The Propeller Clock — Lucas Marques

The Problem

The objective was to create a digital clock that appeared to float in mid-air using a mechanical optical illusion. The technical hurdles involved synchronizing a spinning display to the human eye's persistence of vision and transferring power to a board rotating at 600 RPM without tangling wires.

Propeller Clock displaying six digits in mid-air — The completed Propeller Clock displaying a stable 6-digit time interface in mid-air.

The Engineering

I designed a system using a linear array of 7 LEDs controlled by an Intel 8051 microcontroller. Power is transferred via carbon brushes to the spinning control board. An infrared photodiode detects a fixed beam on the base to trigger an interrupt every revolution (100ms), synchronizing the LED flashes to create a stable 6-digit display over a 360-degree arc.

Intel 8051 microcontroller control board — Control board housing power management systems.

Propeller clock logic and power regulation schematic — Circuit diagram with the logic and power regulation design.

Linear array of seven light emitting diodes — Linear 7-LED array.

High-speed direct current motor base assembly — DC motor (bottom view).

Carbon brush power transmission mechanism — Carbon Brush Contact.

Infrared optical synchronization photodiode sensor — Infrared optical sensor.

The Results

The project resulted in a fully functional prototype that successfully generated the "floating screen" illusion. It served as my capstone project, securing my technical degree in electronics and validating my skills in embedded systems and mechanical design.

The Propeller Clock demonstration video.