Category: BLDC motors

A New name for our site – Motors and Robots are Fun

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™.

ijgi_sphero_bb8On 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.

Here’s a brief video of my first attempt to get Sphero 2.0 activated and driving over the ramps that come with the orb. Sphero is very responsive and it moves differently on hardwood floors versus on carpets. I used an Android phone, downloaded the Sphero 2.0 app, searched for the Bluetooth connection, and when found was able to get the app working within 15 minutes. Here’s the video of the first run!




  • 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



A real “treat” for the end of the school year!

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.


Speaking about DC motors and robots

Speaking about DC motors and robots


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.


Showing the MIP (Mobile Inverted Pendulum) robot

Showing the MIP (Mobile Inverted Pendulum) robot

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.


The students had good questions and were attentive

The students had good questions and were attentive

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

Building a Reed Switch Brushless DC (BLDC) Motor

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 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:

1 kelvin reed contact dc motor contents

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.

2 reed switch motor pieces marked

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.


3 closeup of reed switch assembly

Close-up of the reed switch (note how the reed switch was soldered to the brass nails)

5 top view of reed switch motor

Top view of the completed motor (note how the reed switch is lined up with the magnet)


4 side view reed swith complete start testing

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.


6 reed switch motor complete and workingReed Switch Brushless DC motor working!

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

Infographics to the rescue!

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.



Via Sinotech

A new STEM program in eastern Kentucky

A few weeks ago we were asked to travel to eastern Kentucky and visit and a school that had recently started a STEM program. While there we learned most of the students were able to go to the University of Kentucky (UK)  to learn about the nine engineering disciplines that UK offered. Some students were ecstatic about what they learned from the professors and administrators. The second day some of the same UK representatives visited the school to discuss additional careers related to STEM. On the third day we had a session at the school about the various robots my sons and daughter have purchased or built (see below).



 Six robots, one brushed motor,  and one BLDC shown at eastern KY school 

The robots (L to R) shows the first robot we ever built at home – a wastebasket robot that was tethered to a manual control box. This used old TYCO motors installed with a circuit board inside the upside-down wastebasket. It ended up being one of the most popular robots that day.

The robot to the right of the wastebasket robot is called Sparki. It was programmed to avoid walls or other objects. Since it was slow, it did not garner a lot of attention. Someday the students will see how powerful the robot is. It uses an Arduino board as its brain and is very flexible to program.

Next up was a brushed motor; I used it to show the students that motors and/or servos form the basis of the infrastructure of a robot.

As can be seen above, next was an R2D2. This robot was bought pre-assembled and it was the hit of the day. It is completely autonomous and uses voice recognition to hear the command and normally follow through. On this day, R2D2 was quite obstinate – in a good way. We gave it some commands and even used the “Do you remember…?” (Chewbacca, CP3O, Darth Vader, etc.) question to get a response out of R2. Other interesting games we played was “Spin the Droid” and “Play Message.” The students were enthralled.

Next was a Lego Mindstorm NXT 2.0 basic robot. I had installed an app on my smartphone and was able to control it. With the third motor it could really peal out. One of the students wanted to write an app. Things are looking up.

Was able to take a laptop and the software to control the robotic arm. Originally the robot arm was tethered to a control box like the wastebasket robot and you had to control in manually, but a 3rd party company now sells a USB cable that ties to a laptop and you can use the computer to control the robot. This was a little advanced and the software was brand new so it was not as effective as I thought it would be.

The second motor was a brushless DC motor (BLDC) that uses a reed switch instead of a commutator and brush assembly. Explained the reed switch is pretty stable but not many of these are used in industry.

The last robot was a small robot from a company called Robotis. It is from a kit called OLLO and you can build approximately 12 different robots. You can also use their software to program them if you’d like. This robot was a line follower and it was speedy. The students liked how fast it ran around the black line.

Finally, if you look closely at the picture you will see a Rubik’s cube. As mentioned in a previous post I had a video of Mindcuber (another Lego Mindstorm NXT 2.0 robot) so the students could see how quickly it solve the Rubik’s cube shown. They all wanted one.


