[XenonJohn] is not a newcomer to the world of self balancing vehicles. He was part of the Medicycle team and a semifinalist for The Hackaday Prize. Working on the Medicycle had exposed some opportunities for improvement of the design, the most significant being the single wide wheel supporting the vehicle and rider. The unicycle design was more difficult to learn to ride than that of a two-wheeled nature. [XenonJohn] wanted to make an improved self balancer and this new one will have two wheels that are independently controlled.
Although the finished product looks like it started with a bike frame, the self-balancer’s frame is actually completely custom. The handlebars and banana seat were purchased new as aftermarket parts for old-style bicycles. Powering the two wheels is a pair of 24v brushed motors, conveniently each one came with a 6:1 reduction gearbox pre-installed. The wheels are a complete compilation of parts not intended to go together. The BMX bike rims were laced to mountain bike front hubs. The hubs have provisions for a disk brake but [XenonJohn] mounted a large toothed pulley there instead. A belt then connects the drive motor gearboxes to the pulleys completing the drive train.
The LiFePO4 battery kit was purchased off eBay and puts out 24v and 15AH using eight cells. These batteries alone were a hefty percentage of the projects cost, costing nearly $300. Controlling the vehicle is an Arduino Mega that makes use of the FreeSix IMU library. The Mega receives inputs via I2C from a Sparkfun SEN-10121 board that contains both accelerometers and gyroscopes along with turn switches connected to the ‘brake’ levers on the handlebars. The Arduino then sends commands to the 25 amp Sabertooth motor controllers to keep you balanced as you buzz around town.
Video below.
This is just awesome!
If it could go faster it would be great to race them.
I saw “TG T3 Electric Self-Balancing Bike Motor Unicycle Monocycle Mini Solo Scooter ” for $450 on DX a while back.
That’s going to be an interesting product for a tear down. :)
Well no actually, The TG T3 etc…… is just another of those Chinese ones you stand on, copied from the SoloWheel.
The best proper electric unicycle with seat, steering mechanism and handlebars I have seen so far anywhere in the world is actually this Russian one which does not come up at all in most search engines: http://www.youtube.com/watch?v=q3S1YWMmXbQ
About US$1000 but that was a few days ago so may be even cheaper now with the economic changes going on right now.
That’s what I was thinking would be good for the prize entry one. Two wheels would be more stable and better for turning. I still think they’d be better further apart.
Didn’t want to just build a Segway with a seat on top, but still wanted stability of 2 wheels, but with legs on outside of the wheels.
Why have the spoke cover disks on the inside? The outside is where a rider is likely to get hands or feet into the works. The tires need more air too.
Sorta looked to me like there was something in/on the cover at regular intervals. So maybe for some sort of opto sensor or hall effect sensor. I dunno, that’s a best guess at best :P
It just looks nice that way since was trying to make it a little like a bike so did not want the full “solid” wheel effect.
Only there for decoration, not essential to make the machine work.
is it just me or does he look scared shitless to drive this more than 5 mph ?
Yes true. It can be scary. I work in a hospital too.
If it goes wrong your face ends up in the ground. 10 or 12mph does not sound like very fast but it is very fast to fall over onto your face! It will go a lot faster in theory, I just have not explored that yet. My driveway is not level either so until software truly dialled in there is always the risk of uncontrolled freewheeling off down the hill. Much easier to ride than the MediCycle was though, which was a seriously dangerous beast.
make a swing out front wheel, so when you need to stop you can… DUH
Wow .. awesome. We are trying to build something similar – an open source personal transportation device here in India. We are basing that on a single wheel unicycle model – It looks like only that design is compatible on Indian roads :) Find more details here – http://www.fireflyunicycle.com
p.s. – We are just starting to build it.
Your link does not work
May I ask a stupid question? Why the brake levers (probably used for control) are turned backwards?
The left handlebar has a twistgrip to control speed, the right has a “deadman” kill switch which has to be pressed at all times. This leaves just your thumbs (underneath) free to pull up on the levers. The levers are just switches to steer left or right with so you do not have to pull hard on them.
Great work!
Go Faster! Don’t be Skeerd!
I don’t think I could ever bring my self to sit on a banana seat, or be seen anywhere near one for that matter, but to each his own… but on the ladies model, sure. But lets not start #bananaseatgate here or something.
And as for the controls being “backwards”, probably less likely to squeeze one by accident due to sudden motion. I’ve seen things like self propelled rotor-tillers that have them mounted the usual way and it can create a “positive feedback” situation, where the thing wants to take off, and in doing so, makes you press “go” even harder…
And the site still looks like dogshit and hurts my eyes.
The sissy bar is waaaay to small. For true ’70s badassery, the sissy bar must extend above the riders head, and be crowned with a 3d printed H.A.D. logo.
Add a real sissy bar and I will be a true believer.
If machine fails frame tips forwards and sissy bar smacks you in the back of the head. I may fit one that kind of clips on so it comes off in a crash! That might work.
Who is the band? Awesome music..
A free AC/DC clone band who allow their music to be attached to YouTube vids for free.
This bikes model looks more balanced and this will be a good bikes for children