to my son’s wedding a week ago to show some homeschoolers about DC motors.
So, I checked the orientation of the rare earth magnets. They were installed correctly. Next I looked at the rotor and commutator assembly. All of the varnish had been removed from the commutator. That left the brushes. If you remember from other motors I have written about, the brushes are the most difficult to build for brushed motors (that is why I like to make brushless DC motors, or BLDC for short). Sure enough, I had not removed enough of the varnish off the copper wire on one of the brushes. Once I used the sandpaper on one of the brushes and then carefully pressed the armature assembly in place, the Dinky Motor spun up and ran like a top. You can see the motor running in the 20 second video below.
All in all, a great DC motor kit. You can tell that Darcy has had several versions developed and kept improving it each time. I love the simplicity, the attention to detail, the video instructions, and the homemade appearance of the motor. Once you get your kit, you can plan on about an hour to assemble and troubleshoot the motor. One thing you must keep in mind is that you should plan on about (3) AA batteries to power the motor – just so happened I had an extra battery enclosure that I used. Suggestion: you might want to get one of the battery holders from Radio Shack ($2.99 USD) or make a trip to a local electronics shop. This was an enjoyable build and I trust that you will enjoy it as much as I did. Merry Christmas to all.
Quote for the Day: “I am enough of an artist to draw freely upon my imagination. Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.” — Albert Einstein
Today was one great fall day. The morning temperature was in the 40s and gradually it warmed up to the high 60s. After reading the Bible, cutting the grass, raking the leaves and doing some other honey-do work around the home, it was time to build a Reed Contact Motor from Kelvin Educational products. This kit can be ordered from kelvin.com. Kelvin also has many other interesting science and robotic kits that you or your parents might be interested in ordering for a birthday, Christmas, or to provide something for you to do during a spring or fall break.
Although this instruction manual said it came from Farmingdale, New York, the parts list was written in millimeters (mm) and the dimensions were provided as if the kit was designed in the United Kingdom using 52,0 mm vs. 52.0 mm as seen in the United States. The reason I mention this is the author of the instruction manual used terms I was not familiar with like Mignon cell batteries, PMMA, Pillar drill, etc. A clever youngster can read the instructions and figure out how to measure and diagram the parts for drilling and sawing, but some of the above terms might through you off – that is why you might need an adult nearby.
Here are the main pieces that come in the plastic pouch that was shipped to me:
Kelvin Electronics Reed Contact Motor
This above photo shows the instruction manual, the plywood base, the copper wire, the acrylic side brackets, the reed contact, the pine coil holder/magnet rotor, battery holder, and various sundry items like the magnets, brass nails, and the set screw that you use to make the electromagnet.
The first few pages of the instruction manual give you the dimensions that are required to build the motor. Here is an photo of the components I put on the three main components.
The three pieces that need to be dimensioned prior to cutting
In order to build this kit you have to provide two different saws (one to cut the acrylic and one to cut the wooden base, rotor, and coil holder), two needle-nosed pliers, glue, masking tape, soldering iron and solder, and a AA battery. It took me about 2-1/2 hours to cut out the side supports (acrylic), the base, the rotor, the coil holder, glue the magnets to the rotor, and wrap the 30 feet of wire to make the electromagnet. Here are a couple of photos of the finished product before testing.
Close-up of the reed switch (note how the reed switch was soldered to the brass nails)
Top view of the completed motor (note how the reed switch is lined up with the magnet)
Side view of the completed motor
Once the motor was complete and pictures taken, the next step was to insert the battery to see if the motor would start. I carefully put the battery into the battery holder and … nothing happened. What went wrong? I had checked to be sure the polarity of the magnets were correct before I glued them onto the rotor. Once again I checked to be sure I had wired it all correctly. As I started looking at the rotor and moved the motor slightly it started to run! Immediately, I knew what had happened. In order to make this motor run you have to have the magnets be a little off center in order to pull onc part of the reed switch away from the other part of the reed switch. Since I had a little “give” in how the rotor lined up, it was easy for it to automatically move to the right spot on its own. That is what is nice about most DC motor kits – most of the time you don’t have to make them perfect to have them run.
Here is a photo of the rotor spinning merrily along.
Here is the video of the motor as well:
I get a lot of enjoyment making these DC motor kits and hope you do as well. This BLDC kit cost around $7.95 plus I had ordered additional motor kits to save on postage. Now that it is getting colder it would be a good time to start making a few DC motors for Boy Scouts, Girl Scouts, science clubs or even enter the next Science Fair at your school. Again, it was a great fall day!
Quote for the Day: “Do what you love and what you love will reward you.” — Dave Martin
Last Saturday I was invited to speak at a local Geek Conference – the second annual Geek Conference. The theme of this conference revolved around proving the existence of God. It was an all day event and the speakers were geeks – two mechanical engineers, a chemical engineer, an electrical engineer, a computer programmer, and a mechanical engineer turned pastor. The pastor has a heart for technology and for geeks. In general, geeks are somewhat maligned in society and he wants to reach out to them to show them how important they are to society and especially to God. The conference was informative and thought-provoking as well. During the conference we had the opportunity to win prizes by figuring out mathematical and word puzzles. All in all, it was a great day.
