Building a Functional RC Car at 1:150 Scale
Diorama111 packs a full RC drivetrain, steering system, and working lights into an impossibly tiny 1:150-scale Toyota ProBox.
Miniaturizing everyday objects has a way of making even the most ordinary things seem really special. YouTuber Diorama111 has built a reputation around shrinking things down to incredible scales, including this 1:150-scale N-gauge train with a working LCD screen. Diorama111’s latest project takes on a tiny, Matchbox-style Toyota ProBox, which is converted into a fully functional RC car.
RC cars may be common, but building one at 1:150 scale presents an entirely different set of challenges. At this size, the entire vehicle measures only a few centimeters long, leaving virtually no room for traditional electronics, motors, or steering systems. For this reason, nearly every component inside the miniature ProBox had to be custom-designed, fabricated, or heavily modified to fit within the tiny plastic shell.
The build begins with an off-the-shelf Toyota ProBox model. After stripping the interior, the available space is packed with new hardware. A custom rear drivetrain uses a DC motor, reduction gears, and a brass-bushed axle to provide realistic acceleration and low-speed control. Small as it may be, the drivetrain delivers smooth movement that closely matches the scale speed of a real vehicle.
Instead of using a traditional RC servo for steering, Diorama111 created a miniature linear actuator driven by a second DC motor. The mechanism uses a threaded screw and sliding runner to move a custom tie rod connected to the front wheels. To achieve proportional steering, a tiny photoreflector sensor monitors the actuator position, providing closed-loop feedback similar to a full-sized servo system.
Power comes from a 25mAh lithium-polymer battery mounted directly above the custom control electronics. The vehicle is operated through an infrared communication system, and commands are transmitted from a homemade controller featuring dual analog joysticks, allowing independent throttle and steering control.
As if fitting a complete RC system inside the model were not impressive enough, Diorama111 also added fully functional lighting. Microscopic surface-mount LEDs were installed behind the headlight and taillight lenses using hair-thin magnet wire routed through the roof of the body shell. The headlights illuminate during forward driving, and the rear lights brighten when reversing.
The finished vehicle handles well and is capable of smooth turns, figure-eight patterns, and precise parking maneuvers. Watching the tiny ProBox cruise across a cutting mat with realistic lighting is definitely worthy of a double take.