Hoverboards: How Do They Work?

The Hoverboard Controversy

Hoverboards, or more accurately, balance boards, self-balancing scooters, or Segways without handlebars, were one of the hottest items last holiday season. In more recent news, they've become infamous for exploding lithium ion batteries and unstable control. So what's the deal with these machines being labeled as "unsafe for human use?" Are they unsafe products? Do they get a bad reputation because of negligent parents buying toys for their children that have as much stored potential energy as a stick of dynamite? As with most controversies, we discovered the situation to be some of both. So what do you need to know if you're interested in a hoverboard?

How Does a Hoverboard Work?

Self-balancing boards have frames that pivot in the center. The electric motors and sensors that detect speed and tilt angle are actually inside of each wheel. The gyroscopes receive the data from the tilt sensors in the wheels and relay it to the logic board, keeping the board upright at all times. There are switches under each foot pad that trigger an infrared LED light, which triggers a sensor. The light remains on when the rider keeps their feet flat, letting the logic board know not to run the motors. When the rider leans forward, the switch turns off the LED light, then the sensor lets the logic board know to spin those wheels. Since the motors are independent of one another, a rider can actually do circles in place. One of the better explanations of how they work can actually be found on a website called BestElectronicHoverboard.com, not the website we were expecting, but a surprisingly informative page.

The inner workings of an AlienBoard BatWings

In most hoverboards, the lithium ion batteries and the logic board are on opposite sides to reduce heat. There have been instances of boards bursting into flames while being ridden; these are likely due to poor battery position and insulation. Some teardowns have shown the insides of inferior hoverboards to have a mess of wires and nothing to hold the battery in place. There are safety standards for the individual components in hoverboards, but none for the boards themselves. Below is a teardown of a popular hoverboard model.

Test Drive!

The folks at AlienWheels were kind enough to send us an AlienBoard BatWings for testing and we were pleasantly surprised with its performance. It's more expensive than most of the hoverboards on the market, but it has CE, FCC, and RoHS certificates. One reason that the BatWings is so popular is the Samsung lithium battery. A lot of the low-quality hoverboards that are bursting into flames have poorly made, unregulated battery packs. We left the board charging overnight once and are pleased to say that our hoverboard did not explode (Please, do not attempt).

The Samsung battery cell 

We rode the BatWings pretty hard for extended periods of time and didn't experience any overheating. The BatWings also has Bluetooth speakers with surprisingly good sound quality. It may not be the most practical accessory, but we did thoroughly enjoy making the other businesses in our office complex jealous as we hovered around the building bumping Biggie Smalls. You can see the specs on this version of the new product segment below:

Batwing specifications courtesy of Alienwheels

How Can Future Designs Improve? 

Because of their small wheels and non-existent suspension, hoverboards don't do well outdoors. Cracks in pavement, uneven sidewalks, and even pebbles can send you flying off your board if you're going fast. In order to accomplish this; hoverboards are either going to need bigger wheels and tires, or some kind of suspension. Both of which are problematic due to the way these boards work. Bigger wheels and tires will require more power to produce the necessary torque in order to propel them.
These boards seem to already be pushed to their limits in the current form, and more powerful batteries could lead to more volatile contraptions. Adding suspension is a complex problem because the sensors need to have constant stability in order to keep the board balanced. The platforms where the rider's feet reside, need to have a stationary axis, otherwise bumping around will cause the footpads to accelerate and decelerate in a fairly unpleasant motion.

But most of these problems stem from the batteries in some way or another. For whatever reason many of similar products "require" only 90 minutes to change. If we go past that, well, good luck. These little headless Segways need to have an over-charge protection system, and it blows our mind that a device this expensive doesn't! So someone, please do us all a favor and quickly design a better board. It won't be hard.