 Close up of most of the robots and motors

Overall, the students were really engaged. STEM is a new part of their curriculum and they are just getting started. After 1-1/2 hours and many questions, it was time to return to central Kentucky. It amazes me each time I do a STEM session to see how advanced these students are. Some really want to get down to the nitty gritty. I imagine if we had the time, we would have been there playing with the robots for another three hours or so.

Quote for the Day:  ”The people who get on in this world are the people who get up and look for the circumstances they want and if they can’t find them, make them.” — George Bernard Shaw



How many alternative fuel vehicles can you name?

A few weeks ago we featured electric cars as one industry that uses brushless DC (BLDC) motors. During investigation there was a blog I found that had a bunch of TLA (three-letter acronyms) for the alternative fuel vehicle industry. Below is a piece from the Schneider Electric blog that has defined these TLAs. That’s the beauty about blogs. There is always something to learn, but be careful, you can’t trust everything you read on the Internet.

Are you “trying to sort out all the different types of Alternative Fuel Vehicles now on the market? Here are some key terms and features of the industry and also a great resource that you can use to investigate further.

AFV – Alternative Fuel Vehicles. Alternative Fuel Vehicles (AFV) which run on ethanol, biodiesel, natural gas, propane, or hydrogen – all of which use less energy than gas.

FFV– Flex-Fuel Vehicles. Flex-Fuel Vehicles (FFV) are designed to run on gas or a blend of up to 85% ethanol.

EV – Electric Drive Vehicles. Electric Drive Vehicles-all use an electric motor to improve efficiency in some way, that motor can be powered by a battery, in combination with an internal combustion engine, or by a fuel cell.

  • HEV – Hybrid EV uses an electric motor and a combustion engine. These are designed to capture energy lost through braking (regenerative brakes) to power the electric motor.
  • PEV – Plug-In EV uses a highly efficient electric engine and electricity, powered by batteries that are charged by plugging into an outlet.
  • PHEV – Plug-in Hybrid EV use an electric motor and combustion engine and uses energy from a battery that is charged by plugging into an outlet or the electrical grid in some way. When electricity runs out the car continues using a gas engine or a generator (like an EREV).
  • EREV – Extended Range EVs when the battery runs out the combustion engine acts as a generator to power the battery and extend the range.
  • BEV – uses batteries to power the electric motor, fully runs on the plug in charge.
  • FCEV – Fuel Cell EV combines hydrogen fuel and oxygen to power the electric motor, the only exhaust is water – fully runs on the plug-in charge.

Learn more at the website

People have varying opinions on these alternative fuel vehicles. Some are adamant about using corn (that is used to make ethanol) to power vehicles when the corn can be used to feed people. Others feel the U.S. government subsidizes these vehicles and they should live on their own merits. Others say we should stop using fossil fuels altogether and go to these alternative fuel vehicles.

This post was written to help people become aware of he extent of alternative fuel vehicles in existence today. Some are in the testing stages and some are in production. Generally, these vehicles cost more than the gas powered vehicles so those that purchase them have a passion for the “green” environment. Some have enough cash to purchase these vehicles in order to save time by not purchasing gas. Right now there is an infrastructure problem. Slowly but surely towns, cities, and states are coming up with places to recharge your hybrid while on the road.

As you learn more about alternative fuel vehicles when you take STEM subjects, you will be able to make your own choice. We live in a land that provides you the opportunity to make choices and that is good. However, for each choice you make, you also incur responsibility. Be sure you choose wisely.


Quote for the Day:   ”Character, not circumstances, makes the man.” — Booker T. Washington


How about a new way to design and make DC motors?

Recently, we added a new topic to the website called brushless DC motors also known as BLDC. BLDC motors are used in many applications for several reasons: they are light, have high efficiency, and are quite compact.

One of the neat things you can do is to make different circuits that will turn the electromagnet on and off. This makes for some real innovative designs. Although we have built four BLDC motors from kits from the folks at the Simple Electric Motor company, they also have other kits that you can investigate and build. Once you feel comfortable about building these kits it is time to advance and come up with your own designs.

Here is the link to our new BLDC motor page. Enjoy something new!


