The must-have toy of the moment last winter was the “Hoverboard”. We all probably secretly wished them to be the boards from the Back to the Future series of films made real, but the more achievable reality is a self-balancing scooter somewhat akin to a miniature Segway. It seemed every child wanted one, schools banned them, and there was a media frenzy over some of the cheaper models that lacked protection circuitry for their li-ion batteries and thus had a tendency for self-incineration.
[Drew Dibble] is interested in the Power Racing Series (PRS), in which toy electric cars are souped up for competition. Casting around for a source of cheap and relatively powerful motors he lit upon the self-balancing scooters, and waited on Craigslist for the inevitable cast-offs. His resulting purchase had two 350W brushless hub motors and all the associated circuit boards for motor control, gyroscope, and oddly a Bluetooth speaker. The motor control board received an unknown two-wire digital feed from the scooter’s control board, so he set to work investigating its protocol. His write-up of how he did it is an interesting primer in logic line detective work.
Hooking up his logic analyzer he was quickly able to rule out the possibility of the control signal being PWM because all signals followed the same timing. Both lines had data so he was able to rule out I2C, for in that case one line would carry a clock. He was therefore left with a serial line, and taking the 38 microsecond timing interval, he was able to calculate that it had a rather unusual bitrate of 26315 BPS. Each packet had a multiple of 9 bits so he either had 9-bit or 8-bit with parity, and trying all possible parity schemes resulted in parity errors. Therefore the boards used a highly unusual 9-bit non-standard bitrate serial port. Some experimentation led him to an Arduino library, and he was able to get some movement from his motors. Some clever timing detective work later and he could make them move at will, success!
All his code for the project is on GitHub, for his 9-bit SoftwareSerial library and a motor control sketch.
If you want a real Back to the Future hoverboard then you may have to wait a while longer. We have featured a replica made as an unrideable floating artwork though, and a working board that is more of a personal hovercraft.
Continue reading “Reverse Engineering Hoverboard Motor Drive”
[XenonJohn] wrote in to let us know about updates and a recent test drive of an Electric Self-Balancing One-wheeled Motorcycle, fresh from the beach where he says it proved to be great fun to ride. The design and build have been updated since we last saw it as a semifinalist entry in the 2014 Hackaday Prize. The original, he says, “looked cool but was slow, cumbersome and really dangerous to ride.”
Since then it has been completely redesigned and now has a super fat kite-surfer wheel, a front crash skid with damper, and a variable geometry which allows it to steer properly despite just having one wheel. It does this by allowing the rider to shift their position relative to the wheel, instead of the seat always being rigidly locked directly above the axle.
That steering is a pretty clever upgrade, but we do wonder if the new crash skid will have an atlatl effect and really launch the rider in a crash. Our gut feeling aside, it is designed not to plant itself in the pavement, but to slide along (without ejecting the rider) until the vehicle loses all momentum.
There is something about self-balancing unicycles that attracts experimenters, each of whom takes a different approach. We see everything from this device constructed mainly from a Razor Scooter to this more polished-looking unit based on an earlier Segway clone design. [XenonJohn] reminds us that “there is still much to learn in this area and you can genuinely innovate even as a hobbyist. Also, you can only do so much on a computer, you then have to actually build something and see how well it works. [This recent test] shows what you can do if you just keep on experimenting.” Video of the test drive is below.
Continue reading “Self-Balancing One-Wheel Motorcycle Tears Up the Beach”
Throughout time it’s just been plain cool to genie around from point A to B on some form of personal portable hardware. Understandably so, it was the goal of [Dane Kouttron] to modify and improve the common standard in such a way that anyone could hop on his board and ride without a period of flailing to keep balance. In his Flying Nimbus project, the rider floats aloft a single power-driven wheel that will even do the balancing bit for you.
