12v or 6v ride on vehicle control bar

Description:
This is a simple 3D printable modification designed to replace the factory knobs on common 6V and 12V ride-on vehicles, like those widely available on Amazon and other retailers.

I work with children who have complex neurological and motor needs. These bars enable low-tech access modifications to make ride-on toys more usable. Most of these vehicles are designed like zero-turn lawn mowers, requiring bilateral, coordinated hand use to drive. That’s often not possible for children who are developmentally delayed or still learning to control movement primarily at their midline.

This modification links both joystick levers with a single bar. Pulling or pushing the bar activates both controls simultaneously, making it easier to operate. In my experience, reversing the direction (so pulling moves the vehicle forward) feels more intuitive for many kids. I speculate this is because children who haven't crawled or walked often associate pulling with bringing something toward themselves—so pulling the bar “brings the world closer.”

If your child responds better to different directional behavior, you can reverse the lever polarity by either:

Rotating the switches 180° after removing them, or

Swapping the terminal leads on the underside.

Installation:

Remove existing knobs.

Push-fit the bar onto the control stems.

Optionally drill out the original knob threads and use a heat-set insert with an M3x30 socket head bolt for a more secure fit.

Spacing can vary slightly between models, so reach out if you need a tweak or custom fitting.

In the photos:

The backrest is made from HDPE board, mounted with elevator bolts, washers, and nyloc nuts.

The harness shown is a generic car seat-style product. I’m not endorsing any particular brand—it’s included here only for reference.

Link to common base model:
Kidzone Bluetooth Ride-On Vehicle