During my presentation, I sought to explain four proofs for the existence of God. As an engineer, what really had the most effect on me was a three-word answer to the existence of God – “there are laws.” As most of you know, I have been building small DC motors for a long time, since I was a child. What has intrigued me the most is how the motors work. Simply, it is magnetism, the idea of attracting and repelling, Yes, you can extend that to electromagnetism, electromagnetic induction (EMI), or back emf, but these all are related to magnetism. So, I attempted to prove the existence of God through laws – the laws of physics, laws of thermodynamics, laws of buoyancy, laws of morality, natural laws, etc. You can’t dispute that without these laws life as we know it wouldn’t exist. Bottom line is that if there are unchangeable laws it implies there must be a lawgiver and I proposed that lawgiver was God.
In demonstrating some of these laws, I used a kit I found from a company called Squishy Circuits. It is a company that was a spinoff from the University of St. Thomas located in St. Paul, MN. I first saw a TEDx talk by AnneMarie Thomas, an Associate Professor of Engineering at the University of St. Thomas, where she spoke about teaching circuits to younger students. The kit her company offers has a bunch of LEDs, a few buzzers, and a DC motor. So during my discussion I used the concept of squishy circuits to show how Play-Doh can be used as a conductive or non-conductive wire. One of the experiments included attaching a DC motor to the circuit. As you can see in the video (4th row down on the right with Matthew Schmidtbarr, a student researcher for Squishy Circuits) in order to complete the circuit, the motor must be put in the circuit in the right way. You can’t put the motor’s leads in one part of Play-Doh, it won’t run because the circuit is not complete. You can’t put the motor’s leads in each of the Play-Doh pieces and touch the Play-Doh together because it will cause a short circuit. These videos are informative and wished I had had these when my children were growing up while we were making DC motors. These would have been very good demonstrations at home and also the concept could be transferred so my sons and daughter could use them while speaking at the local and state 4-H Talk show.
The Geek Conference once again taught me that a person must stay flexible in learning and teaching new ideas and concepts to others. Be sure you keep an open mind.
Quote for the Day: “Do not go where the path may lead, go instead where there is no path and leave a trail.” — Ralph Waldo Emerson
This summer was just too busy. My children are growing up, playing sports – softball, basketball, and ultimate frisbee, getting married, and having children of their own. As such, Mrs. “Motorsarefun” wanted to see the boys play their sports, our daughter perform in the latest Distinguished Young Women program, and visit our new grandchild. Fall, winter, and spring do allow more time to write and reflect on things other than work, children, and grandchildren. It has been said that if you wanted to make time for it, you would. I have no excuse.
Did want to write a very brief history on DC motors since I have noticed that there are a lot of people that are looking for information on building DC motors, watching a few videos, and downloading the PowerPoint on how to build a fast DC motor. Not many have taken the time to visit the “History of Electric Motors” page. Thought I’d pen a few words about that.
If you have visited this blog much, you know that at the basic level electric motors convert electrical energy into mechanical energy. Mainly this is done by way of two interacting magnetic fields. One of the magnetic fields is stationary and the other magnetic field is attached to a moving part. DC motors have the potential for high torque, they are easy to scale down, and can be regulated or “throttled” by adjusting the supply voltage. Surprisingly, DC motors are not only the simplest they are the oldest electric motors. Also, they are simple to build.
In the early 1800’s there were several inventors that discovered principles related to electromagnetic induction (EMI). Some of these inventors were Hans Christian Oersted, Carl Friedrich Gauss, Michael Faraday, Joseph Henry and William Sturgeon. By around 1820 Oersted and Andre Marie Ampere discovered that an electric current produces a magnetic field. This was a real breakthrough and it led to greater experimentation and innovative thinking for the next 15 years. After a lot of experimenting took place, the first, simple DC rotary motor was invented in a lab but not for commercial use.
One of our future blogs will introduce the first person that has been identified as the inventor of the electric motor.
Quote for the Day: “If you ask what is the single most important key to longevity, I would have to say it is avoiding worry, stress and tension. And if you didn’t ask me, I’d still have to say it.”– George Burns.
Sinotech USA produces some very good infographics. I love infographics because the person designing them must understand the key messages the company wants to portray. Sometimes an infographic includes comparisons of numbers based on years between the data presented. In other infographics, companies will bring in startling facts that can be substantiated and makes the reader sit up and reread the facts. This helps companies that make and use infographics to have what is called in marketing circles, brand awareness. The higher the brand awareness, the more likely the product or service will be bought from that company. A brand that is well known to consumers or to a majority of households is called a household name.
On this site we have examples of brushed DC motors and brushless DC (BLDC) motors. I have videos of each type and have discussed various kits or DIY (do it yourself) projects that you can build for both types. Today, I present an infographic from Sinotech USA that describes the difference between both types of DC motors. I trust you will enjoy seeing both types explained so well. For instance, the basic parts between both types are shown: brushed has a commutator, brushes, and an armature while a BLDC has a stator and rotor. In the second table, Sinotech discusses key differences between both types such as the brushed motors have brushes (duh) that wear out more quickly than the BLDC motors. Please note the infographics I put on this site are for educational purposes and I don’t receive any remuneration from Sinotech. I just like their infographics and will others in the future.
Quote for the Day: “Getting an idea should be like sitting down on a pin; it should make you jump up and do something.” — E. L. Simpson
To get a larger view of this infographic, click on it twice.