Inspired by some interesting aluminum scraps and an old 3 phase DC servo driver, [Dane] starting conjuring ideas of combining the two in order to produce his own self balancing form of transportation. A chunky reused tire from a local go-kart track turned out to serve as his wheel of choice which would mount between the feet of the rider. After ordering a 48v hub motor and waiting for it to make its way over from China, [Dane] took the time to model all of the individual parts, motor, and wheel in CAD to figure out the needed measurements for the custom pieces he’d later fabricate to fit around them. The aluminum frame that the rider stands upon not only houses and conceals the power cells and electronics running the central wheel, it also illuminates white light from the sides to stand out at night. Along the road of troubleshooting, [Dane] eventually scored a complementary top-notch servo drive from AMC, who ultimately wanted to see his project rolling as badly as he did. There is a load of detailed documentation on the layers of problem solving that went into the project on his blog, as well as more on the hardware used by [Dane] to get the board actively balancing. Seeing the final product should further enforce that there is no better way to get around then on the likes of something you made yourself:
Continue reading “Surfing Around on a Self-Balancing Cloud”
Hanging out at one side of the Atmel booth at Maker Faire was [Pamungkas Sumasta] who was showing off his Arduino cellphone called Phoenard. We really like the form-factor but its hackability is where it really shines. [Sumasta] showed off the menu system which is quite snappy and makes it simple for you to add your own applications. Software isn’t the only thing you can customize, as there’s a connector at the bottom of the phone. He showed off a breadboard attachment which was hosting LEDs of various colors. Their intensity can be altered using a simple slider app on the touchscreen. But there’s more power if want it. Also on exhibit was a self-balancing robot body which has a connector at the top for the phone.
[Sumasta] won the Atmel Hero contest and we assume that’s how he made it all the way to San Francisco from The Netherlands for Maker Faire. You can learn a few more technical details about Phoenard on the Facebook page.
No one has time to hone their balancing skills these days, and if building your own Segway doesn’t generate enough head-turning for you, then the self-balancing unicycle from the guys at [Scitech] should. Their build is chain-driven, using easy-to-find salvaged Razor scooter parts. Throw in a motor controller, 5DOF IMU and some batteries and it’s almost ready to burn up the sidewalks in hipster-tech style.
Some of the previous unicycle builds we’ve seen are a little on the bulky side, but the [Scitech] cycle aims for simplicity with its square tube steel framing and footrests. As always, unicycle builds like these take some effort on behalf of the rider: shifting your weight controls steering and throttle. The [Scitech] gang also discovered that it’s usually best when you don’t accidentally wire the motors up to the controller backwards. We recommend that you find a helmet and watch the video after the break.
Too-cool-for-unicycle hackers can build a dangerously fast e-skateboard instead.
Continue reading “Yet Another Self-Balancing Unicycle”
The 2013 IEEE International Conference of Robotics and Automation was held early in May. Here’s a video montage of several robots shown off at the event. Looks like it would have been a blast to attend, but at least you can draw some inspiration from such a wide range of examples.
We grabbed a half-dozen screenshots that caught our eye. Moving from the top left in clockwise fashion we have a segmented worm bot that uses rollers for locomotion. There’s an interesting game of catch going on in the lobby with this sphere-footed self balancer. Who would have thought about using wire beaters as wheels? Probably the team that developed the tripod in the upper right. Just below there’s one of the many flying entries, a robot with what looks like a pair of propellers at its center. The rover in the middle is showing off the 3D topography map it creates to find its way. And finally, someone set up a pool of water for this snake to swim around in.
Continue reading “Best robot demos from ICRA 2013”
The VertiBOT is a self balancing robot project taken on for the purpose of exploring how the sensors work in conjunction with some PID algorithms.
[Miguel] didn’t roll any extras into the build. But you have to admit that makes it look interesting. There’s almost nothing to it and yet, as you can see in the clip after the break, he accomplished everything he set out to.
The body and wheels are 3D printed, with black bands for tires to help give it some traction. Note the connection in the center of the body which allowed him to make a longer part by printing in two stages. On the electronic side of things he’s using an Arduino Nano. A level converter lets it communicate with the 6 DOF IMU board which is used to detect movement. Three potentiometers provide a way for him to tweak the PID loop without having to bother with reflashing any code. And of course there’s an option to control it remotely thanks to a Bluetooth module also in the mix.
Continue reading “Clean and minimal self-balancing robot”