[Greg06] started learning electronics the same way most of us did: buy a few kits, read a few tutorials, and try your hardest to put a few things together. Sound familiar? After a while, you noticed your skills started increasing, and your comfort level with different projects improved as well. Eventually, you try your hand at making your own custom projects and publishing your own tutorials.
[Greg06’s] robot has a quadruped based, housed within a 3D printed spherical body. The legs are retractable and are actuated by tiny servo motors inside the body. [Greg06] even included an ultrasonic distance sensor for the obstacle avoidance mechanism. Honestly, if it weren’t for the ultrasonic distance sensor protruding from the spherical body, you might think that the entire robot was just a little Wiffle ball. This reminds us of another design we’ve seen before.
If that weren’t enough, the spherical head can rotate, widening the range of the ultrasonic distance sensor and obstacle avoidance mechanism. This is accomplished by attaching another servo motor to the head.
Most of us have been there, some projects just don’t get finished. Everyone shelves an in-progress build from time to time, and some hackers drop almost every project for fully finishing it. Why does it happen? What can we do about it? Or does it even matter? My own most memorable one is the wine glass rack I was making for my sister’s birthday, still sitting incomplete on a shelf eleven years later.
The answer may lie in what you consider to be a “done” project. Is it a fully completed build with every possible feature implemented and polished? With that rubric you could be counting all of your completed projects on one hand. What are you really getting out of your personal projects? It’s an interesting topic to consider as pivoting your mindset can end up boosting your productivity. So let’s dig in!
By now we’ve come to expect a bountiful harvest of licensed merchandise to follow every Star Wars film. This year’s crop included many flavors of BB-8 so every fan can find something to suit their taste. At the top of this food chain is a mobile interactive “Hero Droid BB-8”. For those who want to see how it works, [TheMikeSenna] cracked open his unit to feed our curiosity.
Also called “Spin Master BB-8” for the manufacturer, this toy is impressively sophisticated for its price point. The video surveyed the mechanical components inside the ball. Showing how the droid travels, and how the head articulates.
Most of us have seen employees of Boston Dynamics kicking their robots, and many of us instinctively react with horror. More recently I’ve watched my own robots being petted, applauded for their achievements, and yes, even kicked.
Why do people react the way they do when mechanical creations are treated as if they were people, pets, or worse? There are some very interesting things to learn about ourselves when considering the treatment of robots as subhuman. But it’s equally interesting to consider the ramifications of treating them as human.
The Boston Dynamics Syndrome
Atlas being pushed
Spot being kicked
Shown here are two snapshots of Boston Dynamics robots taken from their videos about Spot and Atlas. Why do scenes like this create the empathic reactions they do? Two possible reasons come to mind. One is that the we anthropomorphize the human-shaped one, meaning we think of it as human. That’s easy to do since not only is it human-shaped but the video shows it carrying a box using human-like movements. The second snapshot perhaps evokes the strongest reactions in anyone who owns a dog, though its similarity to any four-legged animal will usually do.
Is it wrong for Boston Dynamics, or anyone else, to treat robots in this way? Being an electronic and mechanical wizard, you might have an emotional reaction and then catch yourself with the reminder that these machines aren’t conscious and don’t feel emotional pain. But it may be wrong for one very good reason.
Imagine trying to make a ball-shaped robot that rolls in any direction but with a head that stays on. When I saw the BB-8 droid doing just that in the first Star Wars: The Force Awakens trailer, it was an interesting engineering challenge that I couldn’t resist. All the details for how I made it would fill a book, so here are the highlights: the problems I ran into, how I solved them and what I learned.
I have a good background working with high voltage, which for me means over 10,000 volts, but I have many gaps when it comes to the lower voltage realm in which RC control boards and H-bridges live. When working on my first real robot, a BB-8 droid, I stumbled when designing a board to convert varying polarities from an RC receiver board into positive voltages only for an Arduino.
Today’s question is, how do you convert a negative voltage into a positive one?
In the end I came up with something that works, but I’m sure there’s a more elegant solution, and perhaps an obvious one to those more skilled in this low voltage realm. What follows is my journey to come up with this board. What I have works, but it still nibbles at my brain and I’d love to see the Hackaday community’s skill and experience applied to this simple yet perplexing design challenge.
I have an RC receiver that I’ve taken from a toy truck. When it was in the truck, it controlled two DC motors: one for driving backwards and forwards, and the other for steering left and right. That means the motors are told to rotate either clockwise or counterclockwise as needed. To make a DC motor rotate in one direction you connect the two wires one way, and to make it rotate in the other direction you reverse the two wires, or you reverse the polarity. None of the output wires are common inside the RC receiver, something I discovered the hard way as you’ll see below.
Three things that I love about participating in Maker Faires are seeing all the awesome stuff people have done over the past year, spending time with all my maker friends in one big room over two days and the reactions to what I made. The 2016 Ottawa Maker Faire had all this in spades.
There’s just something about BB-8 that touches people. I once heard of a study that showed that when buying kid’s toys, adults were attracted to circles, that that’s the reason teddy bears often have round heads with big round eyes. Similar reactions seem to happen with BB-8, the droid from last year’s Star Wars movie. Adults and kids alike pet him, talk baby-talk to him, and call to him with delight in their voice. I got those reactions all throughout the Maker Faire.
But my favorite reaction happened every time I removed the head and lifted the top hemisphere of the ball to expose the electronics inside. Without fail the reaction of adults was one of surprise. I don’t know if it was because of the complexity of the mechanism that was revealed or because it was just more than they expected. To those whom I thought would understand, I gave the same speech:
“This is the remote control receiver taken from a toy truck, which puts out negative and positive voltages for the different directions. That goes to this ugly hack of a board I came up with that converts it all to positive voltages for the Arduino. The Arduino then does pulse width modulation to these H-bridge driver boards, for speed control, which then talk to these two drill motors.”
Those I wasn’t sure would understand were given a simpler overview. Mine’s a hamster drive (we previously covered all the possible ways to drive a BB-8) and so I showed how it sits on two Rollerblade wheels inside the ball. I then flipped it over to show the heavy drill batteries underneath, and then explained how the magnets at the top of the drive mechanism attracted the magnets under the head, which got another look of revelation. All went away satisfied.
But BB-8 sometimes needs a break from human interaction and seeks out its own kind, like Bowie which you can read about below along with more awesome Maker Faire exhibits.