I talk to many engineering friends who say they took apart their toys (and everything else). I was not like that. I didn’t know it was possible to take objects apart. I definitely didn’t know how much I could learn. I never imagined how fun it would be.
As soon as I saw the Sphero BB-8 in a commercial I wanted to know how it worked. The small, smartphone-controlled robot has a magical, alive feeling. It should just be a ball with a magnetic head, Sphero has made the ball robots for a while. But pop a magnetic head on there and I was smitten.
I thought about how the device had to work:
- It communicates with the smartphone via common Bluetooth Low Energy (BLE).
- Motors move it around.
- It charges by sitting in a cradle so it must be inductive charging.
- Playing with the BB-8 application on my smartphone (see Figure 1-1), I could see other pieces that had to be part of the system:
- It must have accelerometers and gyroscopes (probably MEMS inertial sensors, I’ve worked on these and find them amazing so there will be a lot more about inertial sensors later).
- It says it can detect lifeforms. That would likely be from an infrared detector. However, it says “lifeform detected” whether it runs into me or the chair so BB-8 may be faking life form detection.
- It has lights inside it. It has many different colors depending on whether it is charging, connecting to the phone, or crashing into the wall.
- Another light helps orient BB-8 to me. This is called the “taillight” and is always blue, in a different location than the other lights.
For most devices, this would have been enough for me. I can draw a block diagram and thanks to years of experience building things, figure out the electronic and mechanical components in a device, block out the software and use all that to determine how much the device will probably cost to produce. Frankly, that isn’t all that much fun and I wanted to try another, more hands-on path.
Grabbing my handy screwdriver, I was ready to take BB-8 apart and really explore the insides. Unfortunately, it doesn’t have any screws. To open BB-8 required courage, commitment, and a Dremel tool with a cutting bit (see Figure 1-2).
Once the outer shell was cracked open (Figure 1-3), I could see how it rolled around inside the smooth case.
Lifting the robot out of the shell (see Figure 1-4). I could see how the head was held on with a magnet. I could see the charging method and the batteries. I could see how there were only two motors leading to more questions like: How can it turn? How can it nod or shake its head and not move the body?
I thought I had questions before I opened it. I figured I’d get some answers after I opened it. That was only partially true: after I’d spend an hour or two looking at the insides, I had a lot more questions.
I started to identify the components. I looked at the ID printed on the chips and looked them up online. Some parts were more difficult to identify than others. I traced through subsystems and looked at signals as BB-8 tried to move without its cover. It was awesome and fun and educational and exactly what I want to share with you here.
Another Toy: Quadcopter
Deep in the joy of discovering with BB-8, I realized that I could burble about engineering concepts for whole tens of minutes at a time and, for a change, people would listen because BB-8 was the star. I could explain PWMs and inertial sensors and other assorted jargon as much as I wanted and the audience would hang around hoping to play with the bot! Bwahahahahaha!
Clearly drunk on power, I looked around for another toy I could take apart. Of course, it should have the same “how does that even work” spark that BB-8 has. Have you seen the tiny quadcopters? The ones which are a little bigger than a quarter? They cost as little as $10 when I found them on sale. It seemed like something I should try out.
As I am a terrible, awful remote control pilot, it didn’t take long for me to have a couple quads that couldn’t fly very well anymore. I didn’t feel the least bit of sympathy for the device as I took both the controller and the tiny quadcopter apart (see Figure 1-5).
Filled with a neat little microcontroller, a wireless communication chip, and an inertial sensor (!), the quadcopter packs as much education as BB-8 in a tinier package. Even the simple-looking quadcopter controller had many cool features (and was a little bigger and easier to pull signals from).
While it’s fun to tear apart the outer covering to see what’s inside, being more structured about the teardown makes it easier to put the device back together again. I often take a bunch of pictures as I go along. This is an easy way to determine how this part fits into that one when I try to reassemble it. While the photos provide a way to document the interesting mechanical features, I also sketch a block diagram as I go along, one that focuses more on the electrical subsystems.
The sketch tends to start with a microcontroller (I’m an embedded software engineer, just about everything starts with a microcontroller since that provides the brains of the system). That is the first chip I try to identify. I look at all the chips that have more than three pins and try to figure out what they are, usually by searching around online. I typically only manage to find 75% of them so there are always a few guesses. Then I look at the buttons and other user interface features to figure out how they are connected. Lights, motors, and audio come next. They all have subsystems that can be tricky to figure out but once you’ve seen a few, they begin to look alike.
Essentially, my goal is to break the system into smaller and smaller parts until I understand how it works. I get a rush of happiness when I finally get it.
Figure 1-6 shows my partial understanding of the quadcopter. I’ve drawn and redrawn the sketch as I get new information. As I write about the quadcopter, I’ll fill in more of the blanks until it is as done as I can make it.
One More Toy: Karaoke
By this point, I knew I wanted to write a book about taking apart toys. I had learned so much and wanted to share it. I also knew that writing a book would keep me digging deeply into each of these toys, not wandering off to play with the next shiny piece of technology.
To round out my collection, I really wanted a pink toy. Oh, not a pink quadcopter (yes, they come in lots of colors). I wanted a Pink Aisle toy, something from the girls section of the toy store. This proved more difficult than I anticipated. There isn’t a lot of interesting technology in the Pink Aisle, especially when I set down my goals of under $50 and not produced by Leapfrog (I worked there so it seemed like cheating to take apart one of their toys). A friend suggested a karaoke unit (see Figure 1-7).
While it went over my budget and wasn’t exactly what I had in mind, the karaoke has been far more amazing on the inside than on the outside (see Figure 1-8).
It is made to be very cheap to manufacture with modular parts to allow a wide range of different toys with similar electronics. I found it easier to understand the small, very common subsystems of the karaoke: buttons, lights, knobs, speakers, and so on. I knew how these interacted with the software I write, even how to order them and put them into products. However, until I started poking around inside the karaoke, I didn’t really know how they worked.
Take apart a Kleenex box. Seriously, this is a low-cost, getting started activity. You don’t need to do the Going Further tasks in other chapters. I hope you enjoy the material without getting your hands dirty. But this once, really, please, try it.
Take apart a Kleenex box. Oh, you can wait until it is almost empty if you must but you don’t have to, it will go back together (probably, with a little tape).
Start by gently loosening the glued together edges of the cardboard box. If you have a side opening one, you can open one edge and look inside.
See how the tissues fold into each other so that pulling one out leads half-pulls the next one? Now, take the tissues out (carefully if you want to use them). Finish opening the cardboard box until you can lay it out flat.
Take a look at the cardboard. Why is it shaped like that? Is that how all boxes are shaped? Why this box shape?
Are there additional things printed on parts of the cardboard that you wouldn’t see from the outside? Usually there are color swatches so someone (some robot?) can see if the printer is running low on ink. There might be a serial number or a bar code to indicate what factory or machine made the box.
Who did that? Who made it? Who designed the box to have hidden features? Who was the creator? Why did they make it this way? Was there another way?
Someone made this. Someone thought about it. There is a person who made a Kleenex box. And then there are all the people who made it better.
Behind the Kleenex box is an engineer (or team of engineers). They thought about the box and the user. They considered how to best manufacture the box and fill it with Kleenex. Every step of the path, there were tradeoffs that had to be considered. Cost is always a factor but I wouldn’t have thought to put serial numbers and printer color checks on something as mundane as a Kleenex box. I would have been wrong.
By thinking about how the Kleenex box is made, you put yourself in their shoes for a moment and look at the world from a different perspective. If you’ve never done this before you might have learned something, something that you can then show someone else. If you have done it, there are always new methods and technologies to appreciate.
And that’s what this book is about; whether you are here to see the guts of toys for the first time or the hundredth, I hope you have fun, learn something, and pass the enthusiasm for engineering along to others.
This is a series. If you’d like to read them in order, check out the Taking Apart Toys index.