Quote for the Day:  “It may be that those who do most, dream most.” — Stephen Leavock

What major industries use brushless DC motors?

In our last post we mentioned there are certain applications that use brushless DC (BLDC) motors. Succinctly, here are a few that you may or may not have thought about:

  • Do-it-yourself (DIY) home improvement projects industry,
  • Radio-controlled vehicles industry,
  • Heating, Ventilation, Air Conditioning (HVAC) industry, and
  • Electric car industry.

In DIY home improvement projects, people use power tools that have BLDC motors installed in the tool that makes them lighter and at times more powerful.

Radio-controlled (RC) vehicles such as airplanes, cars, helicopters, ships, and the latest craze, quadcopters, all use BLDC motors because of less maintenance, being compact, and being lighter.

The HVAC industry uses BLDC motors because they are lightweight, compact, have fewer maintenance needs, and are simple to replace.

Finally, there seems to be a need for alternative fuel vehicles these days. This has rejuvenated the electric car industry with new designs that have better reliability. Part of the increase in reliability has to do with BLDC motors. Below is an infographic from a U.S. company called Sinotech. I ran across this company when I was checking out BLDC motors. That is the beauty of the Internet – with Google, Bing, or Yahoo, all you have to do is come up with a search term and you can learn so much about motors, robots, and their place in the world.

Quote for the Day: “The grand essentials of happiness are something to do, something to love, and something to hope for.” — Chalmers


Via Sinotech

Introducing brushless DC motors

This week I’d like to introduce you to a new type of motor, called a brushless DC motor. Some people shorten brushless DC motor as BLDC motor. After building brushed DC motors for a few years, I yearned for a motor that would not be so hard to assemble the brushes and the commutator. This has been the number one problem when building a brushed DC motor. After searching the web, I found a website called Simple Electric Motors run by Mr. Serge Pozmantir. The website was devoted to Serge’s son, Stan, who won several Texas science awards with his motors and experiments. By now Stan has graduated and probably has a job somewhere.

Anyway, my sons were interested in learning how to build the BLDC motors so I bought a few. Below are two of the many kits you can purchase and build. Recently, Mr. Pozmantir has updated his website and it is much faster with better navigation than what he used to have.

BLDC Motor using optical control

BLDC Motor using optical control


The brushless motor above uses an opto interrupter circuit to make it work. Please note there are NO brushes to deal with. However, you must do some soldering and you have to be careful when you assemble these motors due to a sharp pins being used as part of the shaft. At the bottom of the picture you will see a small rubber grommet that covers the end of the sharp pin. The opto interrupter circuit is shown at the top of the picture. As the motor turns the circuit controls when to allow electricity to energize the electromagnet. This is a pretty fast motor, but not as fast as the one below.


BLDC Motor with Reed switch

BLDC Motor with Reed switch & transistor

This brushless motor uses a reed switch with a transistor to make it work. It is one of the simplest motors to assemble, is fast,  and it works very well at low voltages. The reed switch is shown on the left side of the picture between the motor shaft (with the “S” and “N” permanent magnets) and the upright support. If you look close you can see the reed switch is attached to the support. When the magnet on the shaft gets close to the reed switch, the two pieces of metal inside the glass tube become magnetized and are drawn to each other. At this point current flows through the transistor, the transistor opens, which then permits more current to flow to the electromagnet. As the magnet moves away, the reed switch moves back to its original position and no more current flows through the transistor and none through the electromagnet. Inertia keeps the motor running along with the reed switch and transistor circuit until the next magnet magnetizes the reed switch.

There is another kit that Mr. Pozmantir sells that uses a reed switch with a separate magnet that helps control the speed of the motor. If you want to learn more, hit the link above and check out the kits and experiments. They are put together well and you will enjoy building them.

Sometime in the future I will make videos of some of these BLDC motors and post them on the website, but in the meantime, enjoy these pictures.

Next week we will learn where these special BLDC motors are used.


Quote for the Day: “Make the little decisions with your head and the big ones with your heart. Do that, and you’ll be just fine.”   Kevin Roberts, CEO Saatchi & Saatchi, the largest advertising agency in the world