Self Balancing Vehicle Inspired By Bicycles Of Yesteryear

Self balancing chopper

[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.


23 thoughts on “Self Balancing Vehicle Inspired By Bicycles Of Yesteryear

    1. 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

    1. 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.

    1. 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.

  1. 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.

  2. 